Commit Graph

339 Commits

Author SHA1 Message Date
Oliver Upton
02dd33ec88 KVM: arm64: Context switch SCTLR2_ELx when advertised to the guest
Restore SCTLR2_EL1 with the correct value for the given context when
FEAT_SCTLR2 is advertised to the guest.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-13-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-08 11:36:35 -07:00
Oliver Upton
18fbc24707 KVM: arm64: nv: Use guest hypervisor's vSError state
When HCR_EL2.AMO is set, physical SErrors are routed to EL2 and virtual
SError injection is enabled for EL1. Conceptually treating
host-initiated SErrors as 'physical', this means we can delegate control
of the vSError injection context to the guest hypervisor when nesting &&
AMO is set.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-9-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-08 11:36:34 -07:00
Marc Zyngier
1d6fea7663 KVM: arm64: Add helper to identify a nested context
A common idiom in the KVM code is to check if we are currently
dealing with a "nested" context, defined as having NV enabled,
but being in the EL1&0 translation regime.

This is usually expressed as:

	if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu) ... )

which is a mouthful and a bit hard to read, specially when followed
by additional conditions.

Introduce a new helper that encapsulate these two terms, allowing
the above to be written as

	if (is_nested_context(vcpu) ... )

which is both shorter and easier to read, and makes more obvious
the potential for simplification on some code paths.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250708172532.1699409-4-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-07-08 10:40:30 -07:00
Mark Rutland
04c5355b2a KVM: arm64: VHE: Centralize ISBs when returning to host
The VHE hyp code has recently gained a few ISBs. Simplify this to one
unconditional ISB in __kvm_vcpu_run_vhe(), and remove the unnecessary
ISB from the kvm_call_hyp_ret() macro.

While kvm_call_hyp_ret() is also used to invoke
__vgic_v3_get_gic_config(), but no ISB is necessary in that case either.

For the moment, an ISB is left in kvm_call_hyp(), as there are many more
users, and removing the ISB would require a more thorough audit.

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250617133718.4014181-8-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-06-19 13:34:59 +01:00
Mark Rutland
186b58bacd KVM: arm64: Remove ad-hoc CPTR manipulation from kvm_hyp_handle_fpsimd()
The hyp code FPSIMD/SVE/SME trap handling logic has some rather messy
open-coded manipulation of CPTR/CPACR. This is benign for non-nested
guests, but broken for nested guests, as the guest hypervisor's CPTR
configuration is not taken into account.

Consider the case where L0 provides FPSIMD+SVE to an L1 guest
hypervisor, and the L1 guest hypervisor only provides FPSIMD to an L2
guest (with L1 configuring CPTR/CPACR to trap SVE usage from L2). If the
L2 guest triggers an FPSIMD trap to the L0 hypervisor,
kvm_hyp_handle_fpsimd() will see that the vCPU supports FPSIMD+SVE, and
will configure CPTR/CPACR to NOT trap FPSIMD+SVE before returning to the
L2 guest. Consequently the L2 guest would be able to manipulate SVE
state even though the L1 hypervisor had configured CPTR/CPACR to forbid
this.

Clean this up, and fix the nested virt issue by always using
__deactivate_cptr_traps() and __activate_cptr_traps() to manage the CPTR
traps. This removes the need for the ad-hoc fixup in
kvm_hyp_save_fpsimd_host(), and ensures that any guest hypervisor
configuration of CPTR/CPACR is taken into account.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250617133718.4014181-6-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-06-19 13:06:20 +01:00
Mark Rutland
e62dd50784 KVM: arm64: Reorganise CPTR trap manipulation
The NVHE/HVHE and VHE modes have separate implementations of
__activate_cptr_traps() and __deactivate_cptr_traps() in their
respective switch.c files. There's some duplication of logic, and it's
not currently possible to reuse this logic elsewhere.

Move the logic into the common switch.h header so that it can be reused,
and de-duplicate the common logic.

