Commit Graph

564 Commits

Author SHA1 Message Date
Linus Torvalds
73d7cf0710 ARM:
- Remove the last leftovers of the ill-fated FPSIMD host state
   mapping at EL2 stage-1
 
 - Fix unexpected advertisement to the guest of unimplemented S2 base
   granule sizes
 
 - Gracefully fail initialising pKVM if the interrupt controller isn't
   GICv3
 
 - Also gracefully fail initialising pKVM if the carveout allocation
   fails
 
 - Fix the computing of the minimum MMIO range required for the host on
   stage-2 fault
 
 - Fix the generation of the GICv3 Maintenance Interrupt in nested mode
 
 x86:
 
 - Reject SEV{-ES} intra-host migration if one or more vCPUs are actively
   being created, so as not to create a non-SEV{-ES} vCPU in an SEV{-ES} VM.
 
 - Use a pre-allocated, per-vCPU buffer for handling de-sparsification of
   vCPU masks in Hyper-V hypercalls; fixes a "stack frame too large" issue.
 
 - Allow out-of-range/invalid Xen event channel ports when configuring IRQ
   routing, to avoid dictating a specific ioctl() ordering to userspace.
 
 - Conditionally reschedule when setting memory attributes to avoid soft
   lockups when userspace converts huge swaths of memory to/from private.
 
 - Add back MWAIT as a required feature for the MONITOR/MWAIT selftest.
 
 - Add a missing field in struct sev_data_snp_launch_start that resulted in
   the guest-visible workarounds field being filled at the wrong offset.
 
 - Skip non-canonical address when processing Hyper-V PV TLB flushes to avoid
   VM-Fail on INVVPID.
 
 - Advertise supported TDX TDVMCALLs to userspace.
 
 - Pass SetupEventNotifyInterrupt arguments to userspace.
 
 - Fix TSC frequency underflow.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "Many patches, pretty much all of them small, that accumulated while I
  was on vacation.

  ARM:

   - Remove the last leftovers of the ill-fated FPSIMD host state
     mapping at EL2 stage-1

   - Fix unexpected advertisement to the guest of unimplemented S2 base
     granule sizes

   - Gracefully fail initialising pKVM if the interrupt controller isn't
     GICv3

   - Also gracefully fail initialising pKVM if the carveout allocation
     fails

   - Fix the computing of the minimum MMIO range required for the host
     on stage-2 fault

   - Fix the generation of the GICv3 Maintenance Interrupt in nested
     mode

  x86:

   - Reject SEV{-ES} intra-host migration if one or more vCPUs are
     actively being created, so as not to create a non-SEV{-ES} vCPU in
     an SEV{-ES} VM

   - Use a pre-allocated, per-vCPU buffer for handling de-sparsification
     of vCPU masks in Hyper-V hypercalls; fixes a "stack frame too
     large" issue

   - Allow out-of-range/invalid Xen event channel ports when configuring
     IRQ routing, to avoid dictating a specific ioctl() ordering to
     userspace

   - Conditionally reschedule when setting memory attributes to avoid
     soft lockups when userspace converts huge swaths of memory to/from
     private

   - Add back MWAIT as a required feature for the MONITOR/MWAIT selftest

   - Add a missing field in struct sev_data_snp_launch_start that
     resulted in the guest-visible workarounds field being filled at the
     wrong offset

   - Skip non-canonical address when processing Hyper-V PV TLB flushes
     to avoid VM-Fail on INVVPID

   - Advertise supported TDX TDVMCALLs to userspace

   - Pass SetupEventNotifyInterrupt arguments to userspace

   - Fix TSC frequency underflow"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: avoid underflow when scaling TSC frequency
  KVM: arm64: Remove kvm_arch_vcpu_run_map_fp()
  KVM: arm64: Fix handling of FEAT_GTG for unimplemented granule sizes
  KVM: arm64: Don't free hyp pages with pKVM on GICv2
  KVM: arm64: Fix error path in init_hyp_mode()
  KVM: arm64: Adjust range correctly during host stage-2 faults
  KVM: arm64: nv: Fix MI line level calculation in vgic_v3_nested_update_mi()
  KVM: x86/hyper-v: Skip non-canonical addresses during PV TLB flush
  KVM: SVM: Add missing member in SNP_LAUNCH_START command structure
  Documentation: KVM: Fix unexpected unindent warnings
  KVM: selftests: Add back the missing check of MONITOR/MWAIT availability
  KVM: Allow CPU to reschedule while setting per-page memory attributes
  KVM: x86/xen: Allow 'out of range' event channel ports in IRQ routing table.
  KVM: x86/hyper-v: Use preallocated per-vCPU buffer for de-sparsified vCPU masks
  KVM: SVM: Initialize vmsa_pa in VMCB to INVALID_PAGE if VMSA page is NULL
  KVM: SVM: Reject SEV{-ES} intra host migration if vCPU creation is in-flight
  KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities
  KVM: TDX: Exit to userspace for SetupEventNotifyInterrupt
2025-07-10 09:06:53 -07:00
Xin Li (Intel)
5f465c148c x86/traps: Initialize DR6 by writing its architectural reset value
Initialize DR6 by writing its architectural reset value to avoid
incorrectly zeroing DR6 to clear DR6.BLD at boot time, which leads
to a false bus lock detected warning.

The Intel SDM says:

  1) Certain debug exceptions may clear bits 0-3 of DR6.

  2) BLD induced #DB clears DR6.BLD and any other debug exception
     doesn't modify DR6.BLD.

  3) RTM induced #DB clears DR6.RTM and any other debug exception
     sets DR6.RTM.

  To avoid confusion in identifying debug exceptions, debug handlers
  should set DR6.BLD and DR6.RTM, and clear other DR6 bits before
  returning.

The DR6 architectural reset value 0xFFFF0FF0, already defined as
macro DR6_RESERVED, satisfies these requirements, so just use it to
reinitialize DR6 whenever needed.

Since clear_all_debug_regs() no longer zeros all debug registers,
rename it to initialize_debug_regs() to better reflect its current
behavior.

Since debug_read_clear_dr6() no longer clears DR6, rename it to
debug_read_reset_dr6() to better reflect its current behavior.

Fixes: ebb1064e7c ("x86/traps: Handle #DB for bus lock")
Reported-by: Sohil Mehta <sohil.mehta@intel.com>
Suggested-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/lkml/06e68373-a92b-472e-8fd9-ba548119770c@intel.com/
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250620231504.2676902-2-xin%40zytor.com
2025-06-24 13:15:51 -07:00
Paolo Bonzini
28224ef02b KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities
Allow userspace to advertise TDG.VP.VMCALL subfunctions that the
kernel also supports.  For each output register of GetTdVmCallInfo's
leaf 1, add two fields to KVM_TDX_CAPABILITIES: one for kernel-supported
TDVMCALLs (userspace can set those blindly) and one for user-supported
TDVMCALLs (userspace can set those if it knows how to handle them).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-06-20 14:20:20 -04:00
Linus Torvalds
7f9039c524 Generic:
* Clean up locking of all vCPUs for a VM by using the *_nest_lock()
   family of functions, and move duplicated code to virt/kvm/.
   kernel/ patches acked by Peter Zijlstra.
 
 * Add MGLRU support to the access tracking perf test.
 
 ARM fixes:
 
 * Make the irqbypass hooks resilient to changes in the GSI<->MSI
   routing, avoiding behind stale vLPI mappings being left behind. The
   fix is to resolve the VGIC IRQ using the host IRQ (which is stable)
   and nuking the vLPI mapping upon a routing change.
 
 * Close another VGIC race where vCPU creation races with VGIC
   creation, leading to in-flight vCPUs entering the kernel w/o private
   IRQs allocated.
 
 * Fix a build issue triggered by the recently added workaround for
   Ampere's AC04_CPU_23 erratum.
 
 * Correctly sign-extend the VA when emulating a TLBI instruction
   potentially targeting a VNCR mapping.
 
 * Avoid dereferencing a NULL pointer in the VGIC debug code, which can
   happen if the device doesn't have any mapping yet.
 
 s390:
 
 * Fix interaction between some filesystems and Secure Execution
 
 * Some cleanups and refactorings, preparing for an upcoming big series
 
 x86:
 
 * Wait for target vCPU to acknowledge KVM_REQ_UPDATE_PROTECTED_GUEST_STATE to
   fix a race between AP destroy and VMRUN.
 
 * Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for the VM.
 
 * Refine and harden handling of spurious faults.
 
 * Add support for ALLOWED_SEV_FEATURES.
 
 * Add #VMGEXIT to the set of handlers special cased for CONFIG_RETPOLINE=y.
 
 * Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing features
   that utilize those bits.
 
 * Don't account temporary allocations in sev_send_update_data().
 
 * Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock Threshold.
 
 * Unify virtualization of IBRS on nested VM-Exit, and cross-vCPU IBPB, between
   SVM and VMX.
 
 * Advertise support to userspace for WRMSRNS and PREFETCHI.
 
 * Rescan I/O APIC routes after handling EOI that needed to be intercepted due
   to the old/previous routing, but not the new/current routing.
 
 * Add a module param to control and enumerate support for device posted
   interrupts.
 
 * Fix a potential overflow with nested virt on Intel systems running 32-bit kernels.
 
 * Flush shadow VMCSes on emergency reboot.
 
 * Add support for SNP to the various SEV selftests.
 
 * Add a selftest to verify fastops instructions via forced emulation.
 
 * Refine and optimize KVM's software processing of the posted interrupt bitmap, and share
   the harvesting code between KVM and the kernel's Posted MSI handler
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull more kvm updates from Paolo Bonzini:
  Generic:

   - Clean up locking of all vCPUs for a VM by using the *_nest_lock()
     family of functions, and move duplicated code to virt/kvm/. kernel/
     patches acked by Peter Zijlstra

   - Add MGLRU support to the access tracking perf test

  ARM fixes:

   - Make the irqbypass hooks resilient to changes in the GSI<->MSI
     routing, avoiding behind stale vLPI mappings being left behind. The
     fix is to resolve the VGIC IRQ using the host IRQ (which is stable)
     and nuking the vLPI mapping upon a routing change

   - Close another VGIC race where vCPU creation races with VGIC
     creation, leading to in-flight vCPUs entering the kernel w/o
     private IRQs allocated

   - Fix a build issue triggered by the recently added workaround for
     Ampere's AC04_CPU_23 erratum

   - Correctly sign-extend the VA when emulating a TLBI instruction
     potentially targeting a VNCR mapping

   - Avoid dereferencing a NULL pointer in the VGIC debug code, which
     can happen if the device doesn't have any mapping yet

  s390:

   - Fix interaction between some filesystems and Secure Execution

   - Some cleanups and refactorings, preparing for an upcoming big
     series

  x86:

   - Wait for target vCPU to ack KVM_REQ_UPDATE_PROTECTED_GUEST_STATE
     to fix a race between AP destroy and VMRUN

   - Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for
     the VM

   - Refine and harden handling of spurious faults

   - Add support for ALLOWED_SEV_FEATURES

   - Add #VMGEXIT to the set of handlers special cased for
     CONFIG_RETPOLINE=y

   - Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing
     features that utilize those bits

   - Don't account temporary allocations in sev_send_update_data()

   - Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock
     Threshold

   - Unify virtualization of IBRS on nested VM-Exit, and cross-vCPU
     IBPB, between SVM and VMX

   - Advertise support to userspace for WRMSRNS and PREFETCHI

   - Rescan I/O APIC routes after handling EOI that needed to be
     intercepted due to the old/previous routing, but not the
     new/current routing

   - Add a module param to control and enumerate support for device
     posted interrupts

   - Fix a potential overflow with nested virt on Intel systems running
     32-bit kernels

   - Flush shadow VMCSes on emergency reboot

   - Add support for SNP to the various SEV selftests

   - Add a selftest to verify fastops instructions via forced emulation

   - Refine and optimize KVM's software processing of the posted
     interrupt bitmap, and share the harvesting code between KVM and the
     kernel's Posted MSI handler"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (93 commits)
  rtmutex_api: provide correct extern functions
  KVM: arm64: vgic-debug: Avoid dereferencing NULL ITE pointer
  KVM: arm64: vgic-init: Plug vCPU vs. VGIC creation race
  KVM: arm64: Unmap vLPIs affected by changes to GSI routing information
  KVM: arm64: Resolve vLPI by host IRQ in vgic_v4_unset_forwarding()
  KVM: arm64: Protect vLPI translation with vgic_irq::irq_lock
  KVM: arm64: Use lock guard in vgic_v4_set_forwarding()
  KVM: arm64: Mask out non-VA bits from TLBI VA* on VNCR invalidation
  arm64: sysreg: Drag linux/kconfig.h to work around vdso build issue
  KVM: s390: Simplify and move pv code
  KVM: s390: Refactor and split some gmap helpers
  KVM: s390: Remove unneeded srcu lock
  s390: Remove unneeded includes
  s390/uv: Improve splitting of large folios that cannot be split while dirty
  s390/uv: Always return 0 from s390_wiggle_split_folio() if successful
  s390/uv: Don't return 0 from make_hva_secure() if the operation was not successful
  rust: add helper for mutex_trylock
  RISC-V: KVM: use kvm_trylock_all_vcpus when locking all vCPUs
  KVM: arm64: use kvm_trylock_all_vcpus when locking all vCPUs
  x86: KVM: SVM: use kvm_lock_all_vcpus instead of a custom implementation
  ...
2025-06-02 12:24:58 -07:00
Linus Torvalds
00c010e130 - The 11 patch series "Add folio_mk_pte()" from Matthew Wilcox
simplifies the act of creating a pte which addresses the first page in a
   folio and reduces the amount of plumbing which architecture must
   implement to provide this.
 
 - The 8 patch series "Misc folio patches for 6.16" from Matthew Wilcox
   is a shower of largely unrelated folio infrastructure changes which
   clean things up and better prepare us for future work.
 
 - The 3 patch series "memory,x86,acpi: hotplug memory alignment
   advisement" from Gregory Price adds early-init code to prevent x86 from
   leaving physical memory unused when physical address regions are not
   aligned to memory block size.
 
 - The 2 patch series "mm/compaction: allow more aggressive proactive
   compaction" from Michal Clapinski provides some tuning of the (sadly,
   hard-coded (more sadly, not auto-tuned)) thresholds for our invokation
   of proactive compaction.  In a simple test case, the reduction of a guest
   VM's memory consumption was dramatic.
 
 - The 8 patch series "Minor cleanups and improvements to swap freeing
   code" from Kemeng Shi provides some code cleaups and a small efficiency
   improvement to this part of our swap handling code.
 
 - The 6 patch series "ptrace: introduce PTRACE_SET_SYSCALL_INFO API"
   from Dmitry Levin adds the ability for a ptracer to modify syscalls
   arguments.  At this time we can alter only "system call information that
   are used by strace system call tampering, namely, syscall number,
   syscall arguments, and syscall return value.
 
   This series should have been incorporated into mm.git's "non-MM"
   branch, but I goofed.
 
 - The 3 patch series "fs/proc: extend the PAGEMAP_SCAN ioctl to report
   guard regions" from Andrei Vagin extends the info returned by the
   PAGEMAP_SCAN ioctl against /proc/pid/pagemap.  This permits CRIU to more
   efficiently get at the info about guard regions.
 
 - The 2 patch series "Fix parameter passed to page_mapcount_is_type()"
   from Gavin Shan implements that fix.  No runtime effect is expected
   because validate_page_before_insert() happens to fix up this error.
 
 - The 3 patch series "kernel/events/uprobes: uprobe_write_opcode()
   rewrite" from David Hildenbrand basically brings uprobe text poking into
   the current decade.  Remove a bunch of hand-rolled implementation in
   favor of using more current facilities.
 
 - The 3 patch series "mm/ptdump: Drop assumption that pxd_val() is u64"
   from Anshuman Khandual provides enhancements and generalizations to the
   pte dumping code.  This might be needed when 128-bit Page Table
   Descriptors are enabled for ARM.
 
 - The 12 patch series "Always call constructor for kernel page tables"
   from Kevin Brodsky "ensures that the ctor/dtor is always called for
   kernel pgtables, as it already is for user pgtables".  This permits the
   addition of more functionality such as "insert hooks to protect page
   tables".  This change does result in various architectures performing
   unnecesary work, but this is fixed up where it is anticipated to occur.
 
 - The 9 patch series "Rust support for mm_struct, vm_area_struct, and
   mmap" from Alice Ryhl adds plumbing to permit Rust access to core MM
   structures.
 
 - The 3 patch series "fix incorrectly disallowed anonymous VMA merges"
   from Lorenzo Stoakes takes advantage of some VMA merging opportunities
   which we've been missing for 15 years.
 
 - The 4 patch series "mm/madvise: batch tlb flushes for MADV_DONTNEED
   and MADV_FREE" from SeongJae Park optimizes process_madvise()'s TLB
   flushing.  Instead of flushing each address range in the provided iovec,
   we batch the flushing across all the iovec entries.  The syscall's cost
   was approximately halved with a microbenchmark which was designed to
   load this particular operation.
 
 - The 6 patch series "Track node vacancy to reduce worst case allocation
   counts" from Sidhartha Kumar makes the maple tree smarter about its node
   preallocation.  stress-ng mmap performance increased by single-digit
   percentages and the amount of unnecessarily preallocated memory was
   dramaticelly reduced.
 
 - The 3 patch series "mm/gup: Minor fix, cleanup and improvements" from
   Baoquan He removes a few unnecessary things which Baoquan noted when
   reading the code.
 
 - The 3 patch series ""Enhance sysfs handling for memory hotplug in
   weighted interleave" from Rakie Kim "enhances the weighted interleave
   policy in the memory management subsystem by improving sysfs handling,
   fixing memory leaks, and introducing dynamic sysfs updates for memory
   hotplug support".  Fixes things on error paths which we are unlikely to
   hit.
 
 - The 7 patch series "mm/damon: auto-tune DAMOS for NUMA setups
   including tiered memory" from SeongJae Park introduces new DAMOS quota
   goal metrics which eliminate the manual tuning which is required when
   utilizing DAMON for memory tiering.
 
 - The 5 patch series "mm/vmalloc.c: code cleanup and improvements" from
   Baoquan He provides cleanups and small efficiency improvements which
   Baoquan found via code inspection.
 
 - The 2 patch series "vmscan: enforce mems_effective during demotion"
   from Gregory Price "changes reclaim to respect cpuset.mems_effective
   during demotion when possible".  because "presently, reclaim explicitly
   ignores cpuset.mems_effective when demoting, which may cause the cpuset
   settings to violated." "This is useful for isolating workloads on a
   multi-tenant system from certain classes of memory more consistently."
 
