* New features:
- Support for non-protected guest in protected mode, achieving near
feature parity with the non-protected mode
- Support for the EL2 timers as part of the ongoing NV support
- Allow control of hardware tracing for nVHE/hVHE
* Improvements, fixes and cleanups:
- Massive cleanup of the debug infrastructure, making it a bit less
awkward and definitely easier to maintain. This should pave the
way for further optimisations
- Complete rewrite of pKVM's fixed-feature infrastructure, aligning
it with the rest of KVM and making the code easier to follow
- Large simplification of pKVM's memory protection infrastructure
- Better handling of RES0/RES1 fields for memory-backed system
registers
- Add a workaround for Qualcomm's Snapdragon X CPUs, which suffer
from a pretty nasty timer bug
- Small collection of cleanups and low-impact fixes
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull KVM/arm64 updates from Will Deacon:
"New features:
- Support for non-protected guest in protected mode, achieving near
feature parity with the non-protected mode
- Support for the EL2 timers as part of the ongoing NV support
- Allow control of hardware tracing for nVHE/hVHE
Improvements, fixes and cleanups:
- Massive cleanup of the debug infrastructure, making it a bit less
awkward and definitely easier to maintain. This should pave the way
for further optimisations
- Complete rewrite of pKVM's fixed-feature infrastructure, aligning
it with the rest of KVM and making the code easier to follow
- Large simplification of pKVM's memory protection infrastructure
- Better handling of RES0/RES1 fields for memory-backed system
registers
- Add a workaround for Qualcomm's Snapdragon X CPUs, which suffer
from a pretty nasty timer bug
- Small collection of cleanups and low-impact fixes"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (87 commits)
arm64/sysreg: Get rid of TRFCR_ELx SysregFields
KVM: arm64: nv: Fix doc header layout for timers
KVM: arm64: nv: Apply RESx settings to sysreg reset values
KVM: arm64: nv: Always evaluate HCR_EL2 using sanitising accessors
KVM: arm64: Fix selftests after sysreg field name update
coresight: Pass guest TRFCR value to KVM
KVM: arm64: Support trace filtering for guests
KVM: arm64: coresight: Give TRBE enabled state to KVM
coresight: trbe: Remove redundant disable call
arm64/sysreg/tools: Move TRFCR definitions to sysreg
tools: arm64: Update sysreg.h header files
KVM: arm64: Drop pkvm_mem_transition for host/hyp donations
KVM: arm64: Drop pkvm_mem_transition for host/hyp sharing
KVM: arm64: Drop pkvm_mem_transition for FF-A
KVM: arm64: Explicitly handle BRBE traps as UNDEFINED
KVM: arm64: vgic: Use str_enabled_disabled() in vgic_v3_probe()
arm64: kvm: Introduce nvhe stack size constants
KVM: arm64: Fix nVHE stacktrace VA bits mask
KVM: arm64: Fix FEAT_MTE in pKVM
Documentation: Update the behaviour of "kvm-arm.mode"
...
To determine CPU features during initialization, the nVHE hypervisor
utilizes sanitized values of the host's CPU features registers. These
values, stored in u64 idaa64*_el1_sys_val variables are updated by the
kvm_hyp_init_symbols() function at EL1. To ensure EL2 visibility with
the MMU off, the data cache needs to be flushed after these updates.
However, individually flushing each variable using
kvm_flush_dcache_to_poc() is inefficient.
These cpu feature variables would be part of the bss section of
the hypervisor. Hence, flush the entire bss section of hypervisor
once the initialization is complete.
Fixes: 6c30bfb18d ("KVM: arm64: Add handlers for protected VM System Registers")
Suggested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@google.com>
Link: https://lore.kernel.org/r/20250121044016.2219256-1-lokeshvutla@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/misc-6.14:
: .
: Misc KVM/arm64 changes for 6.14
:
: - Don't expose AArch32 EL0 capability when NV is enabled
:
: - Update documentation to reflect the full gamut of kvm-arm.mode
: behaviours
:
: - Use the hypervisor VA bit width when dumping stacktraces
:
: - Decouple the hypervisor stack size from PAGE_SIZE, at least
: on the surface...
:
: - Make use of str_enabled_disabled() when advertising GICv4.1 support
:
: - Explicitly handle BRBE traps as UNDEFINED
: .
KVM: arm64: Explicitly handle BRBE traps as UNDEFINED
KVM: arm64: vgic: Use str_enabled_disabled() in vgic_v3_probe()
arm64: kvm: Introduce nvhe stack size constants
KVM: arm64: Fix nVHE stacktrace VA bits mask
Documentation: Update the behaviour of "kvm-arm.mode"
KVM: arm64: nv: Advertise the lack of AArch32 EL0 support
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/nv-timers:
: .
: Nested Virt support for the EL2 timers. From the initial cover letter:
:
: "Here's another batch of NV-related patches, this time bringing in most
: of the timer support for EL2 as well as nested guests.
:
: The code is pretty convoluted for a bunch of reasons:
:
: - FEAT_NV2 breaks the timer semantics by redirecting HW controls to
: memory, meaning that a guest could setup a timer and never see it
: firing until the next exit
:
: - We go try hard to reflect the timer state in memory, but that's not
: great.
:
: - With FEAT_ECV, we can finally correctly emulate the virtual timer,
: but this emulation is pretty costly
:
: - As a way to make things suck less, we handle timer reads as early as
: possible, and only defer writes to the normal trap handling
:
: - Finally, some implementations are badly broken, and require some
: hand-holding, irrespective of NV support. So we try and reuse the NV
: infrastructure to make them usable. This could be further optimised,
: but I'm running out of patience for this sort of HW.
:
: [...]"
: .
KVM: arm64: nv: Fix doc header layout for timers
KVM: arm64: nv: Document EL2 timer API
KVM: arm64: Work around x1e's CNTVOFF_EL2 bogosity
KVM: arm64: nv: Sanitise CNTHCTL_EL2
KVM: arm64: nv: Propagate CNTHCTL_EL2.EL1NV{P,V}CT bits
KVM: arm64: nv: Add trap routing for CNTHCTL_EL2.EL1{NVPCT,NVVCT,TVT,TVCT}
KVM: arm64: Handle counter access early in non-HYP context
KVM: arm64: nv: Accelerate EL0 counter accesses from hypervisor context
KVM: arm64: nv: Accelerate EL0 timer read accesses when FEAT_ECV in use
KVM: arm64: nv: Use FEAT_ECV to trap access to EL0 timers
KVM: arm64: nv: Publish emulated timer interrupt state in the in-memory state
KVM: arm64: nv: Sync nested timer state with FEAT_NV2
KVM: arm64: nv: Add handling of EL2-specific timer registers
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/pkvm-fixed-features-6.14: (24 commits)
: .
: Complete rework of the pKVM handling of features, catching up
: with the rest of the code deals with it these days.
: Patches courtesy of Fuad Tabba. From the cover letter:
:
: "This patch series uses the vm's feature id registers to track the
: supported features, a framework similar to nested virt to set the
: trap values, and removes the need to store cptr_el2 per vcpu in
: favor of setting its value when traps are activated, as VHE mode
: does."
:
: This branch drags the arm64/for-next/cpufeature branch to solve
: ugly conflicts in -next.
: .
KVM: arm64: Fix FEAT_MTE in pKVM
KVM: arm64: Use kvm_vcpu_has_feature() directly for struct kvm
KVM: arm64: Convert the SVE guest vcpu flag to a vm flag
KVM: arm64: Remove PtrAuth guest vcpu flag
KVM: arm64: Fix the value of the CPTR_EL2 RES1 bitmask for nVHE
KVM: arm64: Refactor kvm_reset_cptr_el2()
KVM: arm64: Calculate cptr_el2 traps on activating traps
KVM: arm64: Remove redundant setting of HCR_EL2 trap bit
KVM: arm64: Remove fixed_config.h header
KVM: arm64: Rework specifying restricted features for protected VMs
KVM: arm64: Set protected VM traps based on its view of feature registers
KVM: arm64: Fix RAS trapping in pKVM for protected VMs
KVM: arm64: Initialize feature id registers for protected VMs
KVM: arm64: Use KVM extension checks for allowed protected VM capabilities
KVM: arm64: Remove KVM_ARM_VCPU_POWER_OFF from protected VMs allowed features in pKVM
KVM: arm64: Move checking protected vcpu features to a separate function
KVM: arm64: Group setting traps for protected VMs by control register
KVM: arm64: Consolidate allowed and restricted VM feature checks
arm64/sysreg: Get rid of CPACR_ELx SysregFields
arm64/sysreg: Convert *_EL12 accessors to Mapping
...
Signed-off-by: Marc Zyngier <maz@kernel.org>
# Conflicts:
# arch/arm64/kvm/fpsimd.c
# arch/arm64/kvm/hyp/nvhe/pkvm.c
* kvm-arm64/pkvm-np-guest:
: .
: pKVM support for non-protected guests using the standard MM
: infrastructure, courtesy of Quentin Perret. From the cover letter:
:
: "This series moves the stage-2 page-table management of non-protected
: guests to EL2 when pKVM is enabled. This is only intended as an
: incremental step towards a 'feature-complete' pKVM, there is however a
: lot more that needs to come on top.
:
: With that series applied, pKVM provides near-parity with standard KVM
: from a functional perspective all while Linux no longer touches the
: stage-2 page-tables itself at EL1. The majority of mm-related KVM
: features work out of the box, including MMU notifiers, dirty logging,
: RO memslots and things of that nature. There are however two gotchas:
:
: - We don't support mapping devices into guests: this requires
: additional hypervisor support for tracking the 'state' of devices,
: which will come in a later series. No device assignment until then.
:
: - Stage-2 mappings are forced to page-granularity even when backed by a
: huge page for the sake of simplicity of this series. I'm only aiming
: at functional parity-ish (from userspace's PoV) for now, support for
: HP can be added on top later as a perf improvement."
: .
KVM: arm64: Plumb the pKVM MMU in KVM
KVM: arm64: Introduce the EL1 pKVM MMU
KVM: arm64: Introduce __pkvm_tlb_flush_vmid()
KVM: arm64: Introduce __pkvm_host_mkyoung_guest()
KVM: arm64: Introduce __pkvm_host_test_clear_young_guest()
KVM: arm64: Introduce __pkvm_host_wrprotect_guest()
KVM: arm64: Introduce __pkvm_host_relax_guest_perms()
KVM: arm64: Introduce __pkvm_host_unshare_guest()
KVM: arm64: Introduce __pkvm_host_share_guest()
KVM: arm64: Introduce __pkvm_vcpu_{load,put}()
KVM: arm64: Add {get,put}_pkvm_hyp_vm() helpers
KVM: arm64: Make kvm_pgtable_stage2_init() a static inline function
KVM: arm64: Pass walk flags to kvm_pgtable_stage2_relax_perms
KVM: arm64: Pass walk flags to kvm_pgtable_stage2_mkyoung
KVM: arm64: Move host page ownership tracking to the hyp vmemmap
KVM: arm64: Make hyp_page::order a u8
KVM: arm64: Move enum pkvm_page_state to memory.h
KVM: arm64: Change the layout of enum pkvm_page_state
Signed-off-by: Marc Zyngier <maz@kernel.org>
# Conflicts:
# arch/arm64/kvm/arm.c
Refactor nvhe stack code to use NVHE_STACK_SIZE/SHIFT constants,
instead of directly using PAGE_SIZE/SHIFT. This makes the code a bit
easier to read, without introducing any functional changes.