This rework changes the way SVE traps are deactivated in VHE mode,
aligning it with NVHE/HVHE modes:

* Before this patch, VHE's __deactivate_cptr_traps() would
  unconditionally enable SVE for host EL2 (but not EL0), regardless of
  whether the ARM64_SVE cpucap was set.

* After this patch, VHE's __deactivate_cptr_traps() will take the
  ARM64_SVE cpucap into account. When ARM64_SVE is not set, SVE will be
  trapped from EL2 and below.

The old and new behaviour are both benign:

* When ARM64_SVE is not set, the host will not touch SVE state, and will
  not reconfigure SVE traps. Host EL0 access to SVE will be trapped as
  expected.

* When ARM64_SVE is set, the host will configure EL0 SVE traps before
  returning to EL0 as part of reloading the EL0 FPSIMD/SVE/SME state.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250617133718.4014181-4-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-06-19 13:06:19 +01:00
Mark Rutland
cade3d57e4 KVM: arm64: VHE: Synchronize restore of host debug registers
When KVM runs in non-protected VHE mode, there's no context
synchronization event between __debug_switch_to_host() restoring the
host debug registers and __kvm_vcpu_run() unmasking debug exceptions.
Due to this, it's theoretically possible for the host to take an
unexpected debug exception due to the stale guest configuration.

This cannot happen in NVHE/HVHE mode as debug exceptions are masked in
the hyp code, and the exception return to the host will provide the
necessary context synchronization before debug exceptions can be taken.

For now, avoid the problem by adding an ISB after VHE hyp code restores
the host debug registers.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Will Deacon <will@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250617133718.4014181-2-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-06-19 13:06:19 +01:00
Paolo Bonzini
ce360c2bfd KVM/arm64 fixes for 6.16, take #2
- Rework of system register accessors for system registers that are
   directly writen to memory, so that sanitisation of the in-memory
   value happens at the correct time (after the read, or before the
   write). For convenience, RMW-style accessors are also provided.
 
 - Multiple fixes for the so-called "arch-timer-edge-cases' selftest,
   which was always broken.
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Merge tag 'kvmarm-fixes-6.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.16, take #2

- Rework of system register accessors for system registers that are
  directly writen to memory, so that sanitisation of the in-memory
  value happens at the correct time (after the read, or before the
  write). For convenience, RMW-style accessors are also provided.

- Multiple fixes for the so-called "arch-timer-edge-cases' selftest,
  which was always broken.
2025-06-11 14:25:22 -04:00
Marc Zyngier
6678791ee3 KVM: arm64: Add assignment-specific sysreg accessor
Assigning a value to a system register doesn't do what it is
supposed to be doing if that register is one that has RESx bits.

The main problem is that we use __vcpu_sys_reg(), which can be used
both as a lvalue and rvalue. When used as a lvalue, the bit masking
occurs *before* the new value is assigned, meaning that we (1) do
pointless work on the old cvalue, and (2) potentially assign an
invalid value as we fail to apply the masks to it.

Fix this by providing a new __vcpu_assign_sys_reg() that does
what it says on the tin, and sanitises the *new* value instead of
the old one. This comes with a significant amount of churn.

Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250603070824.1192795-2-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-06-05 14:17:32 +01:00
Paolo Bonzini
4d526b02df KVM/arm64 updates for 6.16
* New features:
 
   - Add large stage-2 mapping support for non-protected pKVM guests,
     clawing back some performance.
 
   - Add UBSAN support to the standalone EL2 object used in nVHE/hVHE and
     protected modes.
 
   - Enable nested virtualisation support on systems that support it
     (yes, it has been a long time coming), though it is disabled by
     default.
 
 * Improvements, fixes and cleanups:
 
   - Large rework of the way KVM tracks architecture features and links
     them with the effects of control bits. This ensures correctness of
     emulation (the data is automatically extracted from the published
     JSON files), and helps dealing with the evolution of the
     architecture.
 