 - The 2 patch series ""Clean up split_huge_pmd_locked() and remove
   unnecessary folio pointers" from Gavin Guo provides minor cleanups and
   efficiency gains in in the huge page splitting and migrating code.
 
 - The 3 patch series "Use kmem_cache for memcg alloc" from Huan Yang
   creates a slab cache for `struct mem_cgroup', yielding improved memory
   utilization.
 
 - The 4 patch series "add max arg to swappiness in memory.reclaim and
   lru_gen" from Zhongkun He adds a new "max" argument to the "swappiness="
   argument for memory.reclaim MGLRU's lru_gen.  This directs proactive
   reclaim to reclaim from only anon folios rather than file-backed folios.
 
 - The 17 patch series "kexec: introduce Kexec HandOver (KHO)" from Mike
   Rapoport is the first step on the path to permitting the kernel to
   maintain existing VMs while replacing the host kernel via file-based
   kexec.  At this time only memblock's reserve_mem is preserved.
 
 - The 7 patch series "mm: Introduce for_each_valid_pfn()" from David
   Woodhouse provides and uses a smarter way of looping over a pfn range.
   By skipping ranges of invalid pfns.
 
 - The 2 patch series "sched/numa: Skip VMA scanning on memory pinned to
   one NUMA node via cpuset.mems" from Libo Chen removes a lot of pointless
   VMA scanning when a task is pinned a single NUMA mode.  Dramatic
   performance benefits were seen in some real world cases.
 
 - The 2 patch series "JFS: Implement migrate_folio for
   jfs_metapage_aops" from Shivank Garg addresses a warning which occurs
   during memory compaction when using JFS.
 
 - The 4 patch series "move all VMA allocation, freeing and duplication
   logic to mm" from Lorenzo Stoakes moves some VMA code from kernel/fork.c
   into the more appropriate mm/vma.c.
 
 - The 6 patch series "mm, swap: clean up swap cache mapping helper" from
   Kairui Song provides code consolidation and cleanups related to the
   folio_index() function.
 
 - The 2 patch series "mm/gup: Cleanup memfd_pin_folios()" from Vishal
   Moola does that.
 
 - The 8 patch series "memcg: Fix test_memcg_min/low test failures" from
   Waiman Long addresses some bogus failures which are being reported by
   the test_memcontrol selftest.
 
 - The 3 patch series "eliminate mmap() retry merge, add .mmap_prepare
   hook" from Lorenzo Stoakes commences the deprecation of
   file_operations.mmap() in favor of the new
   file_operations.mmap_prepare().  The latter is more restrictive and
   prevents drivers from messing with things in ways which, amongst other
   problems, may defeat VMA merging.
 
 - The 4 patch series "memcg: decouple memcg and objcg stocks"" from
   Shakeel Butt decouples the per-cpu memcg charge cache from the objcg's
   one.  This is a step along the way to making memcg and objcg charging
   NMI-safe, which is a BPF requirement.
 
 - The 6 patch series "mm/damon: minor fixups and improvements for code,
   tests, and documents" from SeongJae Park is "yet another batch of
   miscellaneous DAMON changes.  Fix and improve minor problems in code,
   tests and documents."
 
 - The 7 patch series "memcg: make memcg stats irq safe" from Shakeel
   Butt converts memcg stats to be irq safe.  Another step along the way to
   making memcg charging and stats updates NMI-safe, a BPF requirement.
 
 - The 4 patch series "Let unmap_hugepage_range() and several related
   functions take folio instead of page" from Fan Ni provides folio
   conversions in the hugetlb code.
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Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of
   creating a pte which addresses the first page in a folio and reduces
   the amount of plumbing which architecture must implement to provide
   this.

 - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of
   largely unrelated folio infrastructure changes which clean things up
   and better prepare us for future work.

 - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory
   Price adds early-init code to prevent x86 from leaving physical
   memory unused when physical address regions are not aligned to memory
   block size.

 - "mm/compaction: allow more aggressive proactive compaction" from
   Michal Clapinski provides some tuning of the (sadly, hard-coded (more
   sadly, not auto-tuned)) thresholds for our invokation of proactive
   compaction. In a simple test case, the reduction of a guest VM's
   memory consumption was dramatic.

 - "Minor cleanups and improvements to swap freeing code" from Kemeng
   Shi provides some code cleaups and a small efficiency improvement to
   this part of our swap handling code.

 - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin
   adds the ability for a ptracer to modify syscalls arguments. At this
   time we can alter only "system call information that are used by
   strace system call tampering, namely, syscall number, syscall
   arguments, and syscall return value.

   This series should have been incorporated into mm.git's "non-MM"
   branch, but I goofed.

 - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from
   Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl
   against /proc/pid/pagemap. This permits CRIU to more efficiently get
   at the info about guard regions.

 - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan
   implements that fix. No runtime effect is expected because
   validate_page_before_insert() happens to fix up this error.

 - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David
   Hildenbrand basically brings uprobe text poking into the current
   decade. Remove a bunch of hand-rolled implementation in favor of
   using more current facilities.

 - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman
   Khandual provides enhancements and generalizations to the pte dumping
   code. This might be needed when 128-bit Page Table Descriptors are
   enabled for ARM.

 - "Always call constructor for kernel page tables" from Kevin Brodsky
   ensures that the ctor/dtor is always called for kernel pgtables, as
   it already is for user pgtables.

   This permits the addition of more functionality such as "insert hooks
   to protect page tables". This change does result in various
   architectures performing unnecesary work, but this is fixed up where
   it is anticipated to occur.

 - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice
   Ryhl adds plumbing to permit Rust access to core MM structures.

 - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo
   Stoakes takes advantage of some VMA merging opportunities which we've
   been missing for 15 years.

 - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from
   SeongJae Park optimizes process_madvise()'s TLB flushing.

   Instead of flushing each address range in the provided iovec, we
   batch the flushing across all the iovec entries. The syscall's cost
   was approximately halved with a microbenchmark which was designed to
   load this particular operation.

 - "Track node vacancy to reduce worst case allocation counts" from
   Sidhartha Kumar makes the maple tree smarter about its node
   preallocation.

   stress-ng mmap performance increased by single-digit percentages and
   the amount of unnecessarily preallocated memory was dramaticelly
   reduced.

 - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes
   a few unnecessary things which Baoquan noted when reading the code.

 - ""Enhance sysfs handling for memory hotplug in weighted interleave"
   from Rakie Kim "enhances the weighted interleave policy in the memory
   management subsystem by improving sysfs handling, fixing memory
   leaks, and introducing dynamic sysfs updates for memory hotplug
   support". Fixes things on error paths which we are unlikely to hit.

 - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory"
   from SeongJae Park introduces new DAMOS quota goal metrics which
   eliminate the manual tuning which is required when utilizing DAMON
   for memory tiering.

 - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He
   provides cleanups and small efficiency improvements which Baoquan
   found via code inspection.

 - "vmscan: enforce mems_effective during demotion" from Gregory Price
   changes reclaim to respect cpuset.mems_effective during demotion when
   possible. because presently, reclaim explicitly ignores
   cpuset.mems_effective when demoting, which may cause the cpuset
   settings to violated.

   This is useful for isolating workloads on a multi-tenant system from
   certain classes of memory more consistently.

 - "Clean up split_huge_pmd_locked() and remove unnecessary folio
   pointers" from Gavin Guo provides minor cleanups and efficiency gains
   in in the huge page splitting and migrating code.

 - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache
   for `struct mem_cgroup', yielding improved memory utilization.

 - "add max arg to swappiness in memory.reclaim and lru_gen" from
   Zhongkun He adds a new "max" argument to the "swappiness=" argument
   for memory.reclaim MGLRU's lru_gen.

   This directs proactive reclaim to reclaim from only anon folios
   rather than file-backed folios.

 - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the
   first step on the path to permitting the kernel to maintain existing
   VMs while replacing the host kernel via file-based kexec. At this
   time only memblock's reserve_mem is preserved.

 - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides
   and uses a smarter way of looping over a pfn range. By skipping
   ranges of invalid pfns.

 - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via
   cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning
   when a task is pinned a single NUMA mode.

   Dramatic performance benefits were seen in some real world cases.

 - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank
   Garg addresses a warning which occurs during memory compaction when
   using JFS.

 - "move all VMA allocation, freeing and duplication logic to mm" from
   Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more
   appropriate mm/vma.c.

 - "mm, swap: clean up swap cache mapping helper" from Kairui Song
   provides code consolidation and cleanups related to the folio_index()
   function.

 - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that.

 - "memcg: Fix test_memcg_min/low test failures" from Waiman Long
   addresses some bogus failures which are being reported by the
   test_memcontrol selftest.

 - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo
   Stoakes commences the deprecation of file_operations.mmap() in favor
   of the new file_operations.mmap_prepare().

   The latter is more restrictive and prevents drivers from messing with
   things in ways which, amongst other problems, may defeat VMA merging.

 - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples
   the per-cpu memcg charge cache from the objcg's one.

   This is a step along the way to making memcg and objcg charging
   NMI-safe, which is a BPF requirement.

 - "mm/damon: minor fixups and improvements for code, tests, and
   documents" from SeongJae Park is yet another batch of miscellaneous
   DAMON changes. Fix and improve minor problems in code, tests and
   documents.

 - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg
   stats to be irq safe. Another step along the way to making memcg
   charging and stats updates NMI-safe, a BPF requirement.

 - "Let unmap_hugepage_range() and several related functions take folio
   instead of page" from Fan Ni provides folio conversions in the
   hugetlb code.

* tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits)
  mm: pcp: increase pcp->free_count threshold to trigger free_high
  mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range()
  mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page
  mm/hugetlb: pass folio instead of page to unmap_ref_private()
  memcg: objcg stock trylock without irq disabling
  memcg: no stock lock for cpu hot-unplug
  memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs
  memcg: make count_memcg_events re-entrant safe against irqs
  memcg: make mod_memcg_state re-entrant safe against irqs
  memcg: move preempt disable to callers of memcg_rstat_updated
  memcg: memcg_rstat_updated re-entrant safe against irqs
  mm: khugepaged: decouple SHMEM and file folios' collapse
  selftests/eventfd: correct test name and improve messages
  alloc_tag: check mem_profiling_support in alloc_tag_init
  Docs/damon: update titles and brief introductions to explain DAMOS
  selftests/damon/_damon_sysfs: read tried regions directories in order
  mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject()
  mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat()
  mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs
  ...
2025-05-31 15:44:16 -07:00
Paolo Bonzini
4e02d4f973 KVM SVM changes for 6.16:
- Wait for target vCPU to acknowledge KVM_REQ_UPDATE_PROTECTED_GUEST_STATE to
    fix a race between AP destroy and VMRUN.
 
  - Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for the VM.
 
  - Add support for ALLOWED_SEV_FEATURES.
 
  - Add #VMGEXIT to the set of handlers special cased for CONFIG_RETPOLINE=y.
 
  - Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing features
    that utilize those bits.
 
  - Don't account temporary allocations in sev_send_update_data().
 
  - Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock Threshold.
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Merge tag 'kvm-x86-svm-6.16' of https://github.com/kvm-x86/linux into HEAD

KVM SVM changes for 6.16:

 - Wait for target vCPU to acknowledge KVM_REQ_UPDATE_PROTECTED_GUEST_STATE to
   fix a race between AP destroy and VMRUN.

 - Decrypt and dump the VMSA in dump_vmcb() if debugging enabled for the VM.

 - Add support for ALLOWED_SEV_FEATURES.

 - Add #VMGEXIT to the set of handlers special cased for CONFIG_RETPOLINE=y.

 - Treat DEBUGCTL[5:2] as reserved to pave the way for virtualizing features
   that utilize those bits.

 - Don't account temporary allocations in sev_send_update_data().

 - Add support for KVM_CAP_X86_BUS_LOCK_EXIT on SVM, via Bus Lock Threshold.
2025-05-27 12:15:49 -04:00
Nikunj A Dadhania
827547bc3a KVM: SVM: Add architectural definitions/assets for Bus Lock Threshold
Virtual machines can exploit bus locks to degrade the performance of
the system. Bus locks can be caused by Non-WB(Write back) and
misaligned locked RMW (Read-modify-Write) instructions and require
systemwide synchronization among all processors which can result into
significant performance penalties.

To address this issue, the Bus Lock Threshold feature is introduced to
provide ability to hypervisor to restrict guests' capability of
initiating mulitple buslocks, thereby preventing system slowdowns.

Support for the buslock threshold is indicated via CPUID function
0x8000000A_EDX[29].

On the processors that support the Bus Lock Threshold feature, the
VMCB provides a Bus Lock Threshold enable bit and an unsigned 16-bit
Bus Lock threshold count.

VMCB intercept bit
VMCB Offset     Bits    Function
14h             5       Intercept bus lock operations

Bus lock threshold count
VMCB Offset     Bits    Function
120h            15:0    Bus lock counter

When a VMRUN instruction is executed, the bus lock threshold count is
loaded into an internal count register. Before the processor executes
a bus lock in the guest, it checks the value of this register:

 - If the value is greater than '0', the processor successfully
   executes the bus lock and decrements the count.

 - If the value is '0', the bus lock is not executed, and a #VMEXIT to
   the VMM is taken.

The bus lock threshold #VMEXIT is reported to the VMM with the VMEXIT
code A5h, SVM_EXIT_BUS_LOCK.

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Co-developed-by: Manali Shukla <manali.shukla@amd.com>
Signed-off-by: Manali Shukla <manali.shukla@amd.com>
Link: https://lore.kernel.org/r/20250502050346.14274-4-manali.shukla@amd.com
[sean: rewrite shortlog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-05-16 09:42:08 -07:00
Alexander Graf
65a5d72785 x86/kexec: add support for passing kexec handover (KHO) data
kexec handover (KHO) creates a metadata that the kernels pass between each
other during kexec.  This metadata is stored in memory and kexec image
contains a (physical) pointer to that memory.

In addition, KHO keeps "scratch regions" available for kexec: physically
contiguous memory regions that are guaranteed to not have any memory that
KHO would preserve.  The new kernel bootstraps itself using the scratch
regions and sets all handed over memory as in use.  When subsystems that
support KHO initialize, they introspect the KHO metadata, restore
preserved memory regions, and retrieve their state stored in the preserved
memory.

Enlighten x86 kexec-file and boot path about the KHO metadata and make
sure it gets passed along to the next kernel.

Link: https://lkml.kernel.org/r/20250509074635.3187114-12-changyuanl@google.com
Signed-off-by: Alexander Graf <graf@amazon.com>
Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Co-developed-by: Changyuan Lyu <changyuanl@google.com>
Signed-off-by: Changyuan Lyu <changyuanl@google.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anthony Yznaga <anthony.yznaga@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ashish Kalra <ashish.kalra@amd.com>
Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Gowans <jgowans@amazon.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Pratyush Yadav <ptyadav@amazon.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Lendacky <thomas.lendacky@amd.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-05-12 23:50:41 -07:00
Pratik R. Sampat
3bf3e0a521 KVM: selftests: Add library support for interacting with SNP
Extend the SEV library to include support for SNP ioctl() wrappers,
which aid in launching and interacting with a SEV-SNP guest.

Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
Link: https://lore.kernel.org/r/20250305230000.231025-8-prsampat@amd.com
[sean: use BIT()]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-05-02 12:32:33 -07:00
Paolo Bonzini
fd02aa45bd Merge branch 'kvm-tdx-initial' into HEAD
This large commit contains the initial support for TDX in KVM.  All x86
parts enable the host-side hypercalls that KVM uses to talk to the TDX
module, a software component that runs in a special CPU mode called SEAM
(Secure Arbitration Mode).

The series is in turn split into multiple sub-series, each with a separate
merge commit:

- Initialization: basic setup for using the TDX module from KVM, plus
  ioctls to create TDX VMs and vCPUs.

- MMU: in TDX, private and shared halves of the address space are mapped by
  different EPT roots, and the private half is managed by the TDX module.
  Using the support that was added to the generic MMU code in 6.14,
  add support for TDX's secure page tables to the Intel side of KVM.
  Generic KVM code takes care of maintaining a mirror of the secure page
  tables so that they can be queried efficiently, and ensuring that changes
  are applied to both the mirror and the secure EPT.

- vCPU enter/exit: implement the callbacks that handle the entry of a TDX
  vCPU (via the SEAMCALL TDH.VP.ENTER) and the corresponding save/restore
  of host state.

- Userspace exits: introduce support for guest TDVMCALLs that KVM forwards to
  userspace.  These correspond to the usual KVM_EXIT_* "heavyweight vmexits"
  but are triggered through a different mechanism, similar to VMGEXIT for
  SEV-ES and SEV-SNP.

- Interrupt handling: support for virtual interrupt injection as well as
  handling VM-Exits that are caused by vectored events.  Exclusive to
  TDX are machine-check SMIs, which the kernel already knows how to
  handle through the kernel machine check handler (commit 7911f145de,
  "x86/mce: Implement recovery for errors in TDX/SEAM non-root mode")

- Loose ends: handling of the remaining exits from the TDX module, including
  EPT violation/misconfig and several TDVMCALL leaves that are handled in
  the kernel (CPUID, HLT, RDMSR/WRMSR, GetTdVmCallInfo); plus returning
  an error or ignoring operations that are not supported by TDX guests

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-04-07 07:36:33 -04:00
Linus Torvalds
edb0e8f6e2 ARM:
* Nested virtualization support for VGICv3, giving the nested
 hypervisor control of the VGIC hardware when running an L2 VM
 
 * Removal of 'late' nested virtualization feature register masking,
   making the supported feature set directly visible to userspace
 
 * Support for emulating FEAT_PMUv3 on Apple silicon, taking advantage
   of an IMPLEMENTATION DEFINED trap that covers all PMUv3 registers
 
 * Paravirtual interface for discovering the set of CPU implementations
   where a VM may run, addressing a longstanding issue of guest CPU
   errata awareness in big-little systems and cross-implementation VM
   migration
 
 * Userspace control of the registers responsible for identifying a
   particular CPU implementation (MIDR_EL1, REVIDR_EL1, AIDR_EL1),
   allowing VMs to be migrated cross-implementation
 
 * pKVM updates, including support for tracking stage-2 page table
   allocations in the protected hypervisor in the 'SecPageTable' stat
 
 * Fixes to vPMU, ensuring that userspace updates to the vPMU after
   KVM_RUN are reflected into the backing perf events
 
 LoongArch:
 
 * Remove unnecessary header include path
 
 * Assume constant PGD during VM context switch
 
 * Add perf events support for guest VM
 
 RISC-V:
 
 * Disable the kernel perf counter during configure
 
 * KVM selftests improvements for PMU
 
 * Fix warning at the time of KVM module removal
 
 x86:
 
 * Add support for aging of SPTEs without holding mmu_lock.  Not taking mmu_lock
   allows multiple aging actions to run in parallel, and more importantly avoids
   stalling vCPUs.  This includes an implementation of per-rmap-entry locking;
   aging the gfn is done with only a per-rmap single-bin spinlock taken, whereas
   locking an rmap for write requires taking both the per-rmap spinlock and
   the mmu_lock.
 