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Link: https://lore.kernel.org/r/20241112003336.1375584-1-kaleshsingh@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
With FEAT_NV2, the EL0 timer state is entirely stored in memory,
meaning that the hypervisor can only provide a very poor emulation.
The only thing we can really do is to publish the interrupt state
in the guest view of CNT{P,V}_CTL_EL0, and defer everything else
to the next exit.
Only FEAT_ECV will allow us to fix it, at the cost of extra trapping.
Suggested-by: Chase Conklin <chase.conklin@arm.com>
Suggested-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241217142321.763801-4-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Emulating the timers with FEAT_NV2 is a bit odd, as the timers
can be reconfigured behind our back without the hypervisor even
noticing. In the VHE case, that's an actual regression in the
architecture...
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241217142321.763801-3-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Similar to VHE, calculate the value of cptr_el2 from scratch on
activate traps. This removes the need to store cptr_el2 in every
vcpu structure. Moreover, some traps, such as whether the guest
owns the fp registers, need to be set on every vcpu run.
Reported-by: James Clark <james.clark@linaro.org>
Fixes: 5294afdbf4 ("KVM: arm64: Exclude FP ownership from kvm_vcpu_arch")
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20241216105057.579031-13-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Use KVM extension checks as the source for determining which
capabilities are allowed for protected VMs. KVM extension checks
is the natural place for this, since it is also the interface
exposed to users.
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20241216105057.579031-6-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Introduce the KVM_PGT_CALL() helper macro to allow switching from the
traditional pgtable code to the pKVM version easily in mmu.c. The cost
of this 'indirection' is expected to be very minimal due to
is_protected_kvm_enabled() being backed by a static key.
With this, everything is in place to allow the delegation of
non-protected guest stage-2 page-tables to pKVM, so let's stop using the
host's kvm_s2_mmu from EL2 and enjoy the ride.
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20241218194059.3670226-19-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Rather than look-up the hyp vCPU on every run hypercall at EL2,
introduce a per-CPU 'loaded_hyp_vcpu' tracking variable which is updated
by a pair of load/put hypercalls called directly from
kvm_arch_vcpu_{load,put}() when pKVM is enabled.
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20241218194059.3670226-10-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
KVM takes over the guest's software step state machine if the VMM is
debugging the guest, but it does the save/restore fiddling for every
guest entry.
Note that the only constraint on host usage of software step is that the
guest's configuration remains visible to userspace via the ONE_REG
ioctls. So, we can cut down on the amount of fiddling by doing this at
load/put instead.
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-16-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
KVM has picked up several hacks to cope with vcpu->arch.mdcr_el2 needing
to be prepared before vcpu_load(), which is when it gets programmed
into hardware on VHE.
Now that the flows for reprogramming MDCR_EL2 have been simplified, move
that computation to vcpu_load().
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-14-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
Delete the remnants of debug_ptr now that debug registers are selected
based on the debug owner instead.
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-11-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
In preparation for tossing the debug_ptr mess, introduce an enumeration
to track the ownership of the debug registers while in the guest. Update
the owner at vcpu_load() based on whether the host needs to steal the
guest's debug context or if breakpoints/watchpoints are actively in use.
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-7-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
Add flags to kvm_host_data to track if SPE/TRBE is present +
programmable on a per-CPU basis. Set the flags up at init rather than
vcpu_load() as the programmability of these buffers is unlikely to
change.
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
KVM caches MDCR_EL2 on a per-CPU basis in order to preserve the
configuration of MDCR_EL2.HPMN while running a guest. This is a bit
gross, since we're relying on some baked configuration rather than the
hardware definition of implemented counters.
Discover the number of implemented counters by reading PMCR_EL0.N
instead. This works because:
- In VHE the kernel runs at EL2, and N always returns the number of
counters implemented in hardware
- In {n,h}VHE, the EL2 setup code programs MDCR_EL2.HPMN with the EL2
view of PMCR_EL0.N for the host
Lastly, avoid traps under nested virtualization by saving PMCR_EL0.N in
host data.
Tested-by: James Clark <james.clark@linaro.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-3-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
When the host stage1 is configured for LPA2, the value currently being
programmed into TCR_EL2.T0SZ may be invalid unless LPA2 is configured
at HYP as well. This means kvm_lpa2_is_enabled() is not the right
condition to test when setting TCR_EL2.DS, as it will return false if
LPA2 is only available for stage 1 but not for stage 2.
Similary, programming TCR_EL2.PS based on a limited IPA range due to
lack of stage2 LPA2 support could potentially result in problems.
So use lpa2_is_enabled() instead, and set the PS field according to the
host's IPS, which is capped at 48 bits if LPA2 support is absent or
disabled. Whether or not we can make meaningful use of such a
configuration is a different question.
Cc: stable@vger.kernel.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20241212081841.2168124-11-ardb+git@google.com
Signed-off-by: Will Deacon <will@kernel.org>
* kvm-arm64/misc:
: Miscellaneous updates
:
: - Drop useless check against vgic state in ICC_CLTR_EL1.SEIS read
: emulation
:
: - Fix trap configuration for pKVM
:
: - Close the door on initialization bugs surrounding userspace irqchip
: static key by removing it.
KVM: selftests: Don't bother deleting memslots in KVM when freeing VMs
KVM: arm64: Get rid of userspace_irqchip_in_use
KVM: arm64: Initialize trap register values in hyp in pKVM
KVM: arm64: Initialize the hypervisor's VM state at EL2
KVM: arm64: Refactor kvm_vcpu_enable_ptrauth() for hyp use
KVM: arm64: Move pkvm_vcpu_init_traps() to init_pkvm_hyp_vcpu()
KVM: arm64: Don't map 'kvm_vgic_global_state' at EL2 with pKVM
KVM: arm64: Just advertise SEIS as 0 when emulating ICC_CTLR_EL1
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Improper use of userspace_irqchip_in_use led to syzbot hitting the
following WARN_ON() in kvm_timer_update_irq():
WARNING: CPU: 0 PID: 3281 at arch/arm64/kvm/arch_timer.c:459
kvm_timer_update_irq+0x21c/0x394
Call trace:
kvm_timer_update_irq+0x21c/0x394 arch/arm64/kvm/arch_timer.c:459
kvm_timer_vcpu_reset+0x158/0x684 arch/arm64/kvm/arch_timer.c:968
kvm_reset_vcpu+0x3b4/0x560 arch/arm64/kvm/reset.c:264
kvm_vcpu_set_target arch/arm64/kvm/arm.c:1553 [inline]
kvm_arch_vcpu_ioctl_vcpu_init arch/arm64/kvm/arm.c:1573 [inline]
kvm_arch_vcpu_ioctl+0x112c/0x1b3c arch/arm64/kvm/arm.c:1695
kvm_vcpu_ioctl+0x4ec/0xf74 virt/kvm/kvm_main.c:4658
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__arm64_sys_ioctl+0x108/0x184 fs/ioctl.c:893
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x78/0x1b8 arch/arm64/kernel/syscall.c:49
el0_svc_common+0xe8/0x1b0 arch/arm64/kernel/syscall.c:132
do_el0_svc+0x40/0x50 arch/arm64/kernel/syscall.c:151
el0_svc+0x54/0x14c arch/arm64/kernel/entry-common.c:712
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
The following sequence led to the scenario:
- Userspace creates a VM and a vCPU.
- The vCPU is initialized with KVM_ARM_VCPU_PMU_V3 during
KVM_ARM_VCPU_INIT.
- Without any other setup, such as vGIC or vPMU, userspace issues
KVM_RUN on the vCPU. Since the vPMU is requested, but not setup,
kvm_arm_pmu_v3_enable() fails in kvm_arch_vcpu_run_pid_change().
As a result, KVM_RUN returns after enabling the timer, but before
incrementing 'userspace_irqchip_in_use':
kvm_arch_vcpu_run_pid_change()
ret = kvm_arm_pmu_v3_enable()
if (!vcpu->arch.pmu.created)
return -EINVAL;
if (ret)
return ret;
[...]
if (!irqchip_in_kernel(kvm))
static_branch_inc(&userspace_irqchip_in_use);
- Userspace ignores the error and issues KVM_ARM_VCPU_INIT again.
Since the timer is already enabled, control moves through the
following flow, ultimately hitting the WARN_ON():
kvm_timer_vcpu_reset()
if (timer->enabled)
kvm_timer_update_irq()
if (!userspace_irqchip())
ret = kvm_vgic_inject_irq()
ret = vgic_lazy_init()
if (unlikely(!vgic_initialized(kvm)))
if (kvm->arch.vgic.vgic_model !=
KVM_DEV_TYPE_ARM_VGIC_V2)
return -EBUSY;
WARN_ON(ret);
Theoretically, since userspace_irqchip_in_use's functionality can be
simply replaced by '!irqchip_in_kernel()', get rid of the static key
to avoid the mismanagement, which also helps with the syzbot issue.
Cc: <stable@vger.kernel.org>
Reported-by: syzbot <syzkaller@googlegroups.com>
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Move pkvm_vcpu_init_traps() to the initialization of the
hypervisor's vcpu state in init_pkvm_hyp_vcpu(), and remove the
associated hypercall.
In protected mode, traps need to be initialized whenever a VCPU
is initialized anyway, and not only for protected VMs. This also
saves an unnecessary hypercall.
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20241018074833.2563674-2-tabba@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
As there is very little ordering in the KVM API, userspace can
instanciate a half-baked GIC (missing its memory map, for example)
at almost any time.
This means that, with the right timing, a thread running vcpu-0
can enter the kernel without a GIC configured and get a GIC created
behind its back by another thread. Amusingly, it will pick up
that GIC and start messing with the data structures without the
GIC having been fully initialised.
Similarly, a thread running vcpu-1 can enter the kernel, and try
to init the GIC that was previously created. Since this GIC isn't
properly configured (no memory map), it fails to correctly initialise.
And that's the point where we decide to teardown the GIC, freeing all
its resources. Behind vcpu-0's back. Things stop pretty abruptly,
with a variety of symptoms. Clearly, this isn't good, we should be
a bit more careful about this.