   - Significant changes to the way pKVM tracks ownership of pages,
     avoiding page table walks by storing the state in the hypervisor's
     vmemmap. This in turn enables the THP support described above.
 
   - New selftest checking the pKVM ownership transition rules
 
   - Fixes for FEAT_MTE_ASYNC being accidentally advertised to guests
     even if the host didn't have it.
 
   - Fixes for the address translation emulation, which happened to be
     rather buggy in some specific contexts.
 
   - Fixes for the PMU emulation in NV contexts, decoupling PMCR_EL0.N
     from the number of counters exposed to a guest and addressing a
     number of issues in the process.
 
   - Add a new selftest for the SVE host state being corrupted by a
     guest.
 
   - Keep HCR_EL2.xMO set at all times for systems running with the
     kernel at EL2, ensuring that the window for interrupts is slightly
     bigger, and avoiding a pretty bad erratum on the AmpereOne HW.
 
   - Add workaround for AmpereOne's erratum AC04_CPU_23, which suffers
     from a pretty bad case of TLB corruption unless accesses to HCR_EL2
     are heavily synchronised.
 
   - Add a per-VM, per-ITS debugfs entry to dump the state of the ITS
     tables in a human-friendly fashion.
 
   - and the usual random cleanups.
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Merge tag 'kvmarm-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 updates for 6.16

* New features:

  - Add large stage-2 mapping support for non-protected pKVM guests,
    clawing back some performance.

  - Add UBSAN support to the standalone EL2 object used in nVHE/hVHE and
    protected modes.

  - Enable nested virtualisation support on systems that support it
    (yes, it has been a long time coming), though it is disabled by
    default.

* Improvements, fixes and cleanups:

  - Large rework of the way KVM tracks architecture features and links
    them with the effects of control bits. This ensures correctness of
    emulation (the data is automatically extracted from the published
    JSON files), and helps dealing with the evolution of the
    architecture.

  - Significant changes to the way pKVM tracks ownership of pages,
    avoiding page table walks by storing the state in the hypervisor's
    vmemmap. This in turn enables the THP support described above.

  - New selftest checking the pKVM ownership transition rules

  - Fixes for FEAT_MTE_ASYNC being accidentally advertised to guests
    even if the host didn't have it.

  - Fixes for the address translation emulation, which happened to be
    rather buggy in some specific contexts.

  - Fixes for the PMU emulation in NV contexts, decoupling PMCR_EL0.N
    from the number of counters exposed to a guest and addressing a
    number of issues in the process.

  - Add a new selftest for the SVE host state being corrupted by a
    guest.

  - Keep HCR_EL2.xMO set at all times for systems running with the
    kernel at EL2, ensuring that the window for interrupts is slightly
    bigger, and avoiding a pretty bad erratum on the AmpereOne HW.

  - Add workaround for AmpereOne's erratum AC04_CPU_23, which suffers
    from a pretty bad case of TLB corruption unless accesses to HCR_EL2
    are heavily synchronised.

  - Add a per-VM, per-ITS debugfs entry to dump the state of the ITS
    tables in a human-friendly fashion.