   Note that this decreases slightly the accuracy of accessed-page information,
   because changes to the SPTE outside aging might not use atomic operations
   even if they could race against a clear of the Accessed bit.  This is
   deliberate because KVM and mm/ tolerate false positives/negatives for
   accessed information, and testing has shown that reducing the latency of
   aging is far more beneficial to overall system performance than providing
   "perfect" young/old information.
 
 * Defer runtime CPUID updates until KVM emulates a CPUID instruction, to
   coalesce updates when multiple pieces of vCPU state are changing, e.g. as
   part of a nested transition.
 
 * Fix a variety of nested emulation bugs, and add VMX support for synthesizing
   nested VM-Exit on interception (instead of injecting #UD into L2).
 
 * Drop "support" for async page faults for protected guests that do not set
   SEND_ALWAYS (i.e. that only want async page faults at CPL3)
 
 * Bring a bit of sanity to x86's VM teardown code, which has accumulated
   a lot of cruft over the years.  Particularly, destroy vCPUs before
   the MMU, despite the latter being a VM-wide operation.
 
 * Add common secure TSC infrastructure for use within SNP and in the
   future TDX
 
 * Block KVM_CAP_SYNC_REGS if guest state is protected.  It does not make
   sense to use the capability if the relevant registers are not
   available for reading or writing.
 
 * Don't take kvm->lock when iterating over vCPUs in the suspend notifier to
   fix a largely theoretical deadlock.
 
 * Use the vCPU's actual Xen PV clock information when starting the Xen timer,
   as the cached state in arch.hv_clock can be stale/bogus.
 
 * Fix a bug where KVM could bleed PVCLOCK_GUEST_STOPPED across different
   PV clocks; restrict PVCLOCK_GUEST_STOPPED to kvmclock, as KVM's suspend
   notifier only accounts for kvmclock, and there's no evidence that the
   flag is actually supported by Xen guests.
 
 * Clean up the per-vCPU "cache" of its reference pvclock, and instead only
   track the vCPU's TSC scaling (multipler+shift) metadata (which is moderately
   expensive to compute, and rarely changes for modern setups).
 
 * Don't write to the Xen hypercall page on MSR writes that are initiated by
   the host (userspace or KVM) to fix a class of bugs where KVM can write to
   guest memory at unexpected times, e.g. during vCPU creation if userspace has
   set the Xen hypercall MSR index to collide with an MSR that KVM emulates.
 
 * Restrict the Xen hypercall MSR index to the unofficial synthetic range to
   reduce the set of possible collisions with MSRs that are emulated by KVM
   (collisions can still happen as KVM emulates Hyper-V MSRs, which also reside
   in the synthetic range).
 
 * Clean up and optimize KVM's handling of Xen MSR writes and xen_hvm_config.
 
 * Update Xen TSC leaves during CPUID emulation instead of modifying the CPUID
   entries when updating PV clocks; there is no guarantee PV clocks will be
   updated between TSC frequency changes and CPUID emulation, and guest reads
   of the TSC leaves should be rare, i.e. are not a hot path.
 
 x86 (Intel):
 
 * Fix a bug where KVM unnecessarily reads XFD_ERR from hardware and thus
   modifies the vCPU's XFD_ERR on a #NM due to CR0.TS=1.
 
 * Pass XFD_ERR as the payload when injecting #NM, as a preparatory step
   for upcoming FRED virtualization support.
 
 * Decouple the EPT entry RWX protection bit macros from the EPT Violation
   bits, both as a general cleanup and in anticipation of adding support for
   emulating Mode-Based Execution Control (MBEC).
 
 * Reject KVM_RUN if userspace manages to gain control and stuff invalid guest
   state while KVM is in the middle of emulating nested VM-Enter.
 
 * Add a macro to handle KVM's sanity checks on entry/exit VMCS control pairs
   in anticipation of adding sanity checks for secondary exit controls (the
   primary field is out of bits).
 
 x86 (AMD):
 
 * Ensure the PSP driver is initialized when both the PSP and KVM modules are
   built-in (the initcall framework doesn't handle dependencies).
 
 * Use long-term pins when registering encrypted memory regions, so that the
   pages are migrated out of MIGRATE_CMA/ZONE_MOVABLE and don't lead to
   excessive fragmentation.
 
 * Add macros and helpers for setting GHCB return/error codes.
 
 * Add support for Idle HLT interception, which elides interception if the vCPU
   has a pending, unmasked virtual IRQ when HLT is executed.
 
 * Fix a bug in INVPCID emulation where KVM fails to check for a non-canonical
   address.
 
 * Don't attempt VMRUN for SEV-ES+ guests if the vCPU's VMSA is invalid, e.g.
   because the vCPU was "destroyed" via SNP's AP Creation hypercall.
 
 * Reject SNP AP Creation if the requested SEV features for the vCPU don't
   match the VM's configured set of features.
 
 Selftests:
 
 * Fix again the Intel PMU counters test; add a data load and do CLFLUSH{OPT} on the data
   instead of executing code.  The theory is that modern Intel CPUs have
   learned new code prefetching tricks that bypass the PMU counters.
 
 * Fix a flaw in the Intel PMU counters test where it asserts that an event is
   counting correctly without actually knowing what the event counts on the
   underlying hardware.
 
 * Fix a variety of flaws, bugs, and false failures/passes dirty_log_test, and
   improve its coverage by collecting all dirty entries on each iteration.
 
 * Fix a few minor bugs related to handling of stats FDs.
 
 * Add infrastructure to make vCPU and VM stats FDs available to tests by
   default (open the FDs during VM/vCPU creation).
 
 * Relax an assertion on the number of HLT exits in the xAPIC IPI test when
   running on a CPU that supports AMD's Idle HLT (which elides interception of
   HLT if a virtual IRQ is pending and unmasked).
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "ARM:

   - Nested virtualization support for VGICv3, giving the nested
     hypervisor control of the VGIC hardware when running an L2 VM

   - Removal of 'late' nested virtualization feature register masking,
     making the supported feature set directly visible to userspace

   - Support for emulating FEAT_PMUv3 on Apple silicon, taking advantage
     of an IMPLEMENTATION DEFINED trap that covers all PMUv3 registers

   - Paravirtual interface for discovering the set of CPU
     implementations where a VM may run, addressing a longstanding issue
     of guest CPU errata awareness in big-little systems and
     cross-implementation VM migration

   - Userspace control of the registers responsible for identifying a
     particular CPU implementation (MIDR_EL1, REVIDR_EL1, AIDR_EL1),
     allowing VMs to be migrated cross-implementation

   - pKVM updates, including support for tracking stage-2 page table
     allocations in the protected hypervisor in the 'SecPageTable' stat

   - Fixes to vPMU, ensuring that userspace updates to the vPMU after
     KVM_RUN are reflected into the backing perf events

  LoongArch:

   - Remove unnecessary header include path

   - Assume constant PGD during VM context switch

   - Add perf events support for guest VM

  RISC-V:

   - Disable the kernel perf counter during configure

   - KVM selftests improvements for PMU

   - Fix warning at the time of KVM module removal

  x86:

   - Add support for aging of SPTEs without holding mmu_lock.

     Not taking mmu_lock allows multiple aging actions to run in
     parallel, and more importantly avoids stalling vCPUs. This includes
     an implementation of per-rmap-entry locking; aging the gfn is done
     with only a per-rmap single-bin spinlock taken, whereas locking an
     rmap for write requires taking both the per-rmap spinlock and the
     mmu_lock.

     Note that this decreases slightly the accuracy of accessed-page
     information, because changes to the SPTE outside aging might not
     use atomic operations even if they could race against a clear of
     the Accessed bit.

     This is deliberate because KVM and mm/ tolerate false
     positives/negatives for accessed information, and testing has shown
     that reducing the latency of aging is far more beneficial to
     overall system performance than providing "perfect" young/old
     information.

   - Defer runtime CPUID updates until KVM emulates a CPUID instruction,
     to coalesce updates when multiple pieces of vCPU state are
     changing, e.g. as part of a nested transition

   - Fix a variety of nested emulation bugs, and add VMX support for
     synthesizing nested VM-Exit on interception (instead of injecting
     #UD into L2)

   - Drop "support" for async page faults for protected guests that do
     not set SEND_ALWAYS (i.e. that only want async page faults at CPL3)

   - Bring a bit of sanity to x86's VM teardown code, which has
     accumulated a lot of cruft over the years. Particularly, destroy
     vCPUs before the MMU, despite the latter being a VM-wide operation

   - Add common secure TSC infrastructure for use within SNP and in the
     future TDX

   - Block KVM_CAP_SYNC_REGS if guest state is protected. It does not
     make sense to use the capability if the relevant registers are not
     available for reading or writing

   - Don't take kvm->lock when iterating over vCPUs in the suspend
     notifier to fix a largely theoretical deadlock

   - Use the vCPU's actual Xen PV clock information when starting the
     Xen timer, as the cached state in arch.hv_clock can be stale/bogus

   - Fix a bug where KVM could bleed PVCLOCK_GUEST_STOPPED across
     different PV clocks; restrict PVCLOCK_GUEST_STOPPED to kvmclock, as
     KVM's suspend notifier only accounts for kvmclock, and there's no
     evidence that the flag is actually supported by Xen guests

   - Clean up the per-vCPU "cache" of its reference pvclock, and instead
     only track the vCPU's TSC scaling (multipler+shift) metadata (which
     is moderately expensive to compute, and rarely changes for modern
     setups)

   - Don't write to the Xen hypercall page on MSR writes that are
     initiated by the host (userspace or KVM) to fix a class of bugs
     where KVM can write to guest memory at unexpected times, e.g.
     during vCPU creation if userspace has set the Xen hypercall MSR
     index to collide with an MSR that KVM emulates

   - Restrict the Xen hypercall MSR index to the unofficial synthetic
     range to reduce the set of possible collisions with MSRs that are
     emulated by KVM (collisions can still happen as KVM emulates
     Hyper-V MSRs, which also reside in the synthetic range)

   - Clean up and optimize KVM's handling of Xen MSR writes and
     xen_hvm_config

   - Update Xen TSC leaves during CPUID emulation instead of modifying
     the CPUID entries when updating PV clocks; there is no guarantee PV
     clocks will be updated between TSC frequency changes and CPUID
     emulation, and guest reads of the TSC leaves should be rare, i.e.
     are not a hot path

  x86 (Intel):

   - Fix a bug where KVM unnecessarily reads XFD_ERR from hardware and
     thus modifies the vCPU's XFD_ERR on a #NM due to CR0.TS=1

   - Pass XFD_ERR as the payload when injecting #NM, as a preparatory
     step for upcoming FRED virtualization support

   - Decouple the EPT entry RWX protection bit macros from the EPT
     Violation bits, both as a general cleanup and in anticipation of
     adding support for emulating Mode-Based Execution Control (MBEC)

   - Reject KVM_RUN if userspace manages to gain control and stuff
     invalid guest state while KVM is in the middle of emulating nested
     VM-Enter

   - Add a macro to handle KVM's sanity checks on entry/exit VMCS
     control pairs in anticipation of adding sanity checks for secondary
     exit controls (the primary field is out of bits)

  x86 (AMD):

   - Ensure the PSP driver is initialized when both the PSP and KVM
     modules are built-in (the initcall framework doesn't handle
     dependencies)

   - Use long-term pins when registering encrypted memory regions, so
     that the pages are migrated out of MIGRATE_CMA/ZONE_MOVABLE and
     don't lead to excessive fragmentation

   - Add macros and helpers for setting GHCB return/error codes

   - Add support for Idle HLT interception, which elides interception if
     the vCPU has a pending, unmasked virtual IRQ when HLT is executed

   - Fix a bug in INVPCID emulation where KVM fails to check for a
     non-canonical address

   - Don't attempt VMRUN for SEV-ES+ guests if the vCPU's VMSA is
     invalid, e.g. because the vCPU was "destroyed" via SNP's AP
     Creation hypercall

   - Reject SNP AP Creation if the requested SEV features for the vCPU
     don't match the VM's configured set of features

  Selftests:

   - Fix again the Intel PMU counters test; add a data load and do
     CLFLUSH{OPT} on the data instead of executing code. The theory is
     that modern Intel CPUs have learned new code prefetching tricks
     that bypass the PMU counters

   - Fix a flaw in the Intel PMU counters test where it asserts that an
     event is counting correctly without actually knowing what the event
     counts on the underlying hardware

   - Fix a variety of flaws, bugs, and false failures/passes
     dirty_log_test, and improve its coverage by collecting all dirty
     entries on each iteration

   - Fix a few minor bugs related to handling of stats FDs

   - Add infrastructure to make vCPU and VM stats FDs available to tests
     by default (open the FDs during VM/vCPU creation)

   - Relax an assertion on the number of HLT exits in the xAPIC IPI test
     when running on a CPU that supports AMD's Idle HLT (which elides
     interception of HLT if a virtual IRQ is pending and unmasked)"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (216 commits)
  RISC-V: KVM: Optimize comments in kvm_riscv_vcpu_isa_disable_allowed
  RISC-V: KVM: Teardown riscv specific bits after kvm_exit
  LoongArch: KVM: Register perf callbacks for guest
  LoongArch: KVM: Implement arch-specific functions for guest perf
  LoongArch: KVM: Add stub for kvm_arch_vcpu_preempted_in_kernel()
  LoongArch: KVM: Remove PGD saving during VM context switch
  LoongArch: KVM: Remove unnecessary header include path
  KVM: arm64: Tear down vGIC on failed vCPU creation
  KVM: arm64: PMU: Reload when resetting
  KVM: arm64: PMU: Reload when user modifies registers
  KVM: arm64: PMU: Fix SET_ONE_REG for vPMC regs
  KVM: arm64: PMU: Assume PMU presence in pmu-emul.c
  KVM: arm64: PMU: Set raw values from user to PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}
  KVM: arm64: Create each pKVM hyp vcpu after its corresponding host vcpu
  KVM: arm64: Factor out pKVM hyp vcpu creation to separate function
  KVM: arm64: Initialize HCRX_EL2 traps in pKVM
  KVM: arm64: Factor out setting HCRX_EL2 traps into separate function
  KVM: x86: block KVM_CAP_SYNC_REGS if guest state is protected
  KVM: x86: Add infrastructure for secure TSC
  KVM: x86: Push down setting vcpu.arch.user_set_tsc
  ...
2025-03-25 14:22:07 -07:00
Paolo Bonzini
3ecf162a31 KVM Xen changes for 6.15
- Don't write to the Xen hypercall page on MSR writes that are initiated by
    the host (userspace or KVM) to fix a class of bugs where KVM can write to
    guest memory at unexpected times, e.g. during vCPU creation if userspace has
    set the Xen hypercall MSR index to collide with an MSR that KVM emulates.
 
  - Restrict the Xen hypercall MSR indx to the unofficial synthetic range to
    reduce the set of possible collisions with MSRs that are emulated by KVM
    (collisions can still happen as KVM emulates Hyper-V MSRs, which also reside
    in the synthetic range).
 
  - Clean up and optimize KVM's handling of Xen MSR writes and xen_hvm_config.
 
  - Update Xen TSC leaves during CPUID emulation instead of modifying the CPUID
    entries when updating PV clocks, as there is no guarantee PV clocks will be
    updated between TSC frequency changes and CPUID emulation, and guest reads
    of Xen TSC should be rare, i.e. are not a hot path.
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Merge tag 'kvm-x86-xen-6.15' of https://github.com/kvm-x86/linux into HEAD

KVM Xen changes for 6.15

 - Don't write to the Xen hypercall page on MSR writes that are initiated by
   the host (userspace or KVM) to fix a class of bugs where KVM can write to
   guest memory at unexpected times, e.g. during vCPU creation if userspace has
   set the Xen hypercall MSR index to collide with an MSR that KVM emulates.

 - Restrict the Xen hypercall MSR indx to the unofficial synthetic range to
   reduce the set of possible collisions with MSRs that are emulated by KVM
   (collisions can still happen as KVM emulates Hyper-V MSRs, which also reside
   in the synthetic range).

 - Clean up and optimize KVM's handling of Xen MSR writes and xen_hvm_config.

 - Update Xen TSC leaves during CPUID emulation instead of modifying the CPUID
   entries when updating PV clocks, as there is no guarantee PV clocks will be
   updated between TSC frequency changes and CPUID emulation, and guest reads
   of Xen TSC should be rare, i.e. are not a hot path.
2025-03-19 09:14:59 -04:00
Thomas Huth
8a141be323 x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI headers
__ASSEMBLY__ is only defined by the Makefile of the kernel, so
this is not really useful for UAPI headers (unless the userspace
Makefile defines it, too). Let's switch to __ASSEMBLER__ which
gets set automatically by the compiler when compiling assembly
code.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Brian Gerst <brgerst@gmail.com>
Link: https://lore.kernel.org/r/20250310104256.123527-1-thuth@redhat.com
2025-03-19 11:30:53 +01:00
Yan Zhao
c9c1e20b4c KVM: x86: Introduce Intel specific quirk KVM_X86_QUIRK_IGNORE_GUEST_PAT
Introduce an Intel specific quirk KVM_X86_QUIRK_IGNORE_GUEST_PAT to have
KVM ignore guest PAT when this quirk is enabled.

On AMD platforms, KVM always honors guest PAT.  On Intel however there are
two issues.  First, KVM *cannot* honor guest PAT if CPU feature self-snoop
is not supported. Second, UC access on certain Intel platforms can be very
slow[1] and honoring guest PAT on those platforms may break some old
guests that accidentally specify video RAM as UC. Those old guests may
never expect the slowness since KVM always forces WB previously. See [2].

So, introduce a quirk that KVM can enable by default on all Intel platforms
to avoid breaking old unmodifiable guests. Newer userspace can disable this
quirk if it wishes KVM to honor guest PAT; disabling the quirk will fail
if self-snoop is not supported, i.e. if KVM cannot obey the wish.

The quirk is a no-op on AMD and also if any assigned devices have
non-coherent DMA.  This is not an issue, as KVM_X86_QUIRK_CD_NW_CLEARED is
another example of a quirk that is sometimes automatically disabled.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/all/Ztl9NWCOupNfVaCA@yzhao56-desk.sh.intel.com # [1]
Link: https://lore.kernel.org/all/87jzfutmfc.fsf@redhat.com # [2]
Message-ID: <20250224070946.31482-1-yan.y.zhao@intel.com>
[Use supported_quirks/inapplicable_quirks to support both AMD and
 no-self-snoop cases, as well as to remove the shadow_memtype_mask check
 from kvm_mmu_may_ignore_guest_pat(). - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:58 -04:00
Isaku Yamahata
6c441e4d6e KVM: TDX: Handle EXIT_REASON_OTHER_SMI
Handle VM exit caused by "other SMI" for TDX, by returning back to
userspace for Machine Check System Management Interrupt (MSMI) case or
ignoring it and resume vCPU for non-MSMI case.