It is obvious that this guest is not viable, as it is missing some
important part of its configuration. So instead of trying to tear
bits of it down, let's just mark it as *dead*. It means that any
further interaction from userspace will result in -EIO. The memory
will be released on the "normal" path, when userspace gives up.
Cc: stable@vger.kernel.org
Reported-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241009183603.3221824-1-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Currently, when a nested MMU is repurposed for some other MMU context,
KVM unmaps everything during vcpu_load() while holding the MMU lock for
write. This is quite a performance bottleneck for large nested VMs, as
all vCPU scheduling will spin until the unmap completes.
Start punting the MMU cleanup to a vCPU request, where it is then
possible to periodically release the MMU lock and CPU in the presence of
contention.
Ensure that no vCPU winds up using a stale MMU by tracking the pending
unmap on the S2 MMU itself and requesting an unmap on every vCPU that
finds it.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241007233028.2236133-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
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.
The primary motivation for this series is to simplify dealing with enabling
virtualization for Intel's TDX, which needs to enable virtualization
when kvm-intel.ko is loaded, i.e. long before the first VM is created.
That said, this is a nice cleanup on its own. By registering the callbacks
on-demand, the callbacks themselves don't need to check kvm_usage_count,
because their very existence implies a non-zero count.
Patch 1 (re)adds a dedicated lock for kvm_usage_count. This avoids a
lock ordering issue between cpus_read_lock() and kvm_lock. The lock
ordering issue still exist in very rare cases, and will be fixed for
good by switching vm_list to an (S)RCU-protected list.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kvm-arm64/s2-ptdump:
: .
: Stage-2 page table dumper, reusing the main ptdump infrastructure,
: courtesy of Sebastian Ene. From the cover letter:
:
: "This series extends the ptdump support to allow dumping the guest
: stage-2 pagetables. When CONFIG_PTDUMP_STAGE2_DEBUGFS is enabled, ptdump
: registers the new following files under debugfs:
: - /sys/debug/kvm/<guest_id>/stage2_page_tables
: - /sys/debug/kvm/<guest_id>/stage2_levels
: - /sys/debug/kvm/<guest_id>/ipa_range
:
: This allows userspace tools (eg. cat) to dump the stage-2 pagetables by
: reading the 'stage2_page_tables' file.
: [...]"
: .
KVM: arm64: Register ptdump with debugfs on guest creation
arm64: ptdump: Don't override the level when operating on the stage-2 tables
arm64: ptdump: Use the ptdump description from a local context
arm64: ptdump: Expose the attribute parsing functionality
KVM: arm64: Move pagetable definitions to common header
Signed-off-by: Marc Zyngier <maz@kernel.org>
While arch/*/mem/ptdump handles the kernel pagetable dumping code,
introduce KVM/ptdump to show the guest stage-2 pagetables. The
separation is necessary because most of the definitions from the
stage-2 pagetable reside in the KVM path and we will be invoking
functionality specific to KVM. Introduce the PTDUMP_STAGE2_DEBUGFS config.
When a guest is created, register a new file entry under the guest
debugfs dir which allows userspace to show the contents of the guest
stage-2 pagetables when accessed.
[maz: moved function prototypes from kvm_host.h to kvm_mmu.h]
Signed-off-by: Sebastian Ene <sebastianene@google.com>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20240909124721.1672199-6-sebastianene@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Rename the per-CPU hooks used to enable virtualization in hardware to
align with the KVM-wide helpers in kvm_main.c, and to better capture that
the callbacks are invoked on every online CPU.
No functional change intended.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Message-ID: <20240830043600.127750-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We already have to perform a set of last-chance adjustments for
NV purposes. We will soon have to do the same for the GIC, so
introduce a helper for that exact purpose.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240827152517.3909653-5-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Tidy up some of the PAuth trapping code to clear up some comments
and avoid clang/checkpatch warnings. Also, don't bother setting
PAuth HCR_EL2 bits in pKVM, since it's handled by the hypervisor.
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20240722163311.1493879-1-tabba@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Fix kdoc warnings by adding missing function parameter
descriptions or by conversion to a normal comment.
Signed-off-by: Sebastian Ott <sebott@redhat.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240723101204.7356-3-sebott@redhat.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
- 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.
- A few minor cleanups
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Merge tag 'kvm-x86-generic-6.11' of https://github.com/kvm-x86/linux into HEAD
KVM generic changes for 6.11
- 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.
- A few minor cleanups
* kvm-arm64/nv-sve:
: CPTR_EL2, FPSIMD/SVE support for nested
:
: This series brings support for honoring the guest hypervisor's CPTR_EL2
: trap configuration when running a nested guest, along with support for
: FPSIMD/SVE usage at L1 and L2.
KVM: arm64: Allow the use of SVE+NV
KVM: arm64: nv: Add additional trap setup for CPTR_EL2
KVM: arm64: nv: Add trap description for CPTR_EL2
KVM: arm64: nv: Add TCPAC/TTA to CPTR->CPACR conversion helper
KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2
KVM: arm64: nv: Load guest FP state for ZCR_EL2 trap
KVM: arm64: nv: Handle CPACR_EL1 traps
KVM: arm64: Spin off helper for programming CPTR traps
KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state
KVM: arm64: nv: Use guest hypervisor's max VL when running nested guest
KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context
KVM: arm64: nv: Load guest hyp's ZCR into EL1 state
KVM: arm64: nv: Handle ZCR_EL2 traps
KVM: arm64: nv: Forward SVE traps to guest hypervisor
KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/ctr-el0:
: Support for user changes to CTR_EL0, courtesy of Sebastian Ott
:
: Allow userspace to change the guest-visible value of CTR_EL0 for a VM,
: so long as the requested value represents a subset of features supported
: by hardware. In other words, prevent the VMM from over-promising the
: capabilities of hardware.
:
: Make this happen by fitting CTR_EL0 into the existing infrastructure for
: feature ID registers.
KVM: selftests: Assert that MPIDR_EL1 is unchanged across vCPU reset
KVM: arm64: nv: Unfudge ID_AA64PFR0_EL1 masking
KVM: selftests: arm64: Test writes to CTR_EL0
KVM: arm64: rename functions for invariant sys regs
KVM: arm64: show writable masks for feature registers
KVM: arm64: Treat CTR_EL0 as a VM feature ID register
KVM: arm64: unify code to prepare traps
KVM: arm64: nv: Use accessors for modifying ID registers
KVM: arm64: Add helper for writing ID regs
KVM: arm64: Use read-only helper for reading VM ID registers
KVM: arm64: Make idregs debugfs iterator search sysreg table directly
KVM: arm64: Get sys_reg encoding from descriptor in idregs_debug_show()
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/shadow-mmu:
: Shadow stage-2 MMU support for NV, courtesy of Marc Zyngier
:
: Initial implementation of shadow stage-2 page tables to support a guest
: hypervisor. In the author's words:
:
: So here's the 10000m (approximately 30000ft for those of you stuck
: with the wrong units) view of what this is doing:
:
: - for each {VMID,VTTBR,VTCR} tuple the guest uses, we use a
: separate shadow s2_mmu context. This context has its own "real"
: VMID and a set of page tables that are the combination of the
: guest's S2 and the host S2, built dynamically one fault at a time.
:
: - these shadow S2 contexts are ephemeral, and behave exactly as
: TLBs. For all intent and purposes, they *are* TLBs, and we discard
: them pretty often.
:
: - TLB invalidation takes three possible paths:
:
: * either this is an EL2 S1 invalidation, and we directly emulate
: it as early as possible
:
: * or this is an EL1 S1 invalidation, and we need to apply it to
: the shadow S2s (plural!) that match the VMID set by the L1 guest
:
: * or finally, this is affecting S2, and we need to teardown the
: corresponding part of the shadow S2s, which invalidates the TLBs
KVM: arm64: nv: Truely enable nXS TLBI operations
KVM: arm64: nv: Add handling of NXS-flavoured TLBI operations
KVM: arm64: nv: Add handling of range-based TLBI operations
KVM: arm64: nv: Add handling of outer-shareable TLBI operations
KVM: arm64: nv: Invalidate TLBs based on shadow S2 TTL-like information
KVM: arm64: nv: Tag shadow S2 entries with guest's leaf S2 level
KVM: arm64: nv: Handle FEAT_TTL hinted TLB operations
KVM: arm64: nv: Handle TLBI IPAS2E1{,IS} operations
KVM: arm64: nv: Handle TLBI ALLE1{,IS} operations
KVM: arm64: nv: Handle TLBI VMALLS12E1{,IS} operations
KVM: arm64: nv: Handle TLB invalidation targeting L2 stage-1
KVM: arm64: nv: Handle EL2 Stage-1 TLB invalidation
KVM: arm64: nv: Add Stage-1 EL2 invalidation primitives
KVM: arm64: nv: Unmap/flush shadow stage 2 page tables
KVM: arm64: nv: Handle shadow stage 2 page faults
KVM: arm64: nv: Implement nested Stage-2 page table walk logic
KVM: arm64: nv: Support multiple nested Stage-2 mmu structures
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
There are 2 functions to calculate traps via HCR_EL2:
* kvm_init_sysreg() called via KVM_RUN (before the 1st run or when
the pid changes)
* vcpu_reset_hcr() called via KVM_ARM_VCPU_INIT
To unify these 2 and to support traps that are dependent on the
ID register configuration, move the code from vcpu_reset_hcr()
to sys_regs.c and call it via kvm_init_sysreg().
We still have to keep the non-FWB handling stuff in vcpu_reset_hcr().
Also the initialization with HCR_GUEST_FLAGS is kept there but guarded
by !vcpu_has_run_once() to ensure that previous calculated values
don't get overwritten.
While at it rename kvm_init_sysreg() to kvm_calculate_traps() to
better reflect what it's doing.
Signed-off-by: Sebastian Ott <sebott@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20240619174036.483943-7-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Add Stage-2 mmu data structures for virtual EL2 and for nested guests.
We don't yet populate shadow Stage-2 page tables, but we now have a
framework for getting to a shadow Stage-2 pgd.
We allocate twice the number of vcpus as Stage-2 mmu structures because
that's sufficient for each vcpu running two translation regimes without
having to flush the Stage-2 page tables.
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240614144552.2773592-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Introduce vcpu->wants_to_run to indicate when a vCPU is in its core run
loop, i.e. when the vCPU is running the KVM_RUN ioctl and immediate_exit
was not set.
Replace all references to vcpu->run->immediate_exit with
!vcpu->wants_to_run to avoid TOCTOU races with userspace. For example, a
malicious userspace could invoked KVM_RUN with immediate_exit=true and
then after KVM reads it to set wants_to_run=false, flip it to false.