  - and the usual random cleanups.
2025-05-26 16:19:46 -04:00
Marc Zyngier
1b85d923ba Merge branch kvm-arm64/misc-6.16 into kvmarm-master/next
* kvm-arm64/misc-6.16:
  : .
  : Misc changes and improvements for 6.16:
  :
  : - Add a new selftest for the SVE host state being corrupted by a guest
  :
  : - Keep HCR_EL2.xMO set at all times for systems running with the kernel at EL2,
  :   ensuring that the window for interrupts is slightly bigger, and avoiding
  :   a pretty bad erratum on the AmpereOne HW
  :
  : - Replace a couple of open-coded on/off strings with str_on_off()
  :
  : - Get rid of the pKVM memblock sorting, which now appears to be superflous
  :
  : - Drop superflous clearing of ICH_LR_EOI in the LR when nesting
  :
  : - Add workaround for AmpereOne's erratum AC04_CPU_23, which suffers from
  :   a pretty bad case of TLB corruption unless accesses to HCR_EL2 are
  :   heavily synchronised
  :
  : - Add a per-VM, per-ITS debugfs entry to dump the state of the ITS tables
  :   in a human-friendly fashion
  : .
  KVM: arm64: Fix documentation for vgic_its_iter_next()
  KVM: arm64: vgic-its: Add debugfs interface to expose ITS tables
  arm64: errata: Work around AmpereOne's erratum AC04_CPU_23
  KVM: arm64: nv: Remove clearing of ICH_LR<n>.EOI if ICH_LR<n>.HW == 1
  KVM: arm64: Drop sort_memblock_regions()
  KVM: arm64: selftests: Add test for SVE host corruption
  KVM: arm64: Force HCR_EL2.xMO to 1 at all times in VHE mode
  KVM: arm64: Replace ternary flags with str_on_off() helper

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-23 10:59:43 +01:00
Marc Zyngier
fef3acf5ae Merge branch kvm-arm64/fgt-masks into kvmarm-master/next
* kvm-arm64/fgt-masks: (43 commits)
  : .
  : Large rework of the way KVM deals with trap bits in conjunction with
  : the CPU feature registers. It now draws a direct link between which
  : the feature set, the system registers that need to UNDEF to match
  : the configuration and bits that need to behave as RES0 or RES1 in
  : the trap registers that are visible to the guest.
  :
  : Best of all, these definitions are mostly automatically generated
  : from the JSON description published by ARM under a permissive
  : license.
  : .
  KVM: arm64: Handle TSB CSYNC traps
  KVM: arm64: Add FGT descriptors for FEAT_FGT2
  KVM: arm64: Allow sysreg ranges for FGT descriptors
  KVM: arm64: Add context-switch for FEAT_FGT2 registers
  KVM: arm64: Add trap routing for FEAT_FGT2 registers
  KVM: arm64: Add sanitisation for FEAT_FGT2 registers
  KVM: arm64: Add FEAT_FGT2 registers to the VNCR page
  KVM: arm64: Use HCR_EL2 feature map to drive fixed-value bits
  KVM: arm64: Use HCRX_EL2 feature map to drive fixed-value bits
  KVM: arm64: Allow kvm_has_feat() to take variable arguments
  KVM: arm64: Use FGT feature maps to drive RES0 bits
  KVM: arm64: Validate FGT register descriptions against RES0 masks
  KVM: arm64: Switch to table-driven FGU configuration
  KVM: arm64: Handle PSB CSYNC traps
  KVM: arm64: Use KVM-specific HCRX_EL2 RES0 mask
  KVM: arm64: Remove hand-crafted masks for FGT registers
  KVM: arm64: Use computed FGT masks to setup FGT registers
  KVM: arm64: Propagate FGT masks to the nVHE hypervisor
  KVM: arm64: Unconditionally configure fine-grain traps
  KVM: arm64: Use computed masks as sanitisers for FGT registers
  ...

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-23 10:58:15 +01:00
Vincent Donnefort
c353fde17d KVM: arm64: np-guest CMOs with PMD_SIZE fixmap
With the introduction of stage-2 huge mappings in the pKVM hypervisor,
guest pages CMO is needed for PMD_SIZE size. Fixmap only supports
PAGE_SIZE and iterating over the huge-page is time consuming (mostly due
to TLBI on hyp_fixmap_unmap) which is a problem for EL2 latency.

Introduce a shared PMD_SIZE fixmap (hyp_fixblock_map/hyp_fixblock_unmap)
to improve guest page CMOs when stage-2 huge mappings are installed.

On a Pixel6, the iterative solution resulted in a latency of ~700us,
while the PMD_SIZE fixmap reduces it to ~100us.

Because of the horrendous private range allocation that would be
necessary, this is disabled for 64KiB pages systems.

Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-11-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21 14:33:51 +01:00
Vincent Donnefort
c4d99a833d KVM: arm64: Add a range to __pkvm_host_test_clear_young_guest()
In preparation for supporting stage-2 huge mappings for np-guest. Add a
nr_pages argument to the __pkvm_host_test_clear_young_guest hypercall.
This range supports only two values: 1 or PMD_SIZE / PAGE_SIZE (that is
512 on a 4K-pages system).

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-7-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21 14:33:51 +01:00
Vincent Donnefort
0eb802b3b4 KVM: arm64: Add a range to __pkvm_host_wrprotect_guest()
In preparation for supporting stage-2 huge mappings for np-guest. Add a
nr_pages argument to the __pkvm_host_wrprotect_guest hypercall. This
range supports only two values: 1 or PMD_SIZE / PAGE_SIZE (that is 512
on a 4K-pages system).

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-6-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21 14:33:51 +01:00
Vincent Donnefort
f28f1d02f4 KVM: arm64: Add a range to __pkvm_host_unshare_guest()
In preparation for supporting stage-2 huge mappings for np-guest. Add a
nr_pages argument to the __pkvm_host_unshare_guest hypercall. This range
supports only two values: 1 or PMD_SIZE / PAGE_SIZE (that is 512 on a
4K-pages system).

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-5-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21 14:33:51 +01:00
Vincent Donnefort
4274385ebf KVM: arm64: Add a range to __pkvm_host_share_guest()
In preparation for supporting stage-2 huge mappings for np-guest. Add a
nr_pages argument to the __pkvm_host_share_guest hypercall. This range
supports only two values: 1 or PMD_SIZE / PAGE_SIZE (that is 512 on a
4K-pages system).

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-4-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21 14:33:51 +01:00
Vincent Donnefort
3db771fa23 KVM: arm64: Introduce for_each_hyp_page
Add a helper to iterate over the hypervisor vmemmap. This will be
particularly handy with the introduction of huge mapping support
for the np-guest stage-2.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Link: https://lore.kernel.org/r/20250521124834.1070650-3-vdonnefort@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21 14:33:51 +01:00
Marc Zyngier
d5702dd224 Merge branch kvm-arm64/pkvm-selftest-6.16 into kvm-arm64/pkvm-np-thp-6.16
* kvm-arm64/pkvm-selftest-6.16:
  : .
  : pKVM selftests covering the memory ownership transitions by
  : Quentin Perret. From the initial cover letter:
  :
  : "We have recently found a bug [1] in the pKVM memory ownership
  : transitions by code inspection, but it could have been caught with a
  : test.
  :
  : Introduce a boot-time selftest exercising all the known pKVM memory
  : transitions and importantly checks the rejection of illegal transitions.
  :
  : The new test is hidden behind a new Kconfig option separate from
  : CONFIG_EL2_NVHE_DEBUG on purpose as that has side effects on the
  : transition checks ([1] doesn't reproduce with EL2 debug enabled).
  :
  : [1] https://lore.kernel.org/kvmarm/20241128154406.602875-1-qperret@google.com/"
  : .
  KVM: arm64: Extend pKVM selftest for np-guests
  KVM: arm64: Selftest for pKVM transitions
  KVM: arm64: Don't WARN from __pkvm_host_share_guest()
  KVM: arm64: Add .hyp.data section

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-21 14:33:43 +01:00
D Scott Phillips
fed55f49fa arm64: errata: Work around AmpereOne's erratum AC04_CPU_23
On AmpereOne AC04, updates to HCR_EL2 can rarely corrupt simultaneous
translations for data addresses initiated by load/store instructions.
Only instruction initiated translations are vulnerable, not translations
from prefetches for example. A DSB before the store to HCR_EL2 is
sufficient to prevent older instructions from hitting the window for
corruption, and an ISB after is sufficient to prevent younger
instructions from hitting the window for corruption.