For VMX, SMM transition can happen in both VMX non-root mode and VMX
root mode.  Unlike VMX, in SEAM root mode (TDX module), all interrupts
are blocked. If an SMI occurs in SEAM non-root mode (TD guest), the SMI
causes VM exit to TDX module, then SEAMRET to KVM. Once it exits to KVM,
SMI is delivered and handled by kernel handler right away.

An SMI can be "I/O SMI" or "other SMI".  For TDX, there will be no I/O SMI
because I/O instructions inside TDX guest trigger #VE and TDX guest needs
to use TDVMCALL to request VMM to do I/O emulation.

For "other SMI", there are two cases:
- MSMI case.  When BIOS eMCA MCE-SMI morphing is enabled, the #MC occurs in
  TDX guest will be delivered as an MSMI.  It causes an
  EXIT_REASON_OTHER_SMI VM exit with MSMI (bit 0) set in the exit
  qualification.  On VM exit, TDX module checks whether the "other SMI" is
  caused by an MSMI or not.  If so, TDX module marks TD as fatal,
  preventing further TD entries, and then completes the TD exit flow to KVM
  with the TDH.VP.ENTER outputs indicating TDX_NON_RECOVERABLE_TD.  After
  TD exit, the MSMI is delivered and eventually handled by the kernel
  machine check handler (7911f145de x86/mce: Implement recovery for
  errors in TDX/SEAM non-root mode), i.e., the memory page is marked as
  poisoned and it won't be freed to the free list when the TDX guest is
  terminated.  Since the TDX guest is dead, follow other non-recoverable
  cases, exit to userspace.
- For non-MSMI case, KVM doesn't need to do anything, just continue TDX
  vCPU execution.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Binbin Wu <binbin.wu@linux.intel.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20250222014757.897978-17-binbin.wu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:56 -04:00
Isaku Yamahata
c42856af8f KVM: TDX: Add a place holder for handler of TDX hypercalls (TDG.VP.VMCALL)
Add a place holder and related helper functions for preparation of
TDG.VP.VMCALL handling.

The TDX module specification defines TDG.VP.VMCALL API (TDVMCALL for short)
for the guest TD to call hypercall to VMM.  When the guest TD issues a
TDVMCALL, the guest TD exits to VMM with a new exit reason.  The arguments
from the guest TD and returned values from the VMM are passed in the guest
registers.  The guest RCX register indicates which registers are used.
Define helper functions to access those registers.

A new VMX exit reason TDCALL is added to indicate the exit is due to
TDVMCALL from the guest TD.  Define the TDCALL exit reason and add a place
holder to handle such exit.

Some leafs of TDCALL will be morphed to another VMX exit reason instead of
EXIT_REASON_TDCALL, add a helper tdcall_to_vmx_exit_reason() as a place
holder to do the conversion.

Suggested-by: Sean Christopherson <seanjc@google.com>
Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Binbin Wu <binbin.wu@linux.intel.com>
Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
Message-ID: <20250222014225.897298-5-binbin.wu@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:55 -04:00
Isaku Yamahata
012426d6f5 KVM: TDX: Finalize VM initialization
Add a new VM-scoped KVM_MEMORY_ENCRYPT_OP IOCTL subcommand,
KVM_TDX_FINALIZE_VM, to perform TD Measurement Finalization.

Documentation for the API is added in another patch:
"Documentation/virt/kvm: Document on Trust Domain Extensions(TDX)"

For the purpose of attestation, a measurement must be made of the TDX VM
initial state. This is referred to as TD Measurement Finalization, and
uses SEAMCALL TDH.MR.FINALIZE, after which:
1. The VMM adding TD private pages with arbitrary content is no longer
   allowed
2. The TDX VM is runnable

Co-developed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240904030751.117579-21-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:53 -04:00
Isaku Yamahata
c846b451d3 KVM: TDX: Add an ioctl to create initial guest memory
Add a new ioctl for the user space VMM to initialize guest memory with the
specified memory contents.

Because TDX protects the guest's memory, the creation of the initial guest
memory requires a dedicated TDX module API, TDH.MEM.PAGE.ADD(), instead of
directly copying the memory contents into the guest's memory in the case of
the default VM type.

Define a new subcommand, KVM_TDX_INIT_MEM_REGION, of vCPU-scoped
KVM_MEMORY_ENCRYPT_OP.  Check if the GFN is already pre-allocated, assign
the guest page in Secure-EPT, copy the initial memory contents into the
guest memory, and encrypt the guest memory.  Optionally, extend the memory
measurement of the TDX guest.

The ioctl uses the vCPU file descriptor because of the TDX module's
requirement that the memory is added to the S-EPT (via TDH.MEM.SEPT.ADD)
prior to initialization (TDH.MEM.PAGE.ADD).  Accessing the MMU in turn
requires a vCPU file descriptor, just like for KVM_PRE_FAULT_MEMORY.  In
fact, the post-populate callback is able to reuse the same logic used by
KVM_PRE_FAULT_MEMORY, so that userspace can do everything with a single
ioctl.

Note that this is the only way to invoke TDH.MEM.SEPT.ADD before the TD
in finalized, as userspace cannot use KVM_PRE_FAULT_MEMORY at that
point.  This ensures that there cannot be pages in the S-EPT awaiting
TDH.MEM.PAGE.ADD, which would be treated incorrectly as spurious by
tdp_mmu_map_handle_target_level() (KVM would see the SPTE as PRESENT,
but the corresponding S-EPT entry will be !PRESENT).

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
 - KVM_BUG_ON() for kvm_tdx->nr_premapped (Paolo)
 - Use tdx_operand_busy()
 - Merge first patch in SEPT SEAMCALL retry series in to this base
   (Paolo)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:53 -04:00
Xiaoyao Li
488808e682 KVM: x86: Introduce KVM_TDX_GET_CPUID
Implement an IOCTL to allow userspace to read the CPUID bit values for a
configured TD.

The TDX module doesn't provide the ability to set all CPUID bits. Instead
some are configured indirectly, or have fixed values. But it does allow
for the final resulting CPUID bits to be read. This information will be
useful for userspace to understand the configuration of the TD, and set
KVM's copy via KVM_SET_CPUID2.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Co-developed-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 - Fix subleaf mask check (Binbin)
 - Search all possible sub-leafs (Francesco Lavra)
 - Reduce off-by-one error sensitve code (Francesco, Xiaoyao)
 - Handle buffers too small from userspace (Xiaoyao)
 - Read max CPUID from TD instead of using fixed values (Xiaoyao)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:51 -04:00
Isaku Yamahata
a50f673f25 KVM: TDX: Do TDX specific vcpu initialization
TD guest vcpu needs TDX specific initialization before running.  Repurpose
KVM_MEMORY_ENCRYPT_OP to vcpu-scope, add a new sub-command
KVM_TDX_INIT_VCPU, and implement the callback for it.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Co-developed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 - Fix comment: https://lore.kernel.org/kvm/Z36OYfRW9oPjW8be@google.com/
   (Sean)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:51 -04:00
Isaku Yamahata
0186dd29a2 KVM: TDX: add ioctl to initialize VM with TDX specific parameters
After the crypto-protection key has been configured, TDX requires a
VM-scope initialization as a step of creating the TDX guest.  This
"per-VM" TDX initialization does the global configurations/features that
the TDX guest can support, such as guest's CPUIDs (emulated by the TDX
module), the maximum number of vcpus etc.

Because there is no room in KVM_CREATE_VM to pass all the required
parameters, introduce a new ioctl KVM_TDX_INIT_VM and mark the VM as
TD_STATE_UNINITIALIZED until it is invoked.

This "per-VM" TDX initialization must be done before any "vcpu-scope" TDX
initialization; KVM_TDX_INIT_VM IOCTL must be invoked before the creation
of vCPUs.

Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:51 -04:00
Isaku Yamahata
61bb282796 KVM: TDX: Get system-wide info about TDX module on initialization
TDX KVM needs system-wide information about the TDX module. Generate the
data based on tdx_sysinfo td_conf CPUID data.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Co-developed-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
---
 - Clarify comment about EAX[23:16] in td_init_cpuid_entry2() (Xiaoyao)
 - Add comment for configurable CPUID bits (Xiaoyao)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:50 -04:00
Isaku Yamahata
b2aaf38ced KVM: TDX: Add place holder for TDX VM specific mem_enc_op ioctl
KVM_MEMORY_ENCRYPT_OP was introduced for VM-scoped operations specific for
guest state-protected VM.  It defined subcommands for technology-specific
operations under KVM_MEMORY_ENCRYPT_OP.  Despite its name, the subcommands
are not limited to memory encryption, but various technology-specific
operations are defined.  It's natural to repurpose KVM_MEMORY_ENCRYPT_OP
for TDX specific operations and define subcommands.

Add a place holder function for TDX specific VM-scoped ioctl as mem_enc_op.
TDX specific sub-commands will be added to retrieve/pass TDX specific
parameters.  Make mem_enc_ioctl non-optional as it's always filled.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Co-developed-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Tony Lindgren <tony.lindgren@linux.intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 - Drop the misleading "defined for consistency" line. It's a copy-paste
   error introduced in the earlier patches. Earlier there was padding at
   the end to match struct kvm_sev_cmd size. (Tony)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-14 14:20:50 -04:00
Manali Shukla
fa662c9080 KVM: SVM: Add Idle HLT intercept support
Add support for "Idle HLT" interception on AMD CPUs, and enable Idle HLT
interception instead of "normal" HLT interception for all VMs for which
HLT-exiting is enabled.  Idle HLT provides a mild performance boost for
all VM types, by avoiding a VM-Exit in the scenario where KVM would
immediately "wake" and resume the vCPU.

Idle HLT makes HLT-exiting conditional on the vCPU not having a valid,
unmasked interrupt.  Specifically, a VM-Exit occurs on execution of HLT
if and only if there are no pending V_IRQ or V_NMI events.  Note, Idle
is a replacement for full HLT interception, i.e. enabling HLT interception
would result in all HLT instructions causing unconditional VM-Exits.  Per
the APM:

 When both HLT and Idle HLT intercepts are active at the same time, the
 HLT intercept takes priority. This intercept occurs only if a virtual
 interrupt is not pending (V_INTR or V_NMI).

For KVM's use of V_IRQ (also called V_INTR in the APM) to detect interrupt
windows, the net effect of enabling Idle HLT is that, if a virtual
interupt is pending and unmasked at the time of HLT, the vCPU will take
a V_IRQ intercept instead of a HLT intercept.

When AVIC is enabled, Idle HLT works as intended: the vCPU continues
unimpeded and services the pending virtual interrupt.

Note, the APM's description of V_IRQ interaction with AVIC is quite
confusing, and requires piecing together implied behavior.  Per the APM,
when AVIC is enabled, V_IRQ *from the VMCB* is ignored:

  When AVIC mode is enabled for a virtual processor, the V_IRQ, V_INTR_PRIO,
  V_INTR_VECTOR, and V_IGN_TPR fields in the VMCB are ignored.

Which seems to contradict the behavior of Idle HLT:

  This intercept occurs only if a virtual interrupt is not pending (V_INTR
  or V_NMI).

What's not explicitly stated is that hardware's internal copy of V_IRQ
(and related fields) *are* still active, i.e. are presumably used to cache
information from the virtual APIC.

Handle Idle HLT exits as if they were normal HLT exits, e.g. don't try to
optimize the handling under the assumption that there isn't a pending IRQ.
Irrespective of AVIC, Idle HLT is inherently racy with respect to the vIRR,
as KVM can set vIRR bits asychronously.

No changes are required to support KVM's use Idle HLT while running
L2.  In fact, supporting Idle HLT is actually a bug fix to some extent.
If L1 wants to intercept HLT, recalc_intercepts() will enable HLT
interception in vmcb02 and forward the intercept to L1 as normal.

But if L1 does not want to intercept HLT, then KVM will run L2 with Idle
HLT enabled and HLT interception disabled.  If a V_IRQ or V_NMI for L2
becomes pending and L2 executes HLT, then use of Idle HLT will do the
right thing, i.e. not #VMEXIT and instead deliver the virtual event.  KVM
currently doesn't handle this scenario correctly, e.g. doesn't check V_IRQ
or V_NMI in vmcs02 as part of kvm_vcpu_has_events().

Do not expose Idle HLT to L1 at this time, as supporting nested Idle HLT is
more complex than just enumerating the feature, e.g. requires KVM to handle
the aforementioned scenarios of V_IRQ and V_NMI at the time of exit.

Signed-off-by: Manali Shukla <Manali.Shukla@amd.com>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://bugzilla.kernel.org/attachment.cgi?id=306250
Link: https://lore.kernel.org/r/20250128124812.7324-3-manali.shukla@amd.com
[sean: rewrite changelog, drop nested "support"]
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-25 16:30:02 -08:00
Sean Christopherson
5c17848134 KVM: x86/xen: Restrict hypercall MSR to unofficial synthetic range
Reject userspace attempts to set the Xen hypercall page MSR to an index
outside of the "standard" virtualization range [0x40000000, 0x4fffffff],
as KVM is not equipped to handle collisions with real MSRs, e.g. KVM
doesn't update MSR interception, conflicts with VMCS/VMCB fields, special
case writes in KVM, etc.

While the MSR index isn't strictly ABI, i.e. can theoretically float to
any value, in practice no known VMM sets the MSR index to anything other
than 0x40000000 or 0x40000200.

Cc: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Link: https://lore.kernel.org/r/20250215011437.1203084-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2025-02-24 08:59:55 -08:00
Linus Torvalds
0f8e26b38d Loongarch:
* Clear LLBCTL if secondary mmu mapping changes.
 
 * Add hypercall service support for usermode VMM.
 
 x86:
 
 * Add a comment to kvm_mmu_do_page_fault() to explain why KVM performs a
   direct call to kvm_tdp_page_fault() when RETPOLINE is enabled.
 
 * Ensure that all SEV code is compiled out when disabled in Kconfig, even
   if building with less brilliant compilers.
 
 * Remove a redundant TLB flush on AMD processors when guest CR4.PGE changes.
 
 * Use str_enabled_disabled() to replace open coded strings.
 
 * Drop kvm_x86_ops.hwapic_irr_update() as KVM updates hardware's APICv cache
   prior to every VM-Enter.
 
 * Overhaul KVM's CPUID feature infrastructure to track all vCPU capabilities
   instead of just those where KVM needs to manage state and/or explicitly
   enable the feature in hardware.  Along the way, refactor the code to make
   it easier to add features, and to make it more self-documenting how KVM
   is handling each feature.
 
 * Rework KVM's handling of VM-Exits during event vectoring; this plugs holes
   where KVM unintentionally puts the vCPU into infinite loops in some scenarios
   (e.g. if emulation is triggered by the exit), and brings parity between VMX
   and SVM.
 
 * Add pending request and interrupt injection information to the kvm_exit and
   kvm_entry tracepoints respectively.
 
 * Fix a relatively benign flaw where KVM would end up redoing RDPKRU when
   loading guest/host PKRU, due to a refactoring of the kernel helpers that
   didn't account for KVM's pre-checking of the need to do WRPKRU.
 
 * Make the completion of hypercalls go through the complete_hypercall
   function pointer argument, no matter if the hypercall exits to
   userspace or not.  Previously, the code assumed that KVM_HC_MAP_GPA_RANGE
   specifically went to userspace, and all the others did not; the new code
   need not special case KVM_HC_MAP_GPA_RANGE and in fact does not care at
   all whether there was an exit to userspace or not.
 
 * As part of enabling TDX virtual machines, support support separation of
   private/shared EPT into separate roots.  When TDX will be enabled, operations
   on private pages will need to go through the privileged TDX Module via SEAMCALLs;
   as a result, they are limited and relatively slow compared to reading a PTE.
   The patches included in 6.14 allow KVM to keep a mirror of the private EPT in
   host memory, and define entries in kvm_x86_ops to operate on external page
   tables such as the TDX private EPT.
 
 * The recently introduced conversion of the NX-page reclamation kthread to
   vhost_task moved the task under the main process.  The task is created as
   soon as KVM_CREATE_VM was invoked and this, of course, broke userspace that
   didn't expect to see any child task of the VM process until it started
   creating its own userspace threads.  In particular crosvm refuses to fork()
   if procfs shows any child task, so unbreak it by creating the task lazily.
   This is arguably a userspace bug, as there can be other kinds of legitimate
   worker tasks and they wouldn't impede fork(); but it's not like userspace
   has a way to distinguish kernel worker tasks right now.  Should they show
   as "Kthread: 1" in proc/.../status?
 
 x86 - Intel:
 
 * Fix a bug where KVM updates hardware's APICv cache of the highest ISR bit
   while L2 is active, while ultimately results in a hardware-accelerated L1
   EOI effectively being lost.
 
 * Honor event priority when emulating Posted Interrupt delivery during nested
   VM-Enter by queueing KVM_REQ_EVENT instead of immediately handling the
   interrupt.
 
 * Rework KVM's processing of the Page-Modification Logging buffer to reap
   entries in the same order they were created, i.e. to mark gfns dirty in the
   same order that hardware marked the page/PTE dirty.
 
 * Misc cleanups.
 
 Generic:
 
 * Cleanup and harden kvm_set_memory_region(); add proper lockdep assertions when
   setting memory regions and add a dedicated API for setting KVM-internal
   memory regions.  The API can then explicitly disallow all flags for
   KVM-internal memory regions.
 
 * Explicitly verify the target vCPU is online in kvm_get_vcpu() to fix a bug
   where KVM would return a pointer to a vCPU prior to it being fully online,
   and give kvm_for_each_vcpu() similar treatment to fix a similar flaw.
 
 * Wait for a vCPU to come online prior to executing a vCPU ioctl, to fix a
   bug where userspace could coerce KVM into handling the ioctl on a vCPU that
   isn't yet onlined.
 
 * Gracefully handle xarray insertion failures; even though such failures are
   impossible in practice after xa_reserve(), reserving an entry is always followed
   by xa_store() which does not know (or differentiate) whether there was an
   xa_reserve() before or not.
 
 RISC-V:
 
 * Zabha, Svvptc, and Ziccrse extension support for guests.  None of them
   require anything in KVM except for detecting them and marking them
   as supported; Zabha adds byte and halfword atomic operations, while the
   others are markers for specific operation of the TLB and of LL/SC
   instructions respectively.
 
 * Virtualize SBI system suspend extension for Guest/VM
 
 * Support firmware counters which can be used by the guests to collect
   statistics about traps that occur in the host.
 