This would result in the vCPU running in KVM_RUN with
wants_to_run=false. This wouldn't cause any real bugs today but is a
dangerous landmine.
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240503181734.1467938-2-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add an early_params to control WFI and WFE trapping. This is to
control the degree guests can wait for interrupts on their own without
being trapped by KVM. Options for each param are trap and notrap. trap
enables the trap. notrap disables the trap. Note that when enabled,
traps are allowed but not guaranteed by the CPU architecture. Absent
an explicitly set policy, default to current behavior: disabling the
trap if only a single task is running and enabling otherwise.
Signed-off-by: Colton Lewis <coltonlewis@google.com>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Link: https://lore.kernel.org/r/20240523174056.1565133-1-coltonlewis@google.com
[ oliver: rework kvm_vcpu_should_clear_tw*() for readability ]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Now that we have introduced finalize_init_hyp_mode(), lets
consolidate the initializing of the host_data fpsimd_state and
sve state.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240603122852.3923848-8-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Protected mode needs to maintain (save/restore) the host's sve
state, rather than relying on the host kernel to do that. This is
to avoid leaking information to the host about guests and the
type of operations they are performing.
As a first step towards that, allocate memory mapped at hyp, per
cpu, for the host sve state. The following patch will use this
memory to save/restore the host state.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20240603122852.3923848-6-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/mpidr-reset:
: .
: Fixes for CLIDR_EL1 and MPIDR_EL1 being accidentally mutable across
: a vcpu reset, courtesy of Oliver. From the cover letter:
:
: "For VM-wide feature ID registers we ensure they get initialized once for
: the lifetime of a VM. On the other hand, vCPU-local feature ID registers
: get re-initialized on every vCPU reset, potentially clobbering the
: values userspace set up.
:
: MPIDR_EL1 and CLIDR_EL1 are the only registers in this space that we
: allow userspace to modify for now. Clobbering the value of MPIDR_EL1 has
: some disastrous side effects as the compressed index used by the
: MPIDR-to-vCPU lookup table assumes MPIDR_EL1 is immutable after KVM_RUN.
:
: Series + reproducer test case to address the problem of KVM wiping out
: userspace changes to these registers. Note that there are still some
: differences between VM and vCPU scoped feature ID registers from the
: perspective of userspace. We do not allow the value of VM-scope
: registers to change after KVM_RUN, but vCPU registers remain mutable."
: .
KVM: selftests: arm64: Test vCPU-scoped feature ID registers
KVM: selftests: arm64: Test that feature ID regs survive a reset
KVM: selftests: arm64: Store expected register value in set_id_regs
KVM: selftests: arm64: Rename helper in set_id_regs to imply VM scope
KVM: arm64: Only reset vCPU-scoped feature ID regs once
KVM: arm64: Reset VM feature ID regs from kvm_reset_sys_regs()
KVM: arm64: Rename is_id_reg() to imply VM scope
Signed-off-by: Marc Zyngier <maz@kernel.org>
The general expecation with feature ID registers is that they're 'reset'
exactly once by KVM for the lifetime of a vCPU/VM, such that any
userspace changes to the CPU features / identity are honored after a
vCPU gets reset (e.g. PSCI_ON).
KVM handles what it calls VM-scoped feature ID registers correctly, but
feature ID registers local to a vCPU (CLIDR_EL1, MPIDR_EL1) get wiped
after every reset. What's especially concerning is that a
potentially-changing MPIDR_EL1 breaks MPIDR compression for indexing
mpidr_data, as the mask of useful bits to build the index could change.
This is absolutely no good. Avoid resetting vCPU feature ID registers
more than once.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240502233529.1958459-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/misc-6.10:
: .
: Misc fixes and updates targeting 6.10
:
: - Improve boot-time diagnostics when the sysreg tables
: are not correctly sorted
:
: - Allow FFA_MSG_SEND_DIRECT_REQ in the FFA proxy
:
: - Fix duplicate XNX field in the ID_AA64MMFR1_EL1
: writeable mask
:
: - Allocate PPIs and SGIs outside of the vcpu structure, allowing
: for smaller EL2 mapping and some flexibility in implementing
: more or less than 32 private IRQs.
:
: - Use bitmap_gather() instead of its open-coded equivalent
:
: - Make protected mode use hVHE if available
:
: - Purge stale mpidr_data if a vcpu is created after the MPIDR
: map has been created
: .
KVM: arm64: Destroy mpidr_data for 'late' vCPU creation
KVM: arm64: Use hVHE in pKVM by default on CPUs with VHE support
KVM: arm64: Fix hvhe/nvhe early alias parsing
KVM: arm64: Convert kvm_mpidr_index() to bitmap_gather()
KVM: arm64: vgic: Allocate private interrupts on demand
KVM: arm64: Remove duplicated AA64MMFR1_EL1 XNX
KVM: arm64: Remove FFA_MSG_SEND_DIRECT_REQ from the denylist
KVM: arm64: Improve out-of-order sysreg table diagnostics
Signed-off-by: Marc Zyngier <maz@kernel.org>
A particularly annoying userspace could create a vCPU after KVM has
computed mpidr_data for the VM, either by racing against VGIC
initialization or having a userspace irqchip.
In any case, this means mpidr_data no longer fully describes the VM, and
attempts to find the new vCPU with kvm_mpidr_to_vcpu() will fail. The
fix is to discard mpidr_data altogether, as it is only a performance
optimization and not required for correctness. In all likelihood KVM
will recompute the mappings when KVM_RUN is called on the new vCPU.
Note that reads of mpidr_data are not guarded by a lock; promote to RCU
to cope with the possibility of mpidr_data being invalidated at runtime.
Fixes: 54a8006d0b ("KVM: arm64: Fast-track kvm_mpidr_to_vcpu() when mpidr_data is available")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240508071952.2035422-1-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/pkvm-6.10: (25 commits)
: .
: At last, a bunch of pKVM patches, courtesy of Fuad Tabba.
: From the cover letter:
:
: "This series is a bit of a bombay-mix of patches we've been
: carrying. There's no one overarching theme, but they do improve
: the code by fixing existing bugs in pKVM, refactoring code to
: make it more readable and easier to re-use for pKVM, or adding
: functionality to the existing pKVM code upstream."
: .
KVM: arm64: Force injection of a data abort on NISV MMIO exit
KVM: arm64: Restrict supported capabilities for protected VMs
KVM: arm64: Refactor setting the return value in kvm_vm_ioctl_enable_cap()
KVM: arm64: Document the KVM/arm64-specific calls in hypercalls.rst
KVM: arm64: Rename firmware pseudo-register documentation file
KVM: arm64: Reformat/beautify PTP hypercall documentation
KVM: arm64: Clarify rationale for ZCR_EL1 value restored on guest exit
KVM: arm64: Introduce and use predicates that check for protected VMs
KVM: arm64: Add is_pkvm_initialized() helper
KVM: arm64: Simplify vgic-v3 hypercalls
KVM: arm64: Move setting the page as dirty out of the critical section
KVM: arm64: Change kvm_handle_mmio_return() return polarity
KVM: arm64: Fix comment for __pkvm_vcpu_init_traps()
KVM: arm64: Prevent kmemleak from accessing .hyp.data
KVM: arm64: Do not map the host fpsimd state to hyp in pKVM
KVM: arm64: Rename __tlb_switch_to_{guest,host}() in VHE
KVM: arm64: Support TLB invalidation in guest context
KVM: arm64: Avoid BBM when changing only s/w bits in Stage-2 PTE
KVM: arm64: Check for PTE validity when checking for executable/cacheable
KVM: arm64: Avoid BUG-ing from the host abort path
...
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/nv-eret-pauth:
: .
: Add NV support for the ERETAA/ERETAB instructions. From the cover letter:
:
: "Although the current upstream NV support has *some* support for
: correctly emulating ERET, that support is only partial as it doesn't
: support the ERETAA and ERETAB variants.
:
: Supporting these instructions was cast aside for a long time as it
: involves implementing some form of PAuth emulation, something I wasn't
: overly keen on. But I have reached a point where enough of the
: infrastructure is there that it actually makes sense. So here it is!"
: .
KVM: arm64: nv: Work around lack of pauth support in old toolchains
KVM: arm64: Drop trapping of PAuth instructions/keys
KVM: arm64: nv: Advertise support for PAuth
KVM: arm64: nv: Handle ERETA[AB] instructions
KVM: arm64: nv: Add emulation for ERETAx instructions
KVM: arm64: nv: Add kvm_has_pauth() helper
KVM: arm64: nv: Reinject PAC exceptions caused by HCR_EL2.API==0
KVM: arm64: nv: Handle HCR_EL2.{API,APK} independently
KVM: arm64: nv: Honor HFGITR_EL2.ERET being set
KVM: arm64: nv: Fast-track 'InHost' exception returns
KVM: arm64: nv: Add trap forwarding for ERET and SMC
KVM: arm64: nv: Configure HCR_EL2 for FEAT_NV2
KVM: arm64: nv: Drop VCPU_HYP_CONTEXT flag
KVM: arm64: Constraint PAuth support to consistent implementations
KVM: arm64: Add helpers for ESR_ELx_ERET_ISS_ERET*
KVM: arm64: Harden __ctxt_sys_reg() against out-of-range values
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/host_data:
: .
: Rationalise the host-specific data to live as part of the per-CPU state.
:
: From the cover letter:
:
: "It appears that over the years, we have accumulated a lot of cruft in
: the kvm_vcpu_arch structure. Part of the gunk is data that is strictly
: host CPU specific, and this result in two main problems:
:
: - the structure itself is stupidly large, over 8kB. With the
: arch-agnostic kvm_vcpu, we're above 10kB, which is insane. This has
: some ripple effects, as we need physically contiguous allocation to
: be able to map it at EL2 for !VHE. There is more to it though, as
: some data structures, although per-vcpu, could be allocated
: separately.
:
: - We lose track of the life-cycle of this data, because we're
: guaranteed that it will be around forever and we start relying on
: wrong assumptions. This is becoming a maintenance burden.
:
: This series rectifies some of these things, starting with the two main
: offenders: debug and FP, a lot of which gets pushed out to the per-CPU
: host structure. Indeed, their lifetime really isn't that of the vcpu,
: but tied to the physical CPU the vpcu runs on.
:
: This results in a small reduction of the vcpu size, but mainly a much
: clearer understanding of the life-cycle of these structures."
: .
KVM: arm64: Move management of __hyp_running_vcpu to load/put on VHE
KVM: arm64: Exclude FP ownership from kvm_vcpu_arch
KVM: arm64: Exclude host_fpsimd_state pointer from kvm_vcpu_arch
KVM: arm64: Exclude mdcr_el2_host from kvm_vcpu_arch
KVM: arm64: Exclude host_debug_data from vcpu_arch
KVM: arm64: Add accessor for per-CPU state
Signed-off-by: Marc Zyngier <maz@kernel.org>
For practical reasons as well as security related ones, not all
capabilities are supported for protected VMs in pKVM.