Signed-off-by: D Scott Phillips <scott@os.amperecomputing.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20250513184514.2678288-1-scott@os.amperecomputing.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-19 12:46:26 +01:00
Marc Zyngier
1ba41c8160 KVM: arm64: Add context-switch for FEAT_FGT2 registers
Just like the rest of the FGT registers, perform a switch of the
FGT2 equivalent. This avoids the host configuration leaking into
the guest...

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-19 11:36:21 +01:00
Marc Zyngier
3ce9bbba93 KVM: arm64: Remove hand-crafted masks for FGT registers
These masks are now useless, and can be removed.

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-10 11:04:35 +01:00
Marc Zyngier
aed34b6d21 KVM: arm64: Use computed FGT masks to setup FGT registers
Flip the hyervisor FGT configuration over to the computed FGT
masks.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-10 11:04:09 +01:00
Marc Zyngier
ffea7c73d1 KVM: arm64: Properly save/restore HCRX_EL2
Rather than restoring HCRX_EL2 to a fixed value on vcpu exit,
perform a full save/restore of the register, ensuring that
we don't lose bits that would have been set at some point in
the host kernel lifetime, such as the GCSEn bit.

Fixes: ff5181d8a2 ("arm64/gcs: Provide basic EL2 setup to allow GCS usage at EL0 and EL1")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250430105916.3815157-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-05-07 00:16:44 -07:00
Mark Rutland
ea266c7249 KVM: arm64: Unconditionally configure fine-grain traps
... otherwise we can inherit the host configuration if this differs from
the KVM configuration.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[maz: simplified a couple of things]
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06 17:35:25 +01:00
Marc Zyngier
09be03c6b5 KVM: arm64: Don't treat HCRX_EL2 as a FGT register
Treating HCRX_EL2 as yet another FGT register seems excessive, and
gets in a way of further improvements. It is actually simpler to
just be explicit about the masking, so just to that.

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06 17:35:19 +01:00
Marc Zyngier
0f013a524b arm64: sysreg: Replace HFGxTR_EL2 with HFG{R,W}TR_EL2
Treating HFGRTR_EL2 and HFGWTR_EL2 identically was a mistake.
It makes things hard to reason about, has the potential to
introduce bugs by giving a meaning to bits that are really reserved,
and is in general a bad description of the architecture.

Given that #defines are cheap, let's describe both registers as
intended by the architecture, and repaint all the existing uses.

Yes, this is painful.

The registers themselves are generated from the JSON file in
an automated way.

Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06 17:35:03 +01:00
Quentin Perret
48d5645072 KVM: arm64: Extend pKVM selftest for np-guests
The pKVM selftest intends to test as many memory 'transitions' as
possible, so extend it to cover sharing pages with non-protected guests,
including in the case of multi-sharing.

Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416160900.3078417-5-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06 09:56:18 +01:00
Quentin Perret
6c2d4c319c KVM: arm64: Selftest for pKVM transitions
We have recently found a bug [1] in the pKVM memory ownership
transitions by code inspection, but it could have been caught with a
test.

Introduce a boot-time selftest exercising all the known pKVM memory
transitions and importantly checks the rejection of illegal transitions.

The new test is hidden behind a new Kconfig option separate from
CONFIG_EL2_NVHE_DEBUG on purpose as that has side effects on the
transition checks ([1] doesn't reproduce with EL2 debug enabled).