 Selftests:
 
 * Rework vcpu_get_reg() to return a value instead of using an out-param, and
   update all affected arch code accordingly.
 
 * Convert the max_guest_memory_test into a more generic mmu_stress_test.
   The basic gist of the "conversion" is to have the test do mprotect() on
   guest memory while vCPUs are accessing said memory, e.g. to verify KVM
   and mmu_notifiers are working as intended.
 
 * Play nice with treewrite builds of unsupported architectures, e.g. arm
   (32-bit), as KVM selftests' Makefile doesn't do anything to ensure the
   target architecture is actually one KVM selftests supports.
 
 * Use the kernel's $(ARCH) definition instead of the target triple for arch
   specific directories, e.g. arm64 instead of aarch64, mainly so as not to
   be different from the rest of the kernel.
 
 * Ensure that format strings for logging statements are checked by the
   compiler even when the logging statement itself is disabled.
 
 * Attempt to whack the last LLC references/misses mole in the Intel PMU
   counters test by adding a data load and doing CLFLUSH{OPT} on the data
   instead of the code being executed.  It seems that modern Intel CPUs
   have learned new code prefetching tricks that bypass the PMU counters.
 
 * Fix a flaw in the Intel PMU counters test where it asserts that events
   are counting correctly without actually knowing what the events count
   given the underlying hardware; this can happen if Intel reuses a
   formerly microarchitecture-specific event encoding as an architectural
   event, as was the case for Top-Down Slots.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "Loongarch:

   - Clear LLBCTL if secondary mmu mapping changes

   - Add hypercall service support for usermode VMM

  x86:

   - Add a comment to kvm_mmu_do_page_fault() to explain why KVM
     performs a direct call to kvm_tdp_page_fault() when RETPOLINE is
     enabled

   - Ensure that all SEV code is compiled out when disabled in Kconfig,
     even if building with less brilliant compilers

   - Remove a redundant TLB flush on AMD processors when guest CR4.PGE
     changes

   - Use str_enabled_disabled() to replace open coded strings

   - Drop kvm_x86_ops.hwapic_irr_update() as KVM updates hardware's
     APICv cache prior to every VM-Enter

   - Overhaul KVM's CPUID feature infrastructure to track all vCPU
     capabilities instead of just those where KVM needs to manage state
     and/or explicitly enable the feature in hardware. Along the way,
     refactor the code to make it easier to add features, and to make it
     more self-documenting how KVM is handling each feature

   - Rework KVM's handling of VM-Exits during event vectoring; this
     plugs holes where KVM unintentionally puts the vCPU into infinite
     loops in some scenarios (e.g. if emulation is triggered by the
     exit), and brings parity between VMX and SVM

   - Add pending request and interrupt injection information to the
     kvm_exit and kvm_entry tracepoints respectively

   - Fix a relatively benign flaw where KVM would end up redoing RDPKRU
     when loading guest/host PKRU, due to a refactoring of the kernel
     helpers that didn't account for KVM's pre-checking of the need to
     do WRPKRU

   - Make the completion of hypercalls go through the complete_hypercall
     function pointer argument, no matter if the hypercall exits to
     userspace or not.

     Previously, the code assumed that KVM_HC_MAP_GPA_RANGE specifically
     went to userspace, and all the others did not; the new code need
     not special case KVM_HC_MAP_GPA_RANGE and in fact does not care at
     all whether there was an exit to userspace or not

   - As part of enabling TDX virtual machines, support support
     separation of private/shared EPT into separate roots.

     When TDX will be enabled, operations on private pages will need to
     go through the privileged TDX Module via SEAMCALLs; as a result,
     they are limited and relatively slow compared to reading a PTE.

     The patches included in 6.14 allow KVM to keep a mirror of the
     private EPT in host memory, and define entries in kvm_x86_ops to
     operate on external page tables such as the TDX private EPT

   - The recently introduced conversion of the NX-page reclamation
     kthread to vhost_task moved the task under the main process. The
     task is created as soon as KVM_CREATE_VM was invoked and this, of
     course, broke userspace that didn't expect to see any child task of
     the VM process until it started creating its own userspace threads.

     In particular crosvm refuses to fork() if procfs shows any child
     task, so unbreak it by creating the task lazily. This is arguably a
     userspace bug, as there can be other kinds of legitimate worker
     tasks and they wouldn't impede fork(); but it's not like userspace
     has a way to distinguish kernel worker tasks right now. Should they
     show as "Kthread: 1" in proc/.../status?

  x86 - Intel:

   - Fix a bug where KVM updates hardware's APICv cache of the highest
     ISR bit while L2 is active, while ultimately results in a
     hardware-accelerated L1 EOI effectively being lost

   - Honor event priority when emulating Posted Interrupt delivery
     during nested VM-Enter by queueing KVM_REQ_EVENT instead of
     immediately handling the interrupt

   - Rework KVM's processing of the Page-Modification Logging buffer to
     reap entries in the same order they were created, i.e. to mark gfns
     dirty in the same order that hardware marked the page/PTE dirty

   - Misc cleanups

  Generic:

   - Cleanup and harden kvm_set_memory_region(); add proper lockdep
     assertions when setting memory regions and add a dedicated API for
     setting KVM-internal memory regions. The API can then explicitly
     disallow all flags for KVM-internal memory regions

   - Explicitly verify the target vCPU is online in kvm_get_vcpu() to
     fix a bug where KVM would return a pointer to a vCPU prior to it
     being fully online, and give kvm_for_each_vcpu() similar treatment
     to fix a similar flaw

   - Wait for a vCPU to come online prior to executing a vCPU ioctl, to
     fix a bug where userspace could coerce KVM into handling the ioctl
     on a vCPU that isn't yet onlined

   - Gracefully handle xarray insertion failures; even though such
     failures are impossible in practice after xa_reserve(), reserving
     an entry is always followed by xa_store() which does not know (or
     differentiate) whether there was an xa_reserve() before or not

  RISC-V:

   - Zabha, Svvptc, and Ziccrse extension support for guests. None of
     them require anything in KVM except for detecting them and marking
     them as supported; Zabha adds byte and halfword atomic operations,
     while the others are markers for specific operation of the TLB and
     of LL/SC instructions respectively

   - Virtualize SBI system suspend extension for Guest/VM

   - Support firmware counters which can be used by the guests to
     collect statistics about traps that occur in the host

  Selftests:

   - Rework vcpu_get_reg() to return a value instead of using an
     out-param, and update all affected arch code accordingly

   - Convert the max_guest_memory_test into a more generic
     mmu_stress_test. The basic gist of the "conversion" is to have the
     test do mprotect() on guest memory while vCPUs are accessing said
     memory, e.g. to verify KVM and mmu_notifiers are working as
     intended

   - Play nice with treewrite builds of unsupported architectures, e.g.
     arm (32-bit), as KVM selftests' Makefile doesn't do anything to
     ensure the target architecture is actually one KVM selftests
     supports

   - Use the kernel's $(ARCH) definition instead of the target triple
     for arch specific directories, e.g. arm64 instead of aarch64,
     mainly so as not to be different from the rest of the kernel

   - Ensure that format strings for logging statements are checked by
     the compiler even when the logging statement itself is disabled

   - Attempt to whack the last LLC references/misses mole in the Intel
     PMU counters test by adding a data load and doing CLFLUSH{OPT} on
     the data instead of the code being executed. It seems that modern
     Intel CPUs have learned new code prefetching tricks that bypass the
     PMU counters

   - Fix a flaw in the Intel PMU counters test where it asserts that
     events are counting correctly without actually knowing what the
     events count given the underlying hardware; this can happen if
     Intel reuses a formerly microarchitecture-specific event encoding
     as an architectural event, as was the case for Top-Down Slots"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (151 commits)
  kvm: defer huge page recovery vhost task to later
  KVM: x86/mmu: Return RET_PF* instead of 1 in kvm_mmu_page_fault()
  KVM: Disallow all flags for KVM-internal memslots
  KVM: x86: Drop double-underscores from __kvm_set_memory_region()
  KVM: Add a dedicated API for setting KVM-internal memslots
  KVM: Assert slots_lock is held when setting memory regions
  KVM: Open code kvm_set_memory_region() into its sole caller (ioctl() API)
  LoongArch: KVM: Add hypercall service support for usermode VMM
  LoongArch: KVM: Clear LLBCTL if secondary mmu mapping is changed
  KVM: SVM: Use str_enabled_disabled() helper in svm_hardware_setup()
  KVM: VMX: read the PML log in the same order as it was written
  KVM: VMX: refactor PML terminology
  KVM: VMX: Fix comment of handle_vmx_instruction()
  KVM: VMX: Reinstate __exit attribute for vmx_exit()
  KVM: SVM: Use str_enabled_disabled() helper in sev_hardware_setup()
  KVM: x86: Avoid double RDPKRU when loading host/guest PKRU
  KVM: x86: Use LVT_TIMER instead of an open coded literal
  RISC-V: KVM: Add new exit statstics for redirected traps
  RISC-V: KVM: Update firmware counters for various events
  RISC-V: KVM: Redirect instruction access fault trap to guest
  ...
2025-01-25 09:55:09 -08:00
Rick Edgecombe
9364789567 KVM: x86: Add a VM type define for TDX
Add a VM type define for TDX.

Future changes will need to lay the ground work for TDX support by
making some behavior conditional on the VM being a TDX guest.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Message-ID: <20240718211230.1492011-4-rick.p.edgecombe@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-12-23 08:28:55 -05:00
Suma Hegde
836d0d7107
platform/x86/amd/hsmp: Add support for HSMP protocol version 7 messages
Following new HSMP messages are available on family 0x1A, model 0x00-0x1F
platforms with protocol version 7. Add support for them in the driver.
- SetXgmiPstateRange(26h)
- CpuRailIsoFreqPolicy(27h)
- DfcEnable(28h)
- GetRaplUnit(30h)
- GetRaplCoreCounter(31h)
- GetRaplPackageCounter(32h)

Also update HSMP message PwrEfficiencyModeSelection-21h. This message is
updated to include GET option in recent firmware.

Signed-off-by: Suma Hegde <suma.hegde@amd.com>
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Link: https://lore.kernel.org/r/20241118102752.11703-1-suma.hegde@amd.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
2024-12-02 19:20:14 +02:00
Linus Torvalds
9f16d5e6f2 The biggest change here is eliminating the awful idea that KVM had, of
essentially guessing which pfns are refcounted pages.  The reason to
 do so was that KVM needs to map both non-refcounted pages (for example
 BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP VMAs that contain
 refcounted pages.  However, the result was security issues in the past,
 and more recently the inability to map VM_IO and VM_PFNMAP memory
 that _is_ backed by struct page but is not refcounted.  In particular
 this broke virtio-gpu blob resources (which directly map host graphics
 buffers into the guest as "vram" for the virtio-gpu device) with the
 amdgpu driver, because amdgpu allocates non-compound higher order pages
 and the tail pages could not be mapped into KVM.
 
 This requires adjusting all uses of struct page in the per-architecture
 code, to always work on the pfn whenever possible.  The large series that
 did this, from David Stevens and Sean Christopherson, also cleaned up
 substantially the set of functions that provided arch code with the
 pfn for a host virtual addresses.  The previous maze of twisty little
 passages, all different, is replaced by five functions (__gfn_to_page,
 __kvm_faultin_pfn, the non-__ versions of these two, and kvm_prefetch_pages)
 saving almost 200 lines of code.
 
 ARM:
 
 * Support for stage-1 permission indirection (FEAT_S1PIE) and
   permission overlays (FEAT_S1POE), including nested virt + the
   emulated page table walker
 
 * Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This call
   was introduced in PSCIv1.3 as a mechanism to request hibernation,
   similar to the S4 state in ACPI
 
 * Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
   part of it, introduce trivial initialization of the host's MPAM
   context so KVM can use the corresponding traps
 
 * PMU support under nested virtualization, honoring the guest
   hypervisor's trap configuration and event filtering when running a
   nested guest
 
 * Fixes to vgic ITS serialization where stale device/interrupt table
   entries are not zeroed when the mapping is invalidated by the VM
 
 * Avoid emulated MMIO completion if userspace has requested synchronous
   external abort injection
 
 * Various fixes and cleanups affecting pKVM, vCPU initialization, and
   selftests
 
 LoongArch:
 
 * Add iocsr and mmio bus simulation in kernel.
 
 * Add in-kernel interrupt controller emulation.
 
 * Add support for virtualization extensions to the eiointc irqchip.
 
 PPC:
 
 * Drop lingering and utterly obsolete references to PPC970 KVM, which was
   removed 10 years ago.
 
 * Fix incorrect documentation references to non-existing ioctls
 
 RISC-V:
 
 * Accelerate KVM RISC-V when running as a guest
 
 * Perf support to collect KVM guest statistics from host side
 
 s390:
 
 * New selftests: more ucontrol selftests and CPU model sanity checks
 
 * Support for the gen17 CPU model
 
 * List registers supported by KVM_GET/SET_ONE_REG in the documentation
 
 x86:
 
 * Cleanup KVM's handling of Accessed and Dirty bits to dedup code, improve
   documentation, harden against unexpected changes.  Even if the hardware
   A/D tracking is disabled, it is possible to use the hardware-defined A/D
   bits to track if a PFN is Accessed and/or Dirty, and that removes a lot
   of special cases.
 
 * Elide TLB flushes when aging secondary PTEs, as has been done in x86's
   primary MMU for over 10 years.
 
 * Recover huge pages in-place in the TDP MMU when dirty page logging is
   toggled off, instead of zapping them and waiting until the page is
   re-accessed to create a huge mapping.  This reduces vCPU jitter.
 
 * Batch TLB flushes when dirty page logging is toggled off.  This reduces
   the time it takes to disable dirty logging by ~3x.
 
 * Remove the shrinker that was (poorly) attempting to reclaim shadow page
   tables in low-memory situations.
 
 * Clean up and optimize KVM's handling of writes to MSR_IA32_APICBASE.
 
 * Advertise CPUIDs for new instructions in Clearwater Forest
 
 * Quirk KVM's misguided behavior of initialized certain feature MSRs to
   their maximum supported feature set, which can result in KVM creating
   invalid vCPU state.  E.g. initializing PERF_CAPABILITIES to a non-zero
   value results in the vCPU having invalid state if userspace hides PDCM
   from the guest, which in turn can lead to save/restore failures.
 
 * Fix KVM's handling of non-canonical checks for vCPUs that support LA57
   to better follow the "architecture", in quotes because the actual
   behavior is poorly documented.  E.g. most MSR writes and descriptor
   table loads ignore CR4.LA57 and operate purely on whether the CPU
   supports LA57.
 
 * Bypass the register cache when querying CPL from kvm_sched_out(), as
   filling the cache from IRQ context is generally unsafe; harden the
   cache accessors to try to prevent similar issues from occuring in the
   future.  The issue that triggered this change was already fixed in 6.12,
   but was still kinda latent.
 
 * Advertise AMD_IBPB_RET to userspace, and fix a related bug where KVM
   over-advertises SPEC_CTRL when trying to support cross-vendor VMs.
 
 * Minor cleanups
 
 * Switch hugepage recovery thread to use vhost_task.  These kthreads can
   consume significant amounts of CPU time on behalf of a VM or in response
   to how the VM behaves (for example how it accesses its memory); therefore
   KVM tried to place the thread in the VM's cgroups and charge the CPU
   time consumed by that work to the VM's container.  However the kthreads
   did not process SIGSTOP/SIGCONT, and therefore cgroups which had KVM
   instances inside could not complete freezing.  Fix this by replacing the
   kthread with a PF_USER_WORKER thread, via the vhost_task abstraction.
   Another 100+ lines removed, with generally better behavior too like
   having these threads properly parented in the process tree.
 
 * Revert a workaround for an old CPU erratum (Nehalem/Westmere) that didn't
   really work; there was really nothing to work around anyway: the broken
   patch was meant to fix nested virtualization, but the PERF_GLOBAL_CTRL
   MSR is virtualized and therefore unaffected by the erratum.
 
 * Fix 6.12 regression where CONFIG_KVM will be built as a module even
   if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is 'y'.
 
 x86 selftests:
 
 * x86 selftests can now use AVX.
 
 Documentation:
 
 * Use rST internal links
 
 * Reorganize the introduction to the API document
 
 Generic:
 
 * Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock instead
   of RCU, so that running a vCPU on a different task doesn't encounter long
   due to having to wait for all CPUs become quiescent.  In general both reads
   and writes are rare, but userspace that supports confidential computing is
   introducing the use of "helper" vCPUs that may jump from one host processor
   to another.  Those will be very happy to trigger a synchronize_rcu(), and
   the effect on performance is quite the disaster.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "The biggest change here is eliminating the awful idea that KVM had of
  essentially guessing which pfns are refcounted pages.

  The reason to do so was that KVM needs to map both non-refcounted
  pages (for example BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP
  VMAs that contain refcounted pages.

  However, the result was security issues in the past, and more recently
  the inability to map VM_IO and VM_PFNMAP memory that _is_ backed by
  struct page but is not refcounted. In particular this broke virtio-gpu
  blob resources (which directly map host graphics buffers into the
  guest as "vram" for the virtio-gpu device) with the amdgpu driver,
  because amdgpu allocates non-compound higher order pages and the tail
  pages could not be mapped into KVM.

  This requires adjusting all uses of struct page in the
  per-architecture code, to always work on the pfn whenever possible.
  The large series that did this, from David Stevens and Sean
  Christopherson, also cleaned up substantially the set of functions
  that provided arch code with the pfn for a host virtual addresses.

  The previous maze of twisty little passages, all different, is
  replaced by five functions (__gfn_to_page, __kvm_faultin_pfn, the
  non-__ versions of these two, and kvm_prefetch_pages) saving almost
  200 lines of code.

  ARM:

   - Support for stage-1 permission indirection (FEAT_S1PIE) and
     permission overlays (FEAT_S1POE), including nested virt + the
     emulated page table walker

   - Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This
     call was introduced in PSCIv1.3 as a mechanism to request
     hibernation, similar to the S4 state in ACPI

   - Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
     part of it, introduce trivial initialization of the host's MPAM
     context so KVM can use the corresponding traps

   - PMU support under nested virtualization, honoring the guest
     hypervisor's trap configuration and event filtering when running a
     nested guest

   - Fixes to vgic ITS serialization where stale device/interrupt table
     entries are not zeroed when the mapping is invalidated by the VM

   - Avoid emulated MMIO completion if userspace has requested
     synchronous external abort injection

   - Various fixes and cleanups affecting pKVM, vCPU initialization, and
     selftests

  LoongArch:

   - Add iocsr and mmio bus simulation in kernel.

   - Add in-kernel interrupt controller emulation.