Add a function that restricts the capabilities for protected VMs.
This behaves as an allow-list to ensure that future capabilities
are checked for compatibility and security before being allowed
for protected VMs.
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-30-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Initialize r = -EINVAL to get rid of the error-path
initializations in kvm_vm_ioctl_enable_cap().
No functional change intended.
Suggested-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-29-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Consolidate the GICv3 VMCR accessor hypercalls into the APR save/restore
hypercalls so that all of the EL2 GICv3 state is covered by a single pair
of hypercalls.
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-17-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Most exit handlers return <= 0 to indicate that the host needs to
handle the exit. Make kvm_handle_mmio_return() consistent with
the exit handlers in handle_exit(). This makes the code easier to
reason about, and makes it easier to add other handlers in future
patches.
No functional change intended.
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-15-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
We currently insist on disabling PAuth on vcpu_load(), and get to
enable it on first guest use of an instruction or a key (ignoring
the NV case for now).
It isn't clear at all what this is trying to achieve: guests tend
to use PAuth when available, and nothing forces you to expose it
to the guest if you don't want to. This also isn't totally free:
we take a full GPR save/restore between host and guest, only to
write ten 64bit registers. The "value proposition" escapes me.
So let's forget this stuff and enable PAuth eagerly if exposed to
the guest. This results in much simpler code. Performance wise,
that's not bad either (tested on M2 Pro running a fully automated
Debian installer as the workload):
- On a non-NV guest, I can see reduction of 0.24% in the number
of cycles (measured with perf over 10 consecutive runs)
- On a NV guest (L2), I see a 2% reduction in wall-clock time
(measured with 'time', as M2 doesn't have a PMUv3 and NV
doesn't support it either)
So overall, a much reduced complexity and a (small) performance
improvement.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-16-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
PAuth comes it two parts: address authentication, and generic
authentication. So far, KVM mandates that both are implemented.
PAuth also comes in three flavours: Q5, Q3, and IMPDEF. Only one
can be implemented for any of address and generic authentication.
Crucially, the architecture doesn't mandate that address and generic
authentication implement the *same* flavour. This would make
implementing ERETAx very difficult for NV, something we are not
terribly keen on.
So only allow PAuth support for KVM on systems that are not totally
insane. Which is so far 100% of the known HW.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-4-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
In retrospect, it is fairly obvious that the FP state ownership
is only meaningful for a given CPU, and that locating this
information in the vcpu was just a mistake.
Move the ownership tracking into the host data structure, and
rename it from fp_state to fp_owner, which is a better description
(name suggested by Mark Brown).
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
In order to facilitate the introduction of new per-CPU state,
add a new host_data_ptr() helped that hides some of the per-CPU
verbosity, and make it easier to move that state around in the
future.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
We are not very consistent when it comes to displaying which mode
we're in (VHE, {n,h}VHE, protected or not). For example, booting
in protected mode with hVHE results in:
[ 0.969545] kvm [1]: Protected nVHE mode initialized successfully
which is mildly amusing considering that the machine is VHE only.
We already cleaned this up a bit with commit 1f3ca7023f ("KVM:
arm64: print Hyp mode"), but that's still unsatisfactory.
Unify the three strings into one and use a mess of conditional
statements to sort it out (yes, it's a slow day).
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240321173706.3280796-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/vm-configuration: (29 commits)
: VM configuration enforcement, courtesy of Marc Zyngier
:
: Userspace has gained the ability to control the features visible
: through the ID registers, yet KVM didn't take this into account as the
: effective feature set when determing trap / emulation behavior. This
: series adds:
:
: - Mechanism for testing the presence of a particular CPU feature in the
: guest's ID registers
:
: - Infrastructure for computing the effective value of VNCR-backed
: registers, taking into account the RES0 / RES1 bits for a particular
: VM configuration
:
: - Implementation of 'fine-grained UNDEF' controls that shadow the FGT
: register definitions.
KVM: arm64: Don't initialize idreg debugfs w/ preemption disabled
KVM: arm64: Fail the idreg iterator if idregs aren't initialized
KVM: arm64: Make build-time check of RES0/RES1 bits optional
KVM: arm64: Add debugfs file for guest's ID registers
KVM: arm64: Snapshot all non-zero RES0/RES1 sysreg fields for later checking
KVM: arm64: Make FEAT_MOPS UNDEF if not advertised to the guest
KVM: arm64: Make AMU sysreg UNDEF if FEAT_AMU is not advertised to the guest
KVM: arm64: Make PIR{,E0}_EL1 UNDEF if S1PIE is not advertised to the guest
KVM: arm64: Make TLBI OS/Range UNDEF if not advertised to the guest
KVM: arm64: Streamline save/restore of HFG[RW]TR_EL2
KVM: arm64: Move existing feature disabling over to FGU infrastructure
KVM: arm64: Propagate and handle Fine-Grained UNDEF bits
KVM: arm64: Add Fine-Grained UNDEF tracking information
KVM: arm64: Rename __check_nv_sr_forward() to triage_sysreg_trap()
KVM: arm64: Use the xarray as the primary sysreg/sysinsn walker
KVM: arm64: Register AArch64 system register entries with the sysreg xarray
KVM: arm64: Always populate the trap configuration xarray
KVM: arm64: nv: Move system instructions to their own sys_reg_desc array
KVM: arm64: Drop the requirement for XARRAY_MULTI
KVM: arm64: nv: Turn encoding ranges into discrete XArray stores
...
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Testing KVM with DEBUG_ATOMIC_SLEEP enabled doesn't get far before hitting the
first splat:
BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1578
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 13062, name: vgic_lpi_stress
preempt_count: 1, expected: 0
2 locks held by vgic_lpi_stress/13062:
#0: ffff080084553240 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0xc0/0x13f0
#1: ffff800080485f08 (&kvm->arch.config_lock){+.+.}-{3:3}, at: kvm_arch_vcpu_ioctl+0xd60/0x1788
CPU: 19 PID: 13062 Comm: vgic_lpi_stress Tainted: G W O 6.8.0-dbg-DEV #1
Call trace:
dump_backtrace+0xf8/0x148
show_stack+0x20/0x38
dump_stack_lvl+0xb4/0xf8
dump_stack+0x18/0x40
__might_resched+0x248/0x2a0
__might_sleep+0x50/0x88
down_write+0x30/0x150
start_creating+0x90/0x1a0
__debugfs_create_file+0x5c/0x1b0
debugfs_create_file+0x34/0x48
kvm_reset_sys_regs+0x120/0x1e8
kvm_reset_vcpu+0x148/0x270
kvm_arch_vcpu_ioctl+0xddc/0x1788
kvm_vcpu_ioctl+0xb6c/0x13f0
__arm64_sys_ioctl+0x98/0xd8
invoke_syscall+0x48/0x108
el0_svc_common+0xb4/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x54/0x128
el0t_64_sync_handler+0x68/0xc0
el0t_64_sync+0x1a8/0x1b0
kvm_reset_vcpu() disables preemption as it needs to unload vCPU state
from the CPU to twiddle with it, which subsequently explodes when
taking the parent inode's rwsem while creating the idreg debugfs file.
Fix it by moving the initialization to kvm_arch_create_vm_debugfs().
Fixes: 891766581d ("KVM: arm64: Add debugfs file for guest's ID registers")
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240227094115.1723330-3-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
We already trap a bunch of existing features for the purpose of
disabling them (MAIR2, POR, ACCDATA, SME...).
Let's move them over to our brand new FGU infrastructure.
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-20-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
VNCR-backed "registers" are actually only memory. Which means that
there is zero control over what the guest can write, and that it
is the hypervisor's job to actually sanitise the content of the
backing store. Yeah, this is fun.
In order to preserve some form of sanity, add a repainting mechanism
that makes use of a per-VM set of RES0/RES1 masks, one pair per VNCR
register. These masks get applied on access to the backing store via
__vcpu_sys_reg(), ensuring that the state that is consumed by KVM is
correct.
So far, nothing populates these masks, but stay tuned.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20240214131827.2856277-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Print which of the hyp modes is being used (hVHE, nVHE).
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Mark Brown <broonie@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240209103719.3813599-1-joey.gouly@arm.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
- Use memdup_array_user() to harden against overflow.
- Unconditionally advertise KVM_CAP_DEVICE_CTRL for all architectures.
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Merge tag 'kvm-x86-generic-6.8' of https://github.com/kvm-x86/linux into HEAD
Common KVM changes for 6.8:
- Use memdup_array_user() to harden against overflow.
- Unconditionally advertise KVM_CAP_DEVICE_CTRL for all architectures.
- LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB
base granule sizes. Branch shared with the arm64 tree.
- Large Fine-Grained Trap rework, bringing some sanity to the
feature, although there is more to come. This comes with
a prefix branch shared with the arm64 tree.
- Some additional Nested Virtualization groundwork, mostly
introducing the NV2 VNCR support and retargetting the NV
support to that version of the architecture.
- A small set of vgic fixes and associated cleanups.
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Merge tag 'kvmarm-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for Linux 6.8
- LPA2 support, adding 52bit IPA/PA capability for 4kB and 16kB
base granule sizes. Branch shared with the arm64 tree.
- Large Fine-Grained Trap rework, bringing some sanity to the
feature, although there is more to come. This comes with
a prefix branch shared with the arm64 tree.
- Some additional Nested Virtualization groundwork, mostly
introducing the NV2 VNCR support and retargetting the NV
support to that version of the architecture.
- A small set of vgic fixes and associated cleanups.
* kvm-arm64/nv-6.8-prefix:
: .
: Nested Virtualization support update, focussing on the
: NV2 support (VNCR mapping and such).
: .
KVM: arm64: nv: Handle virtual EL2 registers in vcpu_read/write_sys_reg()
KVM: arm64: nv: Map VNCR-capable registers to a separate page
KVM: arm64: nv: Add EL2_REG_VNCR()/EL2_REG_REDIR() sysreg helpers
KVM: arm64: Introduce a bad_trap() primitive for unexpected trap handling
KVM: arm64: nv: Add include containing the VNCR_EL2 offsets
KVM: arm64: nv: Add non-VHE-EL2->EL1 translation helpers
KVM: arm64: nv: Drop EL12 register traps that are redirected to VNCR
KVM: arm64: nv: Compute NV view of idregs as a one-off
KVM: arm64: nv: Hoist vcpu_has_nv() into is_hyp_ctxt()
arm64: cpufeatures: Restrict NV support to FEAT_NV2
Signed-off-by: Marc Zyngier <maz@kernel.org>
Now that we have a full copy of the idregs for each VM, there is
no point in repainting the sysregs on each access. Instead, we
can simply perform the transmation as a one-off and be done
with it.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
When failing to create a vcpu because (for example) it has a
duplicate vcpu_id, we destroy the vcpu. Amusingly, this leaves
the redistributor registered with the KVM_MMIO bus.