   - Add support for virtualization extensions to the eiointc irqchip.

  PPC:

   - Drop lingering and utterly obsolete references to PPC970 KVM, which
     was removed 10 years ago.

   - Fix incorrect documentation references to non-existing ioctls

  RISC-V:

   - Accelerate KVM RISC-V when running as a guest

   - Perf support to collect KVM guest statistics from host side

  s390:

   - New selftests: more ucontrol selftests and CPU model sanity checks

   - Support for the gen17 CPU model

   - List registers supported by KVM_GET/SET_ONE_REG in the
     documentation

  x86:

   - Cleanup KVM's handling of Accessed and Dirty bits to dedup code,
     improve documentation, harden against unexpected changes.

     Even if the hardware A/D tracking is disabled, it is possible to
     use the hardware-defined A/D bits to track if a PFN is Accessed
     and/or Dirty, and that removes a lot of special cases.

   - Elide TLB flushes when aging secondary PTEs, as has been done in
     x86's primary MMU for over 10 years.

   - Recover huge pages in-place in the TDP MMU when dirty page logging
     is toggled off, instead of zapping them and waiting until the page
     is re-accessed to create a huge mapping. This reduces vCPU jitter.

   - Batch TLB flushes when dirty page logging is toggled off. This
     reduces the time it takes to disable dirty logging by ~3x.

   - Remove the shrinker that was (poorly) attempting to reclaim shadow
     page tables in low-memory situations.

   - Clean up and optimize KVM's handling of writes to
     MSR_IA32_APICBASE.

   - Advertise CPUIDs for new instructions in Clearwater Forest

   - Quirk KVM's misguided behavior of initialized certain feature MSRs
     to their maximum supported feature set, which can result in KVM
     creating invalid vCPU state. E.g. initializing PERF_CAPABILITIES to
     a non-zero value results in the vCPU having invalid state if
     userspace hides PDCM from the guest, which in turn can lead to
     save/restore failures.

   - Fix KVM's handling of non-canonical checks for vCPUs that support
     LA57 to better follow the "architecture", in quotes because the
     actual behavior is poorly documented. E.g. most MSR writes and
     descriptor table loads ignore CR4.LA57 and operate purely on
     whether the CPU supports LA57.

   - Bypass the register cache when querying CPL from kvm_sched_out(),
     as filling the cache from IRQ context is generally unsafe; harden
     the cache accessors to try to prevent similar issues from occuring
     in the future. The issue that triggered this change was already
     fixed in 6.12, but was still kinda latent.

   - Advertise AMD_IBPB_RET to userspace, and fix a related bug where
     KVM over-advertises SPEC_CTRL when trying to support cross-vendor
     VMs.

   - Minor cleanups

   - Switch hugepage recovery thread to use vhost_task.

     These kthreads can consume significant amounts of CPU time on
     behalf of a VM or in response to how the VM behaves (for example
     how it accesses its memory); therefore KVM tried to place the
     thread in the VM's cgroups and charge the CPU time consumed by that
     work to the VM's container.

     However the kthreads did not process SIGSTOP/SIGCONT, and therefore
     cgroups which had KVM instances inside could not complete freezing.

     Fix this by replacing the kthread with a PF_USER_WORKER thread, via
     the vhost_task abstraction. Another 100+ lines removed, with
     generally better behavior too like having these threads properly
     parented in the process tree.

   - Revert a workaround for an old CPU erratum (Nehalem/Westmere) that
     didn't really work; there was really nothing to work around anyway:
     the broken patch was meant to fix nested virtualization, but the
     PERF_GLOBAL_CTRL MSR is virtualized and therefore unaffected by the
     erratum.

   - Fix 6.12 regression where CONFIG_KVM will be built as a module even
     if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is
     'y'.

  x86 selftests:

   - x86 selftests can now use AVX.

  Documentation:

   - Use rST internal links

   - Reorganize the introduction to the API document

  Generic:

   - Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock
     instead of RCU, so that running a vCPU on a different task doesn't
     encounter long due to having to wait for all CPUs become quiescent.

     In general both reads and writes are rare, but userspace that
     supports confidential computing is introducing the use of "helper"
     vCPUs that may jump from one host processor to another. Those will
     be very happy to trigger a synchronize_rcu(), and the effect on
     performance is quite the disaster"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (298 commits)
  KVM: x86: Break CONFIG_KVM_X86's direct dependency on KVM_INTEL || KVM_AMD
  KVM: x86: add back X86_LOCAL_APIC dependency
  Revert "KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config()"
  KVM: x86: switch hugepage recovery thread to vhost_task
  KVM: x86: expose MSR_PLATFORM_INFO as a feature MSR
  x86: KVM: Advertise CPUIDs for new instructions in Clearwater Forest
  Documentation: KVM: fix malformed table
  irqchip/loongson-eiointc: Add virt extension support
  LoongArch: KVM: Add irqfd support
  LoongArch: KVM: Add PCHPIC user mode read and write functions
  LoongArch: KVM: Add PCHPIC read and write functions
  LoongArch: KVM: Add PCHPIC device support
  LoongArch: KVM: Add EIOINTC user mode read and write functions
  LoongArch: KVM: Add EIOINTC read and write functions
  LoongArch: KVM: Add EIOINTC device support
  LoongArch: KVM: Add IPI user mode read and write function
  LoongArch: KVM: Add IPI read and write function
  LoongArch: KVM: Add IPI device support
  LoongArch: KVM: Add iocsr and mmio bus simulation in kernel
  KVM: arm64: Pass on SVE mapping failures
  ...
2024-11-23 16:00:50 -08:00
Linus Torvalds
fcb3ad4366 platform-drivers-x86 for v6.13-1
Highlights:
  - alienware-wmi:	WMAX thermal interface support
  - amd/hsmp:		Split ACPI and platform device based drivers
  - amd/x3d_vcache:	X3D frequency/cache mode switching support
  - asus-wmi:		Thermal policy fixes
  - intel/pmt:		Disable C1 auto-demotion in suspend to allow
 			entering the deepest C-states
  - intel-hid:		Fix volume buttons on Thinkpad X12 Detachable
 			Tablet Gen 1
  - intel_scu_ipc:	Replace "workaround" with 32-bit IO
  - panasonic-laptop:	Correct *_show() function error handling
  - p2sb:		Gemini Lake P2SB devfn correction
  - think-lmi:		Admin/System certificate authentication support
  - wmi:			Disable WMI devices for shutdown, refactoring
 			continues
  - x86-android-tablets:	Vexia EDU ATLA 10 tablet support
  - platform/surface:	Surface Pro 9 5G (Arm/QCOM) support
  - Miscellaneous cleanups / refactoring / improvements
 
 Expected conflicts:
  - hsmp driver split into two vs constifying bin_attribute [1]
 
 [1] https://lore.kernel.org/all/20241107212645.41252436@canb.auug.org.au/
 
 The following is an automated shortlog grouped by driver:
 
 alienware-wmi:
  -  added force module parameters
  -  added platform profile support
  -  Adds support to Alienware x17 R2
  -  alienware_wmax_command() is now input size agnostic
  -  create_thermal_profile() no longer brute-forces IDs
  -  extends the list of supported models
  -  fixed indentation and clean up
  -  Fix spelling mistake "requieres" -> "requires"
  -  order alienware_quirks[] alphabetically
  -  WMAX interface documentation
 
 amd: amd_3d_vcache:
  -  Add AMD 3D V-Cache optimizer driver
  -  Add sysfs ABI documentation
 
 amd/hsmp:
  -  Add new error code and error logs
  -  Change generic plat_dev name to hsmp_pdev
  -  Change the error type
  -  Convert amd_hsmp_rdwr() to a function pointer
  -  Create hsmp/ directory
  -  Create separate ACPI, plat and common drivers
  -  Create wrapper function init_acpi()
  -  Make hsmp_pdev static instead of global
  -  mark hsmp_msg_desc_table[] as maybe_unused
  -  Move ACPI code to acpi.c
  -  Move platform device specific code to plat.c
  -  Move structure and macros to header file
  -  Use dev_groups in the driver structure
  -  Use name space while exporting module symbols
 
 amd/pmf:
  -  Switch to platform_get_resource() and devm_ioremap_resource()
  -  Use dev_err_probe() to simplify error handling
 
 asus-laptop:
  -  prefer strscpy() over strcpy()
 
 asus-wmi:
  -  Fix inconsistent use of thermal policies
  -  Use platform_profile_cycle()
 
 classmate-laptop:
  -  Replace snprintf in show functions with sysfs_emit
 
 compal-laptop:
  -  use sysfs_emit() instead of sprintf()
 
 dell-dcdbase:
  -  Replace snprintf in show functions with sysfs_emit
 
 Documentation: alienware-wmi:
  -  Describe THERMAL_INFORMATION operation 0x02
 
 eeepc-laptop:
  -  use sysfs_emit() instead of sprintf()
 
 hp: hp-bioscfg:
  -  remove redundant if statement
 
 intel:
  -  Add 'intel' prefix to the modules automatically
 
 intel-hid:
  -  fix volume buttons on Thinkpad X12 Detachable Tablet Gen 1
 
 intel/pmc:
  -  Disable C1 auto-demotion during suspend
  -  Refactor platform resume functions to use cnl_resume()
 
 intel/pmt:
  -  allow user offset for PMT callbacks
  -  Correct the typo 'ACCCESS_LOCAL'
 
 intel_scu_ipc:
  -  Convert to check for errors first
  -  Don't use "proxy" headers
  -  Replace workaround by 32-bit IO
  -  Save a copy of the entire struct intel_scu_ipc_data
  -  Simplify code with cleanup helpers
  -  Unify the flow in pwr_reg_rdwr()
 
 intel/vsec:
  -  Remove a useless mutex
 
 MAINTAINERS:
  -  adjust file entry in INTEL TPMI DRIVER
  -  Change AMD PMF driver status to "Supported"
  -  Update ISHTP ECLITE maintainer entry
 
 p2sb:
  -  Cache correct PCI bar for P2SB on Gemini Lake
 
 panasonic-laptop:
  -  Return errno correctly in show callback
 
 surface: aggregator_registry:
  -  Add Surface Pro 9 5G
 
 Switch back to struct platform_driver::
  - remove()
 
 think-lmi:
  -  Add certificate as mechanism
  -  Allow empty admin password
  -  improve check if BIOS account security enabled
  -  Multi-certificate support
 
 wmi:
  -  Implement proper shutdown handling
  -  Introduce to_wmi_driver()
  -  Remove wmi_block_list
  -  Replace dev_to_wdev() with to_wmi_device()
 
 x86: acer-wmi:
  -  remove unused macros
 
 x86-android-tablets:
  -  Add get_i2c_adap_by_handle() helper
  -  Add support for getting i2c_adapter by PCI parent devname()
  -  Add support for Vexia EDU ATLA 10 tablet
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Merge tag 'platform-drivers-x86-v6.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86

Pull x86 platform driver updates from Ilpo Järvinen:

 - alienware WMAX thermal interface support

 - Split ACPI and platform device based amd/hsmp drivers

 - AMD X3D frequency/cache mode switching support

 - asus thermal policy fixes

 - Disable C1 auto-demotion in suspend to allow entering the deepest
   C-states

 - Fix volume buttons on Thinkpad X12 Detachable Tablet Gen 1

 - Replace intel_scu_ipc "workaround" with 32-bit IO

 - Correct *_show() function error handling in panasonic-laptop

 - Gemini Lake P2SB devfn correction

 - think-lmi Admin/System certificate authentication support

 - Disable WMI devices for shutdown, refactoring continues

 - Vexia EDU ATLA 10 tablet support

 - Surface Pro 9 5G (Arm/QCOM) support

 - Misc cleanups / refactoring / improvements

* tag 'platform-drivers-x86-v6.13-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86: (69 commits)
  platform/x86: p2sb: Cache correct PCI bar for P2SB on Gemini Lake
  platform/x86: panasonic-laptop: Return errno correctly in show callback
  Documentation: alienware-wmi: Describe THERMAL_INFORMATION operation 0x02
  alienware-wmi: create_thermal_profile() no longer brute-forces IDs
  alienware-wmi: Adds support to Alienware x17 R2
  alienware-wmi: extends the list of supported models
  alienware-wmi: order alienware_quirks[] alphabetically
  platform/x86/intel/pmt: allow user offset for PMT callbacks
  platform/x86/amd/hsmp: Change the error type
  platform/x86/amd/hsmp: Add new error code and error logs
  platform/x86/amd: amd_3d_vcache: Add sysfs ABI documentation
  platform/x86/amd: amd_3d_vcache: Add AMD 3D V-Cache optimizer driver
  intel-hid: fix volume buttons on Thinkpad X12 Detachable Tablet Gen 1
  platform/x86/amd/hsmp: mark hsmp_msg_desc_table[] as maybe_unused
  platform/x86: asus-wmi: Use platform_profile_cycle()
  platform/x86: asus-wmi: Fix inconsistent use of thermal policies
  platform/x86: hp: hp-bioscfg: remove redundant if statement
  MAINTAINERS: Update ISHTP ECLITE maintainer entry
  platform/x86: x86-android-tablets: Add support for Vexia EDU ATLA 10 tablet
  platform/x86: x86-android-tablets: Add support for getting i2c_adapter by PCI parent devname()
  ...
2024-11-20 14:07:55 -08:00
Linus Torvalds
c1f2ffe207 - Log and handle twp new AMD-specific MCA registers: SYND1 and SYND2 and
report the Field Replaceable Unit text info reported through them
 
 - Add support for handling variable-sized SMCA BERT records
 
 - Add the capability for reporting vendor-specific RAS error info without
   adding vendor-specific fields to struct mce
 
 - Cleanups
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Merge tag 'ras_core_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RAS updates from Borislav Petkov:

 - Log and handle twp new AMD-specific MCA registers: SYND1 and SYND2
   and report the Field Replaceable Unit text info reported through them

 - Add support for handling variable-sized SMCA BERT records

 - Add the capability for reporting vendor-specific RAS error info
   without adding vendor-specific fields to struct mce

 - Cleanups

* tag 'ras_core_for_v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  EDAC/mce_amd: Add support for FRU text in MCA
  x86/mce/apei: Handle variable SMCA BERT record size
  x86/MCE/AMD: Add support for new MCA_SYND{1,2} registers
  tracing: Add __print_dynamic_array() helper
  x86/mce: Add wrapper for struct mce to export vendor specific info
  x86/mce/intel: Use MCG_BANKCNT_MASK instead of 0xff
  x86/mce/mcelog: Use xchg() to get and clear the flags
2024-11-19 12:04:51 -08:00
Arnd Bergmann
0d5e2d9b8f
platform/x86/amd/hsmp: mark hsmp_msg_desc_table[] as maybe_unused
After the file got split, there are now W=1 warnings for users that
include it without referencing hsmp_msg_desc_table:

In file included from arch/x86/include/asm/amd_hsmp.h:6,
                 from drivers/platform/x86/amd/hsmp/plat.c:12:
arch/x86/include/uapi/asm/amd_hsmp.h:91:35: error: 'hsmp_msg_desc_table' defined but not used [-Werror=unused-const-variable=]
   91 | static const struct hsmp_msg_desc hsmp_msg_desc_table[] = {
      |                                   ^~~~~~~~~~~~~~~~~~~

Mark it as __attribute__((maybe_unused)) to shut up the warning but
keep it in the file in case it is used from userland. The __maybe_unused
shorthand unfortunately isn't available in userspace, so this has to
be the long form.

While it is not envisioned a normal userspace program could benefit
from having this table as part of UAPI, it seems there is non-zero
chance this array is used by some userspace tests so it is retained for
now (see the Link below).

Fixes: e47c018a0e ("platform/x86/amd/hsmp: Move platform device specific code to plat.c")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/platform-driver-x86/CAPhsuW7mDRswhVjYf+4iinO+sph_rQ1JykEof+apoiSOVwOXXQ@mail.gmail.com/
Link: https://lore.kernel.org/r/20241028163553.2452486-1-arnd@kernel.org
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
2024-11-12 12:15:36 +02:00
Sean Christopherson
dcb988cdac KVM: x86: Quirk initialization of feature MSRs to KVM's max configuration
Add a quirk to control KVM's misguided initialization of select feature
MSRs to KVM's max configuration, as enabling features by default violates
KVM's approach of letting userspace own the vCPU model, and is actively
problematic for MSRs that are conditionally supported, as the vCPU will
end up with an MSR value that userspace can't restore.  E.g. if the vCPU
is configured with PDCM=0, userspace will save and attempt to restore a
non-zero PERF_CAPABILITIES, thanks to KVM's meddling.

Link: https://lore.kernel.org/r/20240802185511.305849-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-11-01 09:22:31 -07:00
Avadhut Naik
d4fca1358e x86/MCE/AMD: Add support for new MCA_SYND{1,2} registers
Starting with Zen4, AMD's Scalable MCA systems incorporate two new registers:
MCA_SYND1 and MCA_SYND2.

These registers will include supplemental error information in addition to the
existing MCA_SYND register. The data within these registers is considered
valid if MCA_STATUS[SyndV] is set.

Userspace error decoding tools like rasdaemon gather related hardware error
information through the tracepoints.

Therefore, export these two registers through the mce_record tracepoint so
that tools like rasdaemon can parse them and output the supplemental error
information like FRU text contained in them.

  [ bp: Massage. ]

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Link: https://lore.kernel.org/r/20241022194158.110073-4-avadhut.naik@amd.com
2024-10-31 10:36:07 +01:00
Mark Brown
3630e82ab6 mman: Add map_shadow_stack() flags
In preparation for adding arm64 GCS support make the map_shadow_stack()
SHADOW_STACK_SET_TOKEN flag generic and add _SET_MARKER. The existing
flag indicates that a token usable for stack switch should be added to
the top of the newly mapped GCS region while the new flag indicates that
a top of stack marker suitable for use by unwinders should be added
above that.

For arm64 the top of stack marker is all bits 0.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Yury Khrustalev <yury.khrustalev@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20241001-arm64-gcs-v13-5-222b78d87eee@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-10-04 12:04:33 +01:00
Linus Torvalds
3efc57369a x86:
* KVM currently invalidates the entirety of the page tables, not just
   those for the memslot being touched, when a memslot is moved or deleted.
   The former does not have particularly noticeable overhead, but Intel's
   TDX will require the guest to re-accept private pages if they are
   dropped from the secure EPT, which is a non starter.  Actually,
   the only reason why this is not already being done is a bug which
   was never fully investigated and caused VM instability with assigned
   GeForce GPUs, so allow userspace to opt into the new behavior.
 
 * Advertise AVX10.1 to userspace (effectively prep work for the "real" AVX10
   functionality that is on the horizon).
 
 * Rework common MSR handling code to suppress errors on userspace accesses to
   unsupported-but-advertised MSRs.  This will allow removing (almost?) all of
   KVM's exemptions for userspace access to MSRs that shouldn't exist based on
   the vCPU model (the actual cleanup is non-trivial future work).
 
 * Rework KVM's handling of x2APIC ICR, again, because AMD (x2AVIC) splits the
   64-bit value into the legacy ICR and ICR2 storage, whereas Intel (APICv)
   stores the entire 64-bit value at the ICR offset.
 
 * Fix a bug where KVM would fail to exit to userspace if one was triggered by
   a fastpath exit handler.
 
 * Add fastpath handling of HLT VM-Exit to expedite re-entering the guest when
   there's already a pending wake event at the time of the exit.
 
 * Fix a WARN caused by RSM entering a nested guest from SMM with invalid guest
   state, by forcing the vCPU out of guest mode prior to signalling SHUTDOWN
   (the SHUTDOWN hits the VM altogether, not the nested guest)
 
 * Overhaul the "unprotect and retry" logic to more precisely identify cases
   where retrying is actually helpful, and to harden all retry paths against
   putting the guest into an infinite retry loop.
 
 * Add support for yielding, e.g. to honor NEED_RESCHED, when zapping rmaps in
   the shadow MMU.
 
 * Refactor pieces of the shadow MMU related to aging SPTEs in prepartion for
   adding multi generation LRU support in KVM.
 
 * Don't stuff the RSB after VM-Exit when RETPOLINE=y and AutoIBRS is enabled,
   i.e. when the CPU has already flushed the RSB.
 
 * Trace the per-CPU host save area as a VMCB pointer to improve readability
   and cleanup the retrieval of the SEV-ES host save area.
 
 * Remove unnecessary accounting of temporary nested VMCB related allocations.
 
 * Set FINAL/PAGE in the page fault error code for EPT violations if and only
   if the GVA is valid.  If the GVA is NOT valid, there is no guest-side page
   table walk and so stuffing paging related metadata is nonsensical.
 
 * Fix a bug where KVM would incorrectly synthesize a nested VM-Exit instead of
   emulating posted interrupt delivery to L2.
 
 * Add a lockdep assertion to detect unsafe accesses of vmcs12 structures.
 
 * Harden eVMCS loading against an impossible NULL pointer deref (really truly
   should be impossible).
 
 * Minor SGX fix and a cleanup.
 
 * Misc cleanups
 
 Generic:
 
 * Register KVM's cpuhp and syscore callbacks when enabling virtualization in
   hardware, as the sole purpose of said callbacks is to disable and re-enable
   virtualization as needed.
 
 * Enable virtualization when KVM is loaded, not right before the first VM
   is created.  Together with the previous change, this simplifies a
   lot the logic of the callbacks, because their very existence implies
   virtualization is enabled.
 
 * Fix a bug that results in KVM prematurely exiting to userspace for coalesced
   MMIO/PIO in many cases, clean up the related code, and add a testcase.
 
 * Fix a bug in kvm_clear_guest() where it would trigger a buffer overflow _if_
   the gpa+len crosses a page boundary, which thankfully is guaranteed to not
   happen in the current code base.  Add WARNs in more helpers that read/write
   guest memory to detect similar bugs.
 
 Selftests:
 
 * Fix a goof that caused some Hyper-V tests to be skipped when run on bare
   metal, i.e. NOT in a VM.
 
 * Add a regression test for KVM's handling of SHUTDOWN for an SEV-ES guest.
 
 * Explicitly include one-off assets in .gitignore.  Past Sean was completely
   wrong about not being able to detect missing .gitignore entries.
 
 * Verify userspace single-stepping works when KVM happens to handle a VM-Exit
   in its fastpath.
 
 * Misc cleanups
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull x86 kvm updates from Paolo Bonzini:
 "x86:

   - KVM currently invalidates the entirety of the page tables, not just
     those for the memslot being touched, when a memslot is moved or
     deleted.

     This does not traditionally have particularly noticeable overhead,
     but Intel's TDX will require the guest to re-accept private pages
     if they are dropped from the secure EPT, which is a non starter.

     Actually, the only reason why this is not already being done is a
     bug which was never fully investigated and caused VM instability
     with assigned GeForce GPUs, so allow userspace to opt into the new
     behavior.

   - Advertise AVX10.1 to userspace (effectively prep work for the
     "real" AVX10 functionality that is on the horizon)

   - Rework common MSR handling code to suppress errors on userspace
     accesses to unsupported-but-advertised MSRs

     This will allow removing (almost?) all of KVM's exemptions for
     userspace access to MSRs that shouldn't exist based on the vCPU
     model (the actual cleanup is non-trivial future work)

   - Rework KVM's handling of x2APIC ICR, again, because AMD (x2AVIC)
     splits the 64-bit value into the legacy ICR and ICR2 storage,
     whereas Intel (APICv) stores the entire 64-bit value at the ICR
     offset

   - Fix a bug where KVM would fail to exit to userspace if one was
     triggered by a fastpath exit handler

   - Add fastpath handling of HLT VM-Exit to expedite re-entering the
     guest when there's already a pending wake event at the time of the
     exit

   - Fix a WARN caused by RSM entering a nested guest from SMM with
     invalid guest state, by forcing the vCPU out of guest mode prior to
     signalling SHUTDOWN (the SHUTDOWN hits the VM altogether, not the
     nested guest)

   - Overhaul the "unprotect and retry" logic to more precisely identify
     cases where retrying is actually helpful, and to harden all retry
     paths against putting the guest into an infinite retry loop

   - Add support for yielding, e.g. to honor NEED_RESCHED, when zapping
     rmaps in the shadow MMU

   - Refactor pieces of the shadow MMU related to aging SPTEs in
     prepartion for adding multi generation LRU support in KVM

   - Don't stuff the RSB after VM-Exit when RETPOLINE=y and AutoIBRS is
     enabled, i.e. when the CPU has already flushed the RSB

   - Trace the per-CPU host save area as a VMCB pointer to improve
     readability and cleanup the retrieval of the SEV-ES host save area

   - Remove unnecessary accounting of temporary nested VMCB related
     allocations

   - Set FINAL/PAGE in the page fault error code for EPT violations if
     and only if the GVA is valid. If the GVA is NOT valid, there is no
     guest-side page table walk and so stuffing paging related metadata
     is nonsensical

   - Fix a bug where KVM would incorrectly synthesize a nested VM-Exit
     instead of emulating posted interrupt delivery to L2

   - Add a lockdep assertion to detect unsafe accesses of vmcs12
     structures

   - Harden eVMCS loading against an impossible NULL pointer deref
     (really truly should be impossible)

   - Minor SGX fix and a cleanup

   - Misc cleanups

  Generic:

   - Register KVM's cpuhp and syscore callbacks when enabling
     virtualization in hardware, as the sole purpose of said callbacks
     is to disable and re-enable virtualization as needed

   - Enable virtualization when KVM is loaded, not right before the
     first VM is created

     Together with the previous change, this simplifies a lot the logic
     of the callbacks, because their very existence implies
     virtualization is enabled

   - Fix a bug that results in KVM prematurely exiting to userspace for
     coalesced MMIO/PIO in many cases, clean up the related code, and
     add a testcase

   - Fix a bug in kvm_clear_guest() where it would trigger a buffer
     overflow _if_ the gpa+len crosses a page boundary, which thankfully
     is guaranteed to not happen in the current code base. Add WARNs in
     more helpers that read/write guest memory to detect similar bugs

  Selftests:

   - Fix a goof that caused some Hyper-V tests to be skipped when run on
     bare metal, i.e. NOT in a VM

   - Add a regression test for KVM's handling of SHUTDOWN for an SEV-ES
     guest

   - Explicitly include one-off assets in .gitignore. Past Sean was
     completely wrong about not being able to detect missing .gitignore
     entries

   - Verify userspace single-stepping works when KVM happens to handle a
     VM-Exit in its fastpath

   - Misc cleanups"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (127 commits)
  Documentation: KVM: fix warning in "make htmldocs"
  s390: Enable KVM_S390_UCONTROL config in debug_defconfig
  selftests: kvm: s390: Add VM run test case
  KVM: SVM: let alternatives handle the cases when RSB filling is required
  KVM: VMX: Set PFERR_GUEST_{FINAL,PAGE}_MASK if and only if the GVA is valid
  KVM: x86/mmu: Use KVM_PAGES_PER_HPAGE() instead of an open coded equivalent
  KVM: x86/mmu: Add KVM_RMAP_MANY to replace open coded '1' and '1ul' literals
  KVM: x86/mmu: Fold mmu_spte_age() into kvm_rmap_age_gfn_range()
  KVM: x86/mmu: Morph kvm_handle_gfn_range() into an aging specific helper
  KVM: x86/mmu: Honor NEED_RESCHED when zapping rmaps and blocking is allowed
  KVM: x86/mmu: Add a helper to walk and zap rmaps for a memslot
  KVM: x86/mmu: Plumb a @can_yield parameter into __walk_slot_rmaps()
  KVM: x86/mmu: Move walk_slot_rmaps() up near for_each_slot_rmap_range()
  KVM: x86/mmu: WARN on MMIO cache hit when emulating write-protected gfn
  KVM: x86/mmu: Detect if unprotect will do anything based on invalid_list
  KVM: x86/mmu: Subsume kvm_mmu_unprotect_page() into the and_retry() version
  KVM: x86: Rename reexecute_instruction()=>kvm_unprotect_and_retry_on_failure()
  KVM: x86: Update retry protection fields when forcing retry on emulation failure
  KVM: x86: Apply retry protection to "unprotect on failure" path
  KVM: x86: Check EMULTYPE_WRITE_PF_TO_SP before unprotecting gfn
  ...
2024-09-28 09:20:14 -07:00
Yan Zhao
aa8d1f48d3 KVM: x86/mmu: Introduce a quirk to control memslot zap behavior
Introduce the quirk KVM_X86_QUIRK_SLOT_ZAP_ALL to allow users to select
KVM's behavior when a memslot is moved or deleted for KVM_X86_DEFAULT_VM
VMs. Make sure KVM behave as if the quirk is always disabled for
non-KVM_X86_DEFAULT_VM VMs.

The KVM_X86_QUIRK_SLOT_ZAP_ALL quirk offers two behavior options:
- when enabled:  Invalidate/zap all SPTEs ("zap-all"),
- when disabled: Precisely zap only the leaf SPTEs within the range of the
                 moving/deleting memory slot ("zap-slot-leafs-only").

"zap-all" is today's KVM behavior to work around a bug [1] where the
changing the zapping behavior of memslot move/deletion would cause VM
instability for VMs with an Nvidia GPU assigned; while
"zap-slot-leafs-only" allows for more precise zapping of SPTEs within the
memory slot range, improving performance in certain scenarios [2], and
meeting the functional requirements for TDX.

Previous attempts to select "zap-slot-leafs-only" include a per-VM
capability approach [3] (which was not preferred because the root cause of
the bug remained unidentified) and a per-memslot flag approach [4]. Sean
and Paolo finally recommended the implementation of this quirk and
explained that it's the least bad option [5].

By default, the quirk is enabled on KVM_X86_DEFAULT_VM VMs to use
"zap-all". Users have the option to disable the quirk to select
"zap-slot-leafs-only" for specific KVM_X86_DEFAULT_VM VMs that are
unaffected by this bug.

For non-KVM_X86_DEFAULT_VM VMs, the "zap-slot-leafs-only" behavior is
always selected without user's opt-in, regardless of if the user opts for
"zap-all".
This is because it is assumed until proven otherwise that non-
KVM_X86_DEFAULT_VM VMs will not be exposed to the bug [1], and most
importantly, it's because TDX must have "zap-slot-leafs-only" always
selected. In TDX's case a memslot's GPA range can be a mixture of "private"
or "shared" memory. Shared is roughly analogous to how EPT is handled for
normal VMs, but private GPAs need lots of special treatment:
1) "zap-all" would require to zap private root page or non-leaf entries or
   at least leaf-entries beyond the deleting memslot scope. However, TDX
   demands that the root page of the private page table remains unchanged,
   with leaf entries being zapped before non-leaf entries, and any dropped
   private guest pages must be re-accepted by the guest.
2) if "zap-all" zaps only shared page tables, it would result in private
   pages still being mapped when the memslot is gone. This may affect even
   other processes if later the gmem fd was whole punched, causing the
   pages being freed on the host while still mapped in the TD, because
   there's no pgoff to the gfn information to zap the private page table
   after memslot is gone.

So, simply go "zap-slot-leafs-only" as if the quirk is always disabled for
non-KVM_X86_DEFAULT_VM VMs to avoid manual opt-in for every VM type [6] or
complicating quirk disabling interface (current quirk disabling interface
is limited, no way to query quirks, or force them to be disabled).

Add a new function kvm_mmu_zap_memslot_leafs() to implement
"zap-slot-leafs-only". This function does not call kvm_unmap_gfn_range(),
bypassing special handling to APIC_ACCESS_PAGE_PRIVATE_MEMSLOT, as
1) The APIC_ACCESS_PAGE_PRIVATE_MEMSLOT cannot be created by users, nor can
   it be moved. It is only deleted by KVM when APICv is permanently
   inhibited.
2) kvm_vcpu_reload_apic_access_page() effectively does nothing when
   APIC_ACCESS_PAGE_PRIVATE_MEMSLOT is deleted.
3) Avoid making all cpus request of KVM_REQ_APIC_PAGE_RELOAD can save on
   costly IPIs.

Suggested-by: Kai Huang <kai.huang@intel.com>
Suggested-by: Sean Christopherson <seanjc@google.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://patchwork.kernel.org/project/kvm/patch/20190205210137.1377-11-sean.j.christopherson@intel.com [1]
Link: https://patchwork.kernel.org/project/kvm/patch/20190205210137.1377-11-sean.j.christopherson@intel.com/#25054908 [2]
Link: https://lore.kernel.org/kvm/20200713190649.GE29725@linux.intel.com/T/#mabc0119583dacf621025e9d873c85f4fbaa66d5c [3]
Link: https://lore.kernel.org/all/20240515005952.3410568-3-rick.p.edgecombe@intel.com [4]
Link: https://lore.kernel.org/all/7df9032d-83e4-46a1-ab29-6c7973a2ab0b@redhat.com [5]
Link: https://lore.kernel.org/all/ZnGa550k46ow2N3L@google.com [6]
Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Message-ID: <20240703021043.13881-1-yan.y.zhao@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-08-14 12:29:11 -04:00
Vignesh Balasubramanian
ba386777a3 x86/elf: Add a new FPU buffer layout info to x86 core files
Add a new .note section containing type, size, offset and flags of every
xfeature that is present.

This information will be used by debuggers to understand the XSAVE layout of
the machine where the core file has been dumped, and to read XSAVE registers,
especially during cross-platform debugging.

The XSAVE layouts of modern AMD and Intel CPUs differ, especially since
Memory Protection Keys and the AVX-512 features have been inculcated into
the AMD CPUs.

Since AMD never adopted (and hence never left room in the XSAVE layout for)
the Intel MPX feature, tools like GDB had assumed a fixed XSAVE layout
matching that of Intel (based on the XCR0 mask).

Hence, core dumps from AMD CPUs didn't match the known size for the XCR0 mask.
This resulted in GDB and other tools not being able to access the values of
the AVX-512 and PKRU registers on AMD CPUs.

To solve this, an interim solution has been accepted into GDB, and is already
a part of GDB 14, see

  https://sourceware.org/pipermail/gdb-patches/2023-March/198081.html.

But it depends on heuristics based on the total XSAVE register set size
and the XCR0 mask to infer the layouts of the various register blocks
for core dumps, and hence, is not a foolproof mechanism to determine the
layout of the XSAVE area.

Therefore, add a new core dump note in order to allow GDB/LLDB and other
relevant tools to determine the layout of the XSAVE area of the machine where
the corefile was dumped.

The new core dump note (which is being proposed as a per-process .note
section), NT_X86_XSAVE_LAYOUT (0x205) contains an array of structures.

Each structure describes an individual extended feature containing
offset, size and flags in this format:

  struct x86_xfeat_component {
         u32 type;
         u32 size;
         u32 offset;
         u32 flags;
  };

and in an independent manner, allowing for future extensions without depending
on hw arch specifics like CPUID etc.

  [ bp: Massage commit message, zap trailing whitespace. ]

Co-developed-by: Jini Susan George <jinisusan.george@amd.com>
Signed-off-by: Jini Susan George <jinisusan.george@amd.com>
Co-developed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Vignesh Balasubramanian <vigbalas@amd.com>
Link: https://lore.kernel.org/r/20240725161017.112111-2-vigbalas@amd.com
2024-07-29 10:45:43 +02:00
Linus Torvalds
2c9b351240 ARM:
* Initial infrastructure for shadow stage-2 MMUs, as part of nested
   virtualization enablement
 
 * Support for userspace changes to the guest CTR_EL0 value, enabling
   (in part) migration of VMs between heterogenous hardware
 
 * Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1 of
   the protocol
 
 * FPSIMD/SVE support for nested, including merged trap configuration
   and exception routing
 
 * New command-line parameter to control the WFx trap behavior under KVM
 
 * Introduce kCFI hardening in the EL2 hypervisor
 
 * Fixes + cleanups for handling presence/absence of FEAT_TCRX
 
 * Miscellaneous fixes + documentation updates
 
 LoongArch:
 
 * Add paravirt steal time support.
 
 * Add support for KVM_DIRTY_LOG_INITIALLY_SET.
 
 * Add perf kvm-stat support for loongarch.
 
 RISC-V:
 
 * Redirect AMO load/store access fault traps to guest
 
 * perf kvm stat support
 
 * Use guest files for IMSIC virtualization, when available
 
 ONE_REG support for the Zimop, Zcmop, Zca, Zcf, Zcd, Zcb and Zawrs ISA
 extensions is coming through the RISC-V tree.
 
 s390:
 
 * Assortment of tiny fixes which are not time critical
 
 x86:
 
 * Fixes for Xen emulation.
 
 * Add a global struct to consolidate tracking of host values, e.g. EFER
 
 * Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC
   bus frequency, because TDX.
 
 * Print the name of the APICv/AVIC inhibits in the relevant tracepoint.
 
 * Clean up KVM's handling of vendor specific emulation to consistently act on
   "compatible with Intel/AMD", versus checking for a specific vendor.
 
 * Drop MTRR virtualization, and instead always honor guest PAT on CPUs
   that support self-snoop.
 
 * Update to the newfangled Intel CPU FMS infrastructure.
 
 * Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as it reads
   '0' and writes from userspace are ignored.
 
 * Misc cleanups
 
 x86 - MMU:
 
 * Small cleanups, renames and refactoring extracted from the upcoming
   Intel TDX support.
 
 * Don't allocate kvm_mmu_page.shadowed_translation for shadow pages that can't
   hold leafs SPTEs.
 