This is no good, and we should properly clean the mess. Force
a teardown of the vgic vcpu interface, including the RD device
before returning to the caller.
Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231207151201.3028710-4-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
KVM_CAP_DEVICE_CTRL allows userspace to check if the kvm_device
framework (e.g. KVM_CREATE_DEVICE) is supported by KVM. Move
KVM_CAP_DEVICE_CTRL to the generic check for the two reasons:
1) it already supports arch agnostic usages (i.e. KVM_DEV_TYPE_VFIO).
For example, userspace VFIO implementation may needs to create
KVM_DEV_TYPE_VFIO on x86, riscv, or arm etc. It is simpler to have it
checked at the generic code than at each arch's code.
2) KVM_CREATE_DEVICE has been added to the generic code.
Link: https://lore.kernel.org/all/20221215115207.14784-1-wei.w.wang@intel.com
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Acked-by: Anup Patel <anup@brainfault.org> (riscv)
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Link: https://lore.kernel.org/r/20230315101606.10636-1-wei.w.wang@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Implement a simple policy whereby if the HW supports FEAT_LPA2 for the
page size we are using, always use LPA2-style page-tables for stage 2
and hyp stage 1 (assuming an nvhe hyp), regardless of the VMM-requested
IPA size or HW-implemented PA size. When in use we can now support up to
52-bit IPA and PA sizes.
We use the previously created cpu feature to track whether LPA2 is
supported for deciding whether to use the LPA2 or classic pte format.
Note that FEAT_LPA2 brings support for bigger block mappings (512GB with
4KB, 64GB with 16KB). We explicitly don't enable these in the library
because stage2_apply_range() works on batch sizes of the largest used
block mapping, and increasing the size of the batch would lead to soft
lockups. See commit 5994bc9e05 ("KVM: arm64: Limit
stage2_apply_range() batch size to largest block").
With the addition of LPA2 support in the hypervisor, the PA size
supported by the HW must be capped with a runtime decision, rather than
simply using a compile-time decision based on PA_BITS. For example, on a
system that advertises 52 bit PA but does not support FEAT_LPA2, A 4KB
or 16KB kernel compiled with LPA2 support must still limit the PA size
to 48 bits.
Therefore, move the insertion of the PS field into TCR_EL2 out of
__kvm_hyp_init assembly code and instead do it in cpu_prepare_hyp_mode()
where the rest of TCR_EL2 is prepared. This allows us to figure out PS
with kvm_get_parange(), which has the appropriate logic to ensure the
above requirement. (and the PS field of VTCR_EL2 is already populated
this way).
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231127111737.1897081-8-ryan.roberts@arm.com
* Generalized infrastructure for 'writable' ID registers, effectively
allowing userspace to opt-out of certain vCPU features for its guest
* Optimization for vSGI injection, opportunistically compressing MPIDR
to vCPU mapping into a table
* Improvements to KVM's PMU emulation, allowing userspace to select
the number of PMCs available to a VM
* Guest support for memory operation instructions (FEAT_MOPS)
* Cleanups to handling feature flags in KVM_ARM_VCPU_INIT, squashing
bugs and getting rid of useless code
* Changes to the way the SMCCC filter is constructed, avoiding wasted
memory allocations when not in use
* Load the stage-2 MMU context at vcpu_load() for VHE systems, reducing
the overhead of errata mitigations
* Miscellaneous kernel and selftest fixes
LoongArch:
* New architecture. The hardware uses the same model as x86, s390
and RISC-V, where guest/host mode is orthogonal to supervisor/user
mode. The virtualization extensions are very similar to MIPS,
therefore the code also has some similarities but it's been cleaned
up to avoid some of the historical bogosities that are found in
arch/mips. The kernel emulates MMU, timer and CSR accesses, while
interrupt controllers are only emulated in userspace, at least for
now.
RISC-V:
* Support for the Smstateen and Zicond extensions
* Support for virtualizing senvcfg
* Support for virtualized SBI debug console (DBCN)
S390:
* Nested page table management can be monitored through tracepoints
and statistics
x86:
* Fix incorrect handling of VMX posted interrupt descriptor in KVM_SET_LAPIC,
which could result in a dropped timer IRQ
* Avoid WARN on systems with Intel IPI virtualization
* Add CONFIG_KVM_MAX_NR_VCPUS, to allow supporting up to 4096 vCPUs without
forcing more common use cases to eat the extra memory overhead.
* Add virtualization support for AMD SRSO mitigation (IBPB_BRTYPE and
SBPB, aka Selective Branch Predictor Barrier).
* Fix a bug where restoring a vCPU snapshot that was taken within 1 second of
creating the original vCPU would cause KVM to try to synchronize the vCPU's
TSC and thus clobber the correct TSC being set by userspace.
* Compute guest wall clock using a single TSC read to avoid generating an
inaccurate time, e.g. if the vCPU is preempted between multiple TSC reads.
* "Virtualize" HWCR.TscFreqSel to make Linux guests happy, which complain
about a "Firmware Bug" if the bit isn't set for select F/M/S combos.
Likewise "virtualize" (ignore) MSR_AMD64_TW_CFG to appease Windows Server
2022.
* Don't apply side effects to Hyper-V's synthetic timer on writes from
userspace to fix an issue where the auto-enable behavior can trigger
spurious interrupts, i.e. do auto-enabling only for guest writes.
* Remove an unnecessary kick of all vCPUs when synchronizing the dirty log
without PML enabled.
* Advertise "support" for non-serializing FS/GS base MSR writes as appropriate.
* Harden the fast page fault path to guard against encountering an invalid
root when walking SPTEs.
* Omit "struct kvm_vcpu_xen" entirely when CONFIG_KVM_XEN=n.
* Use the fast path directly from the timer callback when delivering Xen
timer events, instead of waiting for the next iteration of the run loop.
This was not done so far because previously proposed code had races,
but now care is taken to stop the hrtimer at critical points such as
restarting the timer or saving the timer information for userspace.
* Follow the lead of upstream Xen and ignore the VCPU_SSHOTTMR_future flag.
* Optimize injection of PMU interrupts that are simultaneous with NMIs.
* Usual handful of fixes for typos and other warts.
x86 - MTRR/PAT fixes and optimizations:
* Clean up code that deals with honoring guest MTRRs when the VM has
non-coherent DMA and host MTRRs are ignored, i.e. EPT is enabled.
* Zap EPT entries when non-coherent DMA assignment stops/start to prevent
using stale entries with the wrong memtype.
* Don't ignore guest PAT for CR0.CD=1 && KVM_X86_QUIRK_CD_NW_CLEARED=y.
This was done as a workaround for virtual machine BIOSes that did not
bother to clear CR0.CD (because ancient KVM/QEMU did not bother to
set it, in turn), and there's zero reason to extend the quirk to
also ignore guest PAT.
x86 - SEV fixes:
* Report KVM_EXIT_SHUTDOWN instead of EINVAL if KVM intercepts SHUTDOWN while
running an SEV-ES guest.
* Clean up the recognition of emulation failures on SEV guests, when KVM would
like to "skip" the instruction but it had already been partially emulated.
This makes it possible to drop a hack that second guessed the (insufficient)
information provided by the emulator, and just do the right thing.
Documentation:
* Various updates and fixes, mostly for x86
* MTRR and PAT fixes and optimizations:
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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:
- Generalized infrastructure for 'writable' ID registers, effectively
allowing userspace to opt-out of certain vCPU features for its
guest
- Optimization for vSGI injection, opportunistically compressing
MPIDR to vCPU mapping into a table
- Improvements to KVM's PMU emulation, allowing userspace to select
the number of PMCs available to a VM
- Guest support for memory operation instructions (FEAT_MOPS)
- Cleanups to handling feature flags in KVM_ARM_VCPU_INIT, squashing
bugs and getting rid of useless code
- Changes to the way the SMCCC filter is constructed, avoiding wasted
memory allocations when not in use
- Load the stage-2 MMU context at vcpu_load() for VHE systems,
reducing the overhead of errata mitigations
- Miscellaneous kernel and selftest fixes
LoongArch:
- New architecture for kvm.
The hardware uses the same model as x86, s390 and RISC-V, where
guest/host mode is orthogonal to supervisor/user mode. The
virtualization extensions are very similar to MIPS, therefore the
code also has some similarities but it's been cleaned up to avoid
some of the historical bogosities that are found in arch/mips. The
kernel emulates MMU, timer and CSR accesses, while interrupt
controllers are only emulated in userspace, at least for now.
RISC-V:
- Support for the Smstateen and Zicond extensions
- Support for virtualizing senvcfg
- Support for virtualized SBI debug console (DBCN)
S390:
- Nested page table management can be monitored through tracepoints
and statistics
x86:
- Fix incorrect handling of VMX posted interrupt descriptor in
KVM_SET_LAPIC, which could result in a dropped timer IRQ
- Avoid WARN on systems with Intel IPI virtualization
- Add CONFIG_KVM_MAX_NR_VCPUS, to allow supporting up to 4096 vCPUs
without forcing more common use cases to eat the extra memory
overhead.
- Add virtualization support for AMD SRSO mitigation (IBPB_BRTYPE and
SBPB, aka Selective Branch Predictor Barrier).
- Fix a bug where restoring a vCPU snapshot that was taken within 1
second of creating the original vCPU would cause KVM to try to
synchronize the vCPU's TSC and thus clobber the correct TSC being
set by userspace.
- Compute guest wall clock using a single TSC read to avoid
generating an inaccurate time, e.g. if the vCPU is preempted
between multiple TSC reads.
- "Virtualize" HWCR.TscFreqSel to make Linux guests happy, which
complain about a "Firmware Bug" if the bit isn't set for select
F/M/S combos. Likewise "virtualize" (ignore) MSR_AMD64_TW_CFG to
appease Windows Server 2022.
- Don't apply side effects to Hyper-V's synthetic timer on writes
from userspace to fix an issue where the auto-enable behavior can
trigger spurious interrupts, i.e. do auto-enabling only for guest
writes.
- Remove an unnecessary kick of all vCPUs when synchronizing the
dirty log without PML enabled.
- Advertise "support" for non-serializing FS/GS base MSR writes as
appropriate.
- Harden the fast page fault path to guard against encountering an
invalid root when walking SPTEs.
- Omit "struct kvm_vcpu_xen" entirely when CONFIG_KVM_XEN=n.
- Use the fast path directly from the timer callback when delivering
Xen timer events, instead of waiting for the next iteration of the
run loop. This was not done so far because previously proposed code
had races, but now care is taken to stop the hrtimer at critical
points such as restarting the timer or saving the timer information
for userspace.
- Follow the lead of upstream Xen and ignore the VCPU_SSHOTTMR_future
flag.
- Optimize injection of PMU interrupts that are simultaneous with
NMIs.
- Usual handful of fixes for typos and other warts.
x86 - MTRR/PAT fixes and optimizations:
- Clean up code that deals with honoring guest MTRRs when the VM has
non-coherent DMA and host MTRRs are ignored, i.e. EPT is enabled.
- Zap EPT entries when non-coherent DMA assignment stops/start to
prevent using stale entries with the wrong memtype.
- Don't ignore guest PAT for CR0.CD=1 && KVM_X86_QUIRK_CD_NW_CLEARED=y
This was done as a workaround for virtual machine BIOSes that did
not bother to clear CR0.CD (because ancient KVM/QEMU did not bother
to set it, in turn), and there's zero reason to extend the quirk to
also ignore guest PAT.
x86 - SEV fixes:
- Report KVM_EXIT_SHUTDOWN instead of EINVAL if KVM intercepts
SHUTDOWN while running an SEV-ES guest.
- Clean up the recognition of emulation failures on SEV guests, when
KVM would like to "skip" the instruction but it had already been
partially emulated. This makes it possible to drop a hack that
second guessed the (insufficient) information provided by the
emulator, and just do the right thing.
Documentation:
- Various updates and fixes, mostly for x86
- MTRR and PAT fixes and optimizations"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (164 commits)
KVM: selftests: Avoid using forced target for generating arm64 headers
tools headers arm64: Fix references to top srcdir in Makefile
KVM: arm64: Add tracepoint for MMIO accesses where ISV==0
KVM: arm64: selftest: Perform ISB before reading PAR_EL1
KVM: arm64: selftest: Add the missing .guest_prepare()
KVM: arm64: Always invalidate TLB for stage-2 permission faults
KVM: x86: Service NMI requests after PMI requests in VM-Enter path
KVM: arm64: Handle AArch32 SPSR_{irq,abt,und,fiq} as RAZ/WI
KVM: arm64: Do not let a L1 hypervisor access the *32_EL2 sysregs
KVM: arm64: Refine _EL2 system register list that require trap reinjection
arm64: Add missing _EL2 encodings
arm64: Add missing _EL12 encodings
KVM: selftests: aarch64: vPMU test for validating user accesses
KVM: selftests: aarch64: vPMU register test for unimplemented counters
KVM: selftests: aarch64: vPMU register test for implemented counters
KVM: selftests: aarch64: Introduce vpmu_counter_access test
tools: Import arm_pmuv3.h
KVM: arm64: PMU: Allow userspace to limit PMCR_EL0.N for the guest
KVM: arm64: Sanitize PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR} before first run
KVM: arm64: Add {get,set}_user for PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}
...
* kvm-arm64/pmu_pmcr_n:
: User-defined PMC limit, courtesy Raghavendra Rao Ananta
:
: Certain VMMs may want to reserve some PMCs for host use while running a
: KVM guest. This was a bit difficult before, as KVM advertised all
: supported counters to the guest. Userspace can now limit the number of
: advertised PMCs by writing to PMCR_EL0.N, as KVM's sysreg and PMU
: emulation enforce the specified limit for handling guest accesses.
KVM: selftests: aarch64: vPMU test for validating user accesses
KVM: selftests: aarch64: vPMU register test for unimplemented counters
KVM: selftests: aarch64: vPMU register test for implemented counters
KVM: selftests: aarch64: Introduce vpmu_counter_access test
tools: Import arm_pmuv3.h
KVM: arm64: PMU: Allow userspace to limit PMCR_EL0.N for the guest
KVM: arm64: Sanitize PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR} before first run
KVM: arm64: Add {get,set}_user for PM{C,I}NTEN{SET,CLR}, PMOVS{SET,CLR}
KVM: arm64: PMU: Set PMCR_EL0.N for vCPU based on the associated PMU
KVM: arm64: PMU: Add a helper to read a vCPU's PMCR_EL0
KVM: arm64: Select default PMU in KVM_ARM_VCPU_INIT handler
KVM: arm64: PMU: Introduce helpers to set the guest's PMU
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/writable-id-regs:
: Writable ID registers, courtesy of Jing Zhang
:
: This series significantly expands the architectural feature set that
: userspace can manipulate via the ID registers. A new ioctl is defined
: that makes the mutable fields in the ID registers discoverable to
: userspace.
KVM: selftests: Avoid using forced target for generating arm64 headers
tools headers arm64: Fix references to top srcdir in Makefile
KVM: arm64: selftests: Test for setting ID register from usersapce
tools headers arm64: Update sysreg.h with kernel sources
KVM: selftests: Generate sysreg-defs.h and add to include path
perf build: Generate arm64's sysreg-defs.h and add to include path
tools: arm64: Add a Makefile for generating sysreg-defs.h
KVM: arm64: Document vCPU feature selection UAPIs
KVM: arm64: Allow userspace to change ID_AA64ZFR0_EL1
KVM: arm64: Allow userspace to change ID_AA64PFR0_EL1
KVM: arm64: Allow userspace to change ID_AA64MMFR{0-2}_EL1
KVM: arm64: Allow userspace to change ID_AA64ISAR{0-2}_EL1
KVM: arm64: Bump up the default KVM sanitised debug version to v8p8
KVM: arm64: Reject attempts to set invalid debug arch version
KVM: arm64: Advertise selected DebugVer in DBGDIDR.Version
KVM: arm64: Use guest ID register values for the sake of emulation
KVM: arm64: Document KVM_ARM_GET_REG_WRITABLE_MASKS
KVM: arm64: Allow userspace to get the writable masks for feature ID registers
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/sgi-injection:
: vSGI injection improvements + fixes, courtesy Marc Zyngier
:
: Avoid linearly searching for vSGI targets using a compressed MPIDR to
: index a cache. While at it, fix some egregious bugs in KVM's mishandling
: of vcpuid (user-controlled value) and vcpu_idx.
KVM: arm64: Clarify the ordering requirements for vcpu/RD creation
KVM: arm64: vgic-v3: Optimize affinity-based SGI injection
KVM: arm64: Fast-track kvm_mpidr_to_vcpu() when mpidr_data is available
KVM: arm64: Build MPIDR to vcpu index cache at runtime
KVM: arm64: Simplify kvm_vcpu_get_mpidr_aff()
KVM: arm64: Use vcpu_idx for invalidation tracking
KVM: arm64: vgic: Use vcpu_idx for the debug information
KVM: arm64: vgic-v2: Use cpuid from userspace as vcpu_id
KVM: arm64: vgic-v3: Refactor GICv3 SGI generation
KVM: arm64: vgic-its: Treat the collection target address as a vcpu_id
KVM: arm64: vgic: Make kvm_vgic_inject_irq() take a vcpu pointer
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
* kvm-arm64/stage2-vhe-load:
: Setup stage-2 MMU from vcpu_load() for VHE
:
: Unlike nVHE, there is no need to switch the stage-2 MMU around on guest
: entry/exit in VHE mode as the host is running at EL2. Despite this KVM
: reloads the stage-2 on every guest entry, which is needless.
:
: This series moves the setup of the stage-2 MMU context to vcpu_load()
: when running in VHE mode. This is likely to be a win across the board,
: but also allows us to remove an ISB on the guest entry path for systems
: with one of the speculative AT errata.
KVM: arm64: Move VTCR_EL2 into struct s2_mmu
KVM: arm64: Load the stage-2 MMU context in kvm_vcpu_load_vhe()
KVM: arm64: Rename helpers for VHE vCPU load/put
KVM: arm64: Reload stage-2 for VMID change on VHE
KVM: arm64: Restore the stage-2 context in VHE's __tlb_switch_to_host()
KVM: arm64: Don't zero VTTBR in __tlb_switch_to_host()
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
For unimplemented counters, the registers PM{C,I}NTEN{SET,CLR}
and PMOVS{SET,CLR} are expected to have the corresponding bits RAZ.
Hence to ensure correct KVM's PMU emulation, mask out the RES0 bits.
Defer this work to the point that userspace can no longer change the
number of advertised PMCs.
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231020214053.2144305-7-rananta@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Add a helper to read a vCPU's PMCR_EL0, and use it whenever KVM
reads a vCPU's PMCR_EL0.
Currently, the PMCR_EL0 value is tracked per vCPU. The following
patches will make (only) PMCR_EL0.N track per guest. Having the
new helper will be useful to combine the PMCR_EL0.N field
(tracked per guest) and the other fields (tracked per vCPU)
to provide the value of PMCR_EL0.
No functional change intended.
Reviewed-by: Sebastian Ott <sebott@redhat.com>
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231020214053.2144305-4-rananta@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Future changes to KVM's sysreg emulation will rely on having a valid PMU
instance to determine the number of implemented counters (PMCR_EL0.N).
This is earlier than when userspace is expected to modify the vPMU
device attributes, where the default is selected today.
Select the default PMU when handling KVM_ARM_VCPU_INIT such that it is
available in time for sysreg emulation.
Reviewed-by: Sebastian Ott <sebott@redhat.com>
Co-developed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Link: https://lore.kernel.org/r/20231020214053.2144305-3-rananta@google.com
[Oliver: rewrite changelog]
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
The names for the helpers we expose to the 'generic' KVM code are a bit
imprecise; we switch the EL0 + EL1 sysreg context and setup trap
controls that do not need to change for every guest entry/exit. Rename +
shuffle things around a bit in preparation for loading the stage-2 MMU
context on vcpu_load().
Link: https://lore.kernel.org/r/20231018233212.2888027-5-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Naturally, a change to the VMID for an MMU implies a new value for
VTTBR. Reload on VMID change in anticipation of loading stage-2 on
vcpu_load() instead of every guest entry.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231018233212.2888027-4-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Much of the arm64 KVM code uses cpus_have_const_cap() to check for
cpucaps, but this is unnecessary and it would be preferable to use
cpus_have_final_cap().
For historical reasons, cpus_have_const_cap() is more complicated than
it needs to be. Before cpucaps are finalized, it will perform a bitmap
test of the system_cpucaps bitmap, and once cpucaps are finalized it
will use an alternative branch. This used to be necessary to handle some
race conditions in the window between cpucap detection and the
subsequent patching of alternatives and static branches, where different
branches could be out-of-sync with one another (or w.r.t. alternative
sequences). Now that we use alternative branches instead of static
branches, these are all patched atomically w.r.t. one another, and there
are only a handful of cases that need special care in the window between
cpucap detection and alternative patching.
Due to the above, it would be nice to remove cpus_have_const_cap(), and
migrate callers over to alternative_has_cap_*(), cpus_have_final_cap(),
or cpus_have_cap() depending on when their requirements. This will
remove redundant instructions and improve code generation, and will make
it easier to determine how each callsite will behave before, during, and
after alternative patching.