 * Unconditionally drop mmu_lock when allocating TDP MMU page tables for eager
   page splitting, to avoid stalling vCPUs when splitting huge pages.
 
 * Bug the VM instead of simply warning if KVM tries to split a SPTE that is
   non-present or not-huge.  KVM is guaranteed to end up in a broken state
   because the callers fully expect a valid SPTE, it's all but dangerous
   to let more MMU changes happen afterwards.
 
 x86 - AMD:
 
 * Make per-CPU save_area allocations NUMA-aware.
 
 * Force sev_es_host_save_area() to be inlined to avoid calling into an
   instrumentable function from noinstr code.
 
 * Base support for running SEV-SNP guests.  API-wise, this includes
   a new KVM_X86_SNP_VM type, encrypting/measure the initial image into
   guest memory, and finalizing it before launching it.  Internally,
   there are some gmem/mmu hooks needed to prepare gmem-allocated pages
   before mapping them into guest private memory ranges.
 
   This includes basic support for attestation guest requests, enough to
   say that KVM supports the GHCB 2.0 specification.
 
   There is no support yet for loading into the firmware those signing
   keys to be used for attestation requests, and therefore no need yet
   for the host to provide certificate data for those keys.  To support
   fetching certificate data from userspace, a new KVM exit type will be
   needed to handle fetching the certificate from userspace. An attempt to
   define a new KVM_EXIT_COCO/KVM_EXIT_COCO_REQ_CERTS exit type to handle
   this was introduced in v1 of this patchset, but is still being discussed
   by community, so for now this patchset only implements a stub version
   of SNP Extended Guest Requests that does not provide certificate data.
 
 x86 - Intel:
 
 * Remove an unnecessary EPT TLB flush when enabling hardware.
 
 * Fix a series of bugs that cause KVM to fail to detect nested pending posted
   interrupts as valid wake eents for a vCPU executing HLT in L2 (with
   HLT-exiting disable by L1).
 
 * KVM: x86: Suppress MMIO that is triggered during task switch emulation
 
   Explicitly suppress userspace emulated MMIO exits that are triggered when
   emulating a task switch as KVM doesn't support userspace MMIO during
   complex (multi-step) emulation.  Silently ignoring the exit request can
   result in the WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to
   userspace for some other reason prior to purging mmio_needed.
 
   See commit 0dc902267c ("KVM: x86: Suppress pending MMIO write exits if
   emulator detects exception") for more details on KVM's limitations with
   respect to emulated MMIO during complex emulator flows.
 
 Generic:
 
 * Rename the AS_UNMOVABLE flag that was introduced for KVM to AS_INACCESSIBLE,
   because the special casing needed by these pages is not due to just
   unmovability (and in fact they are only unmovable because the CPU cannot
   access them).
 
 * New ioctl to populate the KVM page tables in advance, which is useful to
   mitigate KVM page faults during guest boot or after live migration.
   The code will also be used by TDX, but (probably) not through the ioctl.
 
 * Enable halt poll shrinking by default, as Intel found it to be a clear win.
 
 * Setup empty IRQ routing when creating a VM to avoid having to synchronize
   SRCU when creating a split IRQCHIP on x86.
 
 * Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag
   that arch code can use for hooking both sched_in() and sched_out().
 
 * Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
   truncating a bogus value from userspace, e.g. to help userspace detect bugs.
 
 * Mark a vCPU as preempted if and only if it's scheduled out while in the
   KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest
   memory when retrieving guest state during live migration blackout.
 
 Selftests:
 
 * Remove dead code in the memslot modification stress test.
 
 * Treat "branch instructions retired" as supported on all AMD Family 17h+ CPUs.
 
 * Print the guest pseudo-RNG seed only when it changes, to avoid spamming the
   log for tests that create lots of VMs.
 
 * Make the PMU counters test less flaky when counting LLC cache misses by
   doing CLFLUSH{OPT} in every loop iteration.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "ARM:

   - Initial infrastructure for shadow stage-2 MMUs, as part of nested
     virtualization enablement

   - Support for userspace changes to the guest CTR_EL0 value, enabling
     (in part) migration of VMs between heterogenous hardware

   - Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1
     of the protocol

   - FPSIMD/SVE support for nested, including merged trap configuration
     and exception routing

   - New command-line parameter to control the WFx trap behavior under
     KVM

   - Introduce kCFI hardening in the EL2 hypervisor

   - Fixes + cleanups for handling presence/absence of FEAT_TCRX

   - Miscellaneous fixes + documentation updates

  LoongArch:

   - Add paravirt steal time support

   - Add support for KVM_DIRTY_LOG_INITIALLY_SET

   - Add perf kvm-stat support for loongarch

  RISC-V:

   - Redirect AMO load/store access fault traps to guest

   - perf kvm stat support

   - Use guest files for IMSIC virtualization, when available

  s390:

   - Assortment of tiny fixes which are not time critical

  x86:

   - Fixes for Xen emulation

   - Add a global struct to consolidate tracking of host values, e.g.
     EFER

   - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the
     effective APIC bus frequency, because TDX

   - Print the name of the APICv/AVIC inhibits in the relevant
     tracepoint

   - Clean up KVM's handling of vendor specific emulation to
     consistently act on "compatible with Intel/AMD", versus checking
     for a specific vendor

   - Drop MTRR virtualization, and instead always honor guest PAT on
     CPUs that support self-snoop

   - Update to the newfangled Intel CPU FMS infrastructure

   - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as
     it reads '0' and writes from userspace are ignored

   - Misc cleanups

  x86 - MMU:

   - Small cleanups, renames and refactoring extracted from the upcoming
     Intel TDX support

   - Don't allocate kvm_mmu_page.shadowed_translation for shadow pages
     that can't hold leafs SPTEs

   - Unconditionally drop mmu_lock when allocating TDP MMU page tables
     for eager page splitting, to avoid stalling vCPUs when splitting
     huge pages

   - Bug the VM instead of simply warning if KVM tries to split a SPTE
     that is non-present or not-huge. KVM is guaranteed to end up in a
     broken state because the callers fully expect a valid SPTE, it's
     all but dangerous to let more MMU changes happen afterwards

  x86 - AMD:

   - Make per-CPU save_area allocations NUMA-aware

   - Force sev_es_host_save_area() to be inlined to avoid calling into
     an instrumentable function from noinstr code

   - Base support for running SEV-SNP guests. API-wise, this includes a
     new KVM_X86_SNP_VM type, encrypting/measure the initial image into
     guest memory, and finalizing it before launching it. Internally,
     there are some gmem/mmu hooks needed to prepare gmem-allocated
     pages before mapping them into guest private memory ranges

     This includes basic support for attestation guest requests, enough
     to say that KVM supports the GHCB 2.0 specification

     There is no support yet for loading into the firmware those signing
     keys to be used for attestation requests, and therefore no need yet
     for the host to provide certificate data for those keys.

     To support fetching certificate data from userspace, a new KVM exit
     type will be needed to handle fetching the certificate from
     userspace.

     An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS
     exit type to handle this was introduced in v1 of this patchset, but
     is still being discussed by community, so for now this patchset
     only implements a stub version of SNP Extended Guest Requests that
     does not provide certificate data

  x86 - Intel:

   - Remove an unnecessary EPT TLB flush when enabling hardware

   - Fix a series of bugs that cause KVM to fail to detect nested
     pending posted interrupts as valid wake eents for a vCPU executing
     HLT in L2 (with HLT-exiting disable by L1)

   - KVM: x86: Suppress MMIO that is triggered during task switch
     emulation

     Explicitly suppress userspace emulated MMIO exits that are
     triggered when emulating a task switch as KVM doesn't support
     userspace MMIO during complex (multi-step) emulation

     Silently ignoring the exit request can result in the
     WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace
     for some other reason prior to purging mmio_needed

     See commit 0dc902267c ("KVM: x86: Suppress pending MMIO write
     exits if emulator detects exception") for more details on KVM's
     limitations with respect to emulated MMIO during complex emulator
     flows

  Generic:

   - Rename the AS_UNMOVABLE flag that was introduced for KVM to
     AS_INACCESSIBLE, because the special casing needed by these pages
     is not due to just unmovability (and in fact they are only
     unmovable because the CPU cannot access them)

   - New ioctl to populate the KVM page tables in advance, which is
     useful to mitigate KVM page faults during guest boot or after live
     migration. The code will also be used by TDX, but (probably) not
     through the ioctl

   - Enable halt poll shrinking by default, as Intel found it to be a
     clear win

   - Setup empty IRQ routing when creating a VM to avoid having to
     synchronize SRCU when creating a split IRQCHIP on x86

   - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with
     a flag that arch code can use for hooking both sched_in() and
     sched_out()

   - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid
     truncating a bogus value from userspace, e.g. to help userspace
     detect bugs

   - Mark a vCPU as preempted if and only if it's scheduled out while in
     the KVM_RUN loop, e.g. to avoid marking it preempted and thus
     writing guest memory when retrieving guest state during live
     migration blackout

  Selftests:

   - Remove dead code in the memslot modification stress test

   - Treat "branch instructions retired" as supported on all AMD Family
     17h+ CPUs

   - Print the guest pseudo-RNG seed only when it changes, to avoid
     spamming the log for tests that create lots of VMs

   - Make the PMU counters test less flaky when counting LLC cache
     misses by doing CLFLUSH{OPT} in every loop iteration"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits)
  crypto: ccp: Add the SNP_VLEK_LOAD command
  KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops
  KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops
  KVM: x86: Replace static_call_cond() with static_call()
  KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event
  x86/sev: Move sev_guest.h into common SEV header
  KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event
  KVM: x86: Suppress MMIO that is triggered during task switch emulation
  KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro
  KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE
  KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY
  KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory()
  KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level
  KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault"
  KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler
  KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory
  KVM: Document KVM_PRE_FAULT_MEMORY ioctl
  mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE
  perf kvm: Add kvm-stat for loongarch64
  LoongArch: KVM: Add PV steal time support in guest side
  ...
2024-07-20 12:41:03 -07:00
Paolo Bonzini
5dcc1e7614 KVM x86 misc changes for 6.11
- Add a global struct to consolidate tracking of host values, e.g. EFER, and
    move "shadow_phys_bits" into the structure as "maxphyaddr".
 
  - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC
    bus frequency, because TDX.
 
  - Print the name of the APICv/AVIC inhibits in the relevant tracepoint.
 
  - Clean up KVM's handling of vendor specific emulation to consistently act on
    "compatible with Intel/AMD", versus checking for a specific vendor.
 
  - Misc cleanups
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Merge tag 'kvm-x86-misc-6.11' of https://github.com/kvm-x86/linux into HEAD

KVM x86 misc changes for 6.11

 - Add a global struct to consolidate tracking of host values, e.g. EFER, and
   move "shadow_phys_bits" into the structure as "maxphyaddr".

 - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC
   bus frequency, because TDX.

 - Print the name of the APICv/AVIC inhibits in the relevant tracepoint.

 - Clean up KVM's handling of vendor specific emulation to consistently act on
   "compatible with Intel/AMD", versus checking for a specific vendor.

 - Misc cleanups
2024-07-16 09:53:05 -04:00
Thomas Prescher
85542adb65 KVM: x86: Add KVM_RUN_X86_GUEST_MODE kvm_run flag
When a vCPU is interrupted by a signal while running a nested guest,
KVM will exit to userspace with L2 state. However, userspace has no
way to know whether it sees L1 or L2 state (besides calling
KVM_GET_STATS_FD, which does not have a stable ABI).

This causes multiple problems:

The simplest one is L2 state corruption when userspace marks the sregs
as dirty. See this mailing list thread [1] for a complete discussion.

Another problem is that if userspace decides to continue by emulating
instructions, it will unknowingly emulate with L2 state as if L1
doesn't exist, which can be considered a weird guest escape.

Introduce a new flag, KVM_RUN_X86_GUEST_MODE, in the kvm_run data
structure, which is set when the vCPU exited while running a nested
guest.  Also introduce a new capability, KVM_CAP_X86_GUEST_MODE, to
advertise the functionality to userspace.

[1] https://lore.kernel.org/kvm/20240416123558.212040-1-julian.stecklina@cyberus-technology.de/T/#m280aadcb2e10ae02c191a7dc4ed4b711a74b1f55

Signed-off-by: Thomas Prescher <thomas.prescher@cyberus-technology.de>
Signed-off-by: Julian Stecklina <julian.stecklina@cyberus-technology.de>
Link: https://lore.kernel.org/r/20240508132502.184428-1-julian.stecklina@cyberus-technology.de
Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-06-11 09:24:31 -07:00
Tom Lendacky
34ff659017 x86/sev: Use kernel provided SVSM Calling Areas
The SVSM Calling Area (CA) is used to communicate between Linux and the
SVSM. Since the firmware supplied CA for the BSP is likely to be in
reserved memory, switch off that CA to a kernel provided CA so that access
and use of the CA is available during boot. The CA switch is done using
the SVSM core protocol SVSM_CORE_REMAP_CA call.

An SVSM call is executed by filling out the SVSM CA and setting the proper
register state as documented by the SVSM protocol. The SVSM is invoked by
by requesting the hypervisor to run VMPL0.

Once it is safe to allocate/reserve memory, allocate a CA for each CPU.
After allocating the new CAs, the BSP will switch from the boot CA to the
per-CPU CA. The CA for an AP is identified to the SVSM when creating the
VMSA in preparation for booting the AP.

  [ bp: Heavily simplify svsm_issue_call() asm, other touchups. ]

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/fa8021130bcc3bcf14d722a25548cb0cdf325456.1717600736.git.thomas.lendacky@amd.com
2024-06-11 07:22:46 +02:00
Brijesh Singh
ad27ce1555 KVM: SEV: Add KVM_SEV_SNP_LAUNCH_FINISH command
Add a KVM_SEV_SNP_LAUNCH_FINISH command to finalize the cryptographic
launch digest which stores the measurement of the guest at launch time.
Also extend the existing SNP firmware data structures to support
disabling the use of Versioned Chip Endorsement Keys (VCEK) by guests as
part of this command.

While finalizing the launch flow, the code also issues the LAUNCH_UPDATE
SNP firmware commands to encrypt/measure the initial VMSA pages for each
configured vCPU, which requires setting the RMP entries for those pages
to private, so also add handling to clean up the RMP entries for these
pages whening freeing vCPUs during shutdown.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Harald Hoyer <harald@profian.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Message-ID: <20240501085210.2213060-8-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-12 04:09:30 -04:00
Brijesh Singh
dee5a47cc7 KVM: SEV: Add KVM_SEV_SNP_LAUNCH_UPDATE command
A key aspect of a launching an SNP guest is initializing it with a
known/measured payload which is then encrypted into guest memory as
pre-validated private pages and then measured into the cryptographic
launch context created with KVM_SEV_SNP_LAUNCH_START so that the guest
can attest itself after booting.

Since all private pages are provided by guest_memfd, make use of the
kvm_gmem_populate() interface to handle this. The general flow is that
guest_memfd will handle allocating the pages associated with the GPA
ranges being initialized by each particular call of
KVM_SEV_SNP_LAUNCH_UPDATE, copying data from userspace into those pages,
and then the post_populate callback will do the work of setting the
RMP entries for these pages to private and issuing the SNP firmware
calls to encrypt/measure them.

For more information see the SEV-SNP specification.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Message-ID: <20240501085210.2213060-7-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-12 04:09:29 -04:00
Brijesh Singh
136d8bc931 KVM: SEV: Add KVM_SEV_SNP_LAUNCH_START command
KVM_SEV_SNP_LAUNCH_START begins the launch process for an SEV-SNP guest.
The command initializes a cryptographic digest context used to construct
the measurement of the guest. Other commands can then at that point be
used to load/encrypt data into the guest's initial launch image.

For more information see the SEV-SNP specification.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Message-ID: <20240501085210.2213060-6-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-12 04:09:29 -04:00
Brijesh Singh
1dfe571c12 KVM: SEV: Add initial SEV-SNP support
SEV-SNP builds upon existing SEV and SEV-ES functionality while adding
new hardware-based security protection. SEV-SNP adds strong memory
encryption and integrity protection to help prevent malicious
hypervisor-based attacks such as data replay, memory re-mapping, and
more, to create an isolated execution environment.

Define a new KVM_X86_SNP_VM type which makes use of these capabilities
and extend the KVM_SEV_INIT2 ioctl to support it. Also add a basic
helper to check whether SNP is enabled and set PFERR_PRIVATE_ACCESS for
private #NPFs so they are handled appropriately by KVM MMU.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Co-developed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20240501085210.2213060-5-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-12 04:09:28 -04:00
Michael Roth
4af663c2f6 KVM: SEV: Allow per-guest configuration of GHCB protocol version
The GHCB protocol version may be different from one guest to the next.
Add a field to track it for each KVM instance and extend KVM_SEV_INIT2
to allow it to be configured by userspace.

Now that all SEV-ES support for GHCB protocol version 2 is in place, go
ahead and default to it when creating SEV-ES guests through the new
KVM_SEV_INIT2 interface. Keep the older KVM_SEV_ES_INIT interface
restricted to GHCB protocol version 1.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Message-ID: <20240501071048.2208265-5-michael.roth@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-05-07 13:28:05 -04:00
Paolo Bonzini
4f5defae70 KVM: SEV: introduce KVM_SEV_INIT2 operation
The idea that no parameter would ever be necessary when enabling SEV or
SEV-ES for a VM was decidedly optimistic.  In fact, in some sense it's
already a parameter whether SEV or SEV-ES is desired.  Another possible
source of variability is the desired set of VMSA features, as that affects
the measurement of the VM's initial state and cannot be changed
arbitrarily by the hypervisor.

Create a new sub-operation for KVM_MEMORY_ENCRYPT_OP that can take a struct,
and put the new op to work by including the VMSA features as a field of the
struct.  The existing KVM_SEV_INIT and KVM_SEV_ES_INIT use the full set of
supported VMSA features for backwards compatibility.

The struct also includes the usual bells and whistles for future
extensibility: a flags field that must be zero for now, and some padding
at the end.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20240404121327.3107131-13-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11 13:08:25 -04:00
Paolo Bonzini
26c44aa9e0 KVM: SEV: define VM types for SEV and SEV-ES
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20240404121327.3107131-11-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11 13:08:25 -04:00
Paolo Bonzini
ac5c48027b KVM: SEV: publish supported VMSA features
Compute the set of features to be stored in the VMSA when KVM is
initialized; move it from there into kvm_sev_info when SEV is initialized,
and then into the initial VMSA.

The new variable can then be used to return the set of supported features
to userspace, via the KVM_GET_DEVICE_ATTR ioctl.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Message-ID: <20240404121327.3107131-6-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-04-11 13:08:22 -04:00