KVM is initialized after cpucaps have been finalized and alternatives
have been patched. Since commit:
d86de40dec ("arm64: cpufeature: upgrade hyp caps to final")
... use of cpus_have_const_cap() in hyp code is automatically converted
to use cpus_have_final_cap():
| static __always_inline bool cpus_have_const_cap(int num)
| {
| if (is_hyp_code())
| return cpus_have_final_cap(num);
| else if (system_capabilities_finalized())
| return __cpus_have_const_cap(num);
| else
| return cpus_have_cap(num);
| }
Thus, converting hyp code to use cpus_have_final_cap() directly will not
result in any functional change.
Non-hyp KVM code is also not executed until cpucaps have been finalized,
and it would be preferable to extent the same treatment to this code and
use cpus_have_final_cap() directly.
This patch converts instances of cpus_have_const_cap() in KVM-only code
over to cpus_have_final_cap(). As all of this code runs after cpucaps
have been finalized, there should be no functional change as a result of
this patch, but the redundant instructions generated by
cpus_have_const_cap() will be removed from the non-hyp KVM code.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
While the Feature ID range is well defined and pretty large, it isn't
inconceivable that the architecture will eventually grow some other
ranges that will need to similarly be described to userspace.
Add a VM ioctl to allow userspace to get writable masks for feature ID
registers in below system register space:
op0 = 3, op1 = {0, 1, 3}, CRn = 0, CRm = {0 - 7}, op2 = {0 - 7}
This is used to support mix-and-match userspace and kernels for writable
ID registers, where userspace may want to know upfront whether it can
actually tweak the contents of an idreg or not.
Add a new capability (KVM_CAP_ARM_SUPPORTED_FEATURE_ID_RANGES) that
returns a bitmap of the valid ranges, which can subsequently be
retrieved, one at a time by setting the index of the set bit as the
range identifier.
Suggested-by: Marc Zyngier <maz@kernel.org>
Suggested-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
If our fancy little table is present when calling kvm_mpidr_to_vcpu(),
use it to recover the corresponding vcpu.
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Tested-by: Joey Gouly <joey.gouly@arm.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230927090911.3355209-10-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
The MPIDR_EL1 register contains a unique value that identifies
the CPU. The only problem with it is that it is stupidly large
(32 bits, once the useless stuff is removed).
Trying to obtain a vcpu from an MPIDR value is a fairly common,
yet costly operation: we iterate over all the vcpus until we
find the correct one. While this is cheap for small VMs, it is
pretty expensive on large ones, specially if you are trying to
get to the one that's at the end of the list...
In order to help with this, it is important to realise that
the MPIDR values are actually structured, and that implementations
tend to use a small number of significant bits in the 32bit space.
We can use this fact to our advantage by computing a small hash
table that uses the "compression" of the significant MPIDR bits
as an index, giving us the vcpu index as a result.
Given that the MPIDR values can be supplied by userspace, and
that an evil VMM could decide to make *all* bits significant,
resulting in a 4G-entry table, we only use this method if the
resulting table fits in a single page. Otherwise, we fallback
to the good old iterative method.
Nothing uses that table just yet, but keep your eyes peeled.
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Tested-by: Joey Gouly <joey.gouly@arm.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230927090911.3355209-9-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
While vcpu_id isn't necessarily a bad choice as an identifier for
the currently running vcpu, it is provided by userspace, and there
is close to no guarantee that it would be unique.
Switch it to vcpu_idx instead, for which we have much stronger
guarantees.
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230927090911.3355209-7-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Passing a vcpu_id to kvm_vgic_inject_irq() is silly for two reasons:
- we often confuse vcpu_id and vcpu_idx
- we eventually have to convert it back to a vcpu
- we can't count
Instead, pass a vcpu pointer, which is unambiguous. A NULL vcpu
is also allowed for interrupts that are not private to a vcpu
(such as SPIs).
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230927090911.3355209-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
The vCPU-scoped feature bitmap was left in place a couple of releases
ago in case the change to VM-scoped vCPU features broke anyone. Nobody
has complained and the interop between VM and vCPU bitmaps is pretty
gross. Throw it out.
Link: https://lore.kernel.org/r/20230920195036.1169791-9-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
It would appear that userspace can select the NV feature flag regardless
of whether the system actually supports the feature. Obviously a nested
guest isn't getting far in this situation; let's reject the flag
instead.
Link: https://lore.kernel.org/r/20230920195036.1169791-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Test for feature support in the ioctl handler rather than
kvm_reset_vcpu(). Continue to uphold our all-or-nothing policy with
address and generic pointer authentication.
Link: https://lore.kernel.org/r/20230920195036.1169791-5-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
To date KVM has relied on kvm_reset_vcpu() failing when the vCPU feature
flags are unsupported by the system. This is a bit messy since
kvm_reset_vcpu() is called at runtime outside of the KVM_ARM_VCPU_INIT
ioctl when it is expected to succeed. Further complicating the matter is
that kvm_reset_vcpu() must tolerate be idemptotent to the config_lock,
as it isn't consistently called with the lock held.
Prepare to move feature compatibility checks out of kvm_reset_vcpu() with
a 'generic' check that compares the user-provided flags with a computed
maximum feature set for the system.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20230920195036.1169791-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
- Add support for TLB range invalidation of Stage-2 page tables,
avoiding unnecessary invalidations. Systems that do not implement
range invalidation still rely on a full invalidation when dealing
with large ranges.
- Add infrastructure for forwarding traps taken from a L2 guest to
the L1 guest, with L0 acting as the dispatcher, another baby step
towards the full nested support.
- Simplify the way we deal with the (long deprecated) 'CPU target',
resulting in a much needed cleanup.
- Fix another set of PMU bugs, both on the guest and host sides,
as we seem to never have any shortage of those...
- Relax the alignment requirements of EL2 VA allocations for
non-stack allocations, as we were otherwise wasting a lot of that
precious VA space.
- The usual set of non-functional cleanups, although I note the lack
of spelling fixes...
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Merge tag 'kvmarm-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 updates for Linux 6.6
- Add support for TLB range invalidation of Stage-2 page tables,
avoiding unnecessary invalidations. Systems that do not implement
range invalidation still rely on a full invalidation when dealing
with large ranges.
- Add infrastructure for forwarding traps taken from a L2 guest to
the L1 guest, with L0 acting as the dispatcher, another baby step
towards the full nested support.
- Simplify the way we deal with the (long deprecated) 'CPU target',
resulting in a much needed cleanup.
- Fix another set of PMU bugs, both on the guest and host sides,
as we seem to never have any shortage of those...
- Relax the alignment requirements of EL2 VA allocations for
non-stack allocations, as we were otherwise wasting a lot of that
precious VA space.
- The usual set of non-functional cleanups, although I note the lack
of spelling fixes...
* kvm-arm64/6.6/misc:
: .
: Misc KVM/arm64 updates for 6.6:
:
: - Don't unnecessary align non-stack allocations in the EL2 VA space
:
: - Drop HCR_VIRT_EXCP_MASK, which was never used...
:
: - Don't use smp_processor_id() in kvm_arch_vcpu_load(),
: but the cpu parameter instead
:
: - Drop redundant call to kvm_set_pfn_accessed() in user_mem_abort()
:
: - Remove prototypes without implementations
: .
KVM: arm64: Remove size-order align in the nVHE hyp private VA range
KVM: arm64: Remove unused declarations
KVM: arm64: Remove redundant kvm_set_pfn_accessed() from user_mem_abort()
KVM: arm64: Drop HCR_VIRT_EXCP_MASK
KVM: arm64: Use the known cpu id instead of smp_processor_id()
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/6.6/pmu-fixes:
: .
: Another set of PMU fixes, coutrtesy of Reiji Watanabe.
: From the cover letter:
:
: "This series fixes a couple of PMUver related handling of
: vPMU support.
:
: On systems where the PMUVer is not uniform across all PEs,
: KVM currently does not advertise PMUv3 to the guest,
: even if userspace successfully runs KVM_ARM_VCPU_INIT with
: KVM_ARM_VCPU_PMU_V3."
:
: Additionally, a fix for an obscure counter oversubscription
: issue happening when the hsot profines the guest's EL0.
: .
KVM: arm64: pmu: Guard PMU emulation definitions with CONFIG_KVM
KVM: arm64: pmu: Resync EL0 state on counter rotation
KVM: arm64: PMU: Don't advertise STALL_SLOT_{FRONTEND,BACKEND}
KVM: arm64: PMU: Don't advertise the STALL_SLOT event
KVM: arm64: PMU: Avoid inappropriate use of host's PMUVer
KVM: arm64: PMU: Disallow vPMU on non-uniform PMUVer
Signed-off-by: Marc Zyngier <maz@kernel.org>
* kvm-arm64/tlbi-range:
: .
: FEAT_TLBIRANGE support, courtesy of Raghavendra Rao Ananta.
: From the cover letter:
:
: "In certain code paths, KVM/ARM currently invalidates the entire VM's
: page-tables instead of just invalidating a necessary range. For example,
: when collapsing a table PTE to a block PTE, instead of iterating over
: each PTE and flushing them, KVM uses 'vmalls12e1is' TLBI operation to
: flush all the entries. This is inefficient since the guest would have
: to refill the TLBs again, even for the addresses that aren't covered
: by the table entry. The performance impact would scale poorly if many
: addresses in the VM is going through this remapping.
:
: For architectures that implement FEAT_TLBIRANGE, KVM can replace such
: inefficient paths by performing the invalidations only on the range of
: addresses that are in scope. This series tries to achieve the same in
: the areas of stage-2 map, unmap and write-protecting the pages."
: .
KVM: arm64: Use TLBI range-based instructions for unmap
KVM: arm64: Invalidate the table entries upon a range
KVM: arm64: Flush only the memslot after write-protect
KVM: arm64: Implement kvm_arch_flush_remote_tlbs_range()
KVM: arm64: Define kvm_tlb_flush_vmid_range()
KVM: arm64: Implement __kvm_tlb_flush_vmid_range()
arm64: tlb: Implement __flush_s2_tlb_range_op()
arm64: tlb: Refactor the core flush algorithm of __flush_tlb_range
KVM: Move kvm_arch_flush_remote_tlbs_memslot() to common code
KVM: Allow range-based TLB invalidation from common code
KVM: Remove CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
KVM: arm64: Use kvm_arch_flush_remote_tlbs()
KVM: Declare kvm_arch_flush_remote_tlbs() globally
KVM: Rename kvm_arch_flush_remote_tlb() to kvm_arch_flush_remote_tlbs()
Signed-off-by: Marc Zyngier <maz@kernel.org>