[1] https://lore.kernel.org/kvmarm/20241128154406.602875-1-qperret@google.com/

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416160900.3078417-4-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-06 09:56:18 +01:00
Quentin Perret
3390b3cbb6 KVM: arm64: Move hyp state to hyp_vmemmap
Tracking the hypervisor's ownership state into struct hyp_page has
several benefits, including allowing far more efficient lookups (no
page-table walk needed) and de-corelating the state from the presence
of a mapping. This will later allow to map pages into EL2 stage-1 less
proactively which is generally a good thing for security. And in the
future this will help with tracking the state of pages mapped into the
hypervisor's private range without requiring an alias into the 'linear
map' range.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416152648.2982950-6-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-04-28 09:23:46 +01:00
Quentin Perret
ba5b2e5b9d KVM: arm64: Introduce {get,set}_host_state() helpers
Instead of directly accessing the host_state member in struct hyp_page,
introduce static inline accessors to do it. The future hyp_state member
will follow the same pattern as it will need some logic in the accessors.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416152648.2982950-5-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-04-28 09:23:46 +01:00
Quentin Perret
cd4b039165 KVM: arm64: Use 0b11 for encoding PKVM_NOPAGE
The page ownership state encoded as 0b11 is currently considered
reserved for future use, and PKVM_NOPAGE uses bit 2. In order to
simplify the relocation of the hyp ownership state into the
vmemmap in later patches, let's use the 'reserved' encoding for
the PKVM_NOPAGE state. The struct hyp_page layout isn't guaranteed
stable at all, so there is no real reason to have 'reserved' encodings.

No functional changes intended.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416152648.2982950-4-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-04-28 09:23:46 +01:00
Quentin Perret
ba637018ca KVM: arm64: Fix pKVM page-tracking comments
Most of the comments relating to pKVM page-tracking in nvhe/memory.h are
now either slightly outdated or outright wrong. Fix the comments.

Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416152648.2982950-3-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-04-28 09:23:46 +01:00
Oliver Upton
26fbdf3692 KVM: arm64: Don't translate FAR if invalid/unsafe
Don't re-walk the page tables if an SEA occurred during the faulting
page table walk to avoid taking a fatal exception in the hyp.
Additionally, check that FAR_EL2 is valid for SEAs not taken on PTW
as the architecture doesn't guarantee it contains the fault VA.

Finally, fix up the rest of the abort path by checking for SEAs early
and bugging the VM if we get further along with an UNKNOWN fault IPA.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250402201725.2963645-4-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-04-03 00:28:51 -07:00
Oliver Upton
fb8a3eba9c KVM: arm64: Only read HPFAR_EL2 when value is architecturally valid
KVM's logic for deciding when HPFAR_EL2 is UNKNOWN doesn't align with
the architecture. Most notably, KVM assumes HPFAR_EL2 contains the
faulting IPA even in the case of an SEA.

Align the logic with the architecture rather than attempting to
paraphrase it. Additionally, take the opportunity to improve the
language around ARM erratum #834220 such that it actually describes the
bug.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250402201725.2963645-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-04-03 00:28:51 -07:00
Oliver Upton
ca19dd4323 Merge branch 'kvm-arm64/pkvm-6.15' into kvmarm/next
* kvm-arm64/pkvm-6.15:
  : pKVM updates for 6.15
  :
  :  - SecPageTable stats for stage-2 table pages allocated by the protected
  :    hypervisor (Vincent Donnefort)
  :
  :  - HCRX_EL2 trap + vCPU initialization fixes for pKVM (Fuad Tabba)
  KVM: arm64: Create each pKVM hyp vcpu after its corresponding host vcpu
  KVM: arm64: Factor out pKVM hyp vcpu creation to separate function
  KVM: arm64: Initialize HCRX_EL2 traps in pKVM
  KVM: arm64: Factor out setting HCRX_EL2 traps into separate function
  KVM: arm64: Count pKVM stage-2 usage in secondary pagetable stats
  KVM: arm64: Distinct pKVM teardown memcache for stage-2
  KVM: arm64: Add flags to kvm_hyp_memcache

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-19 14:54:40 -07:00
Oliver Upton
4f2774c57a Merge branch 'kvm-arm64/writable-midr' into kvmarm/next
* kvm-arm64/writable-midr:
  : Writable implementation ID registers, courtesy of Sebastian Ott
  :
  : Introduce a new capability that allows userspace to set the
  : ID registers that identify a CPU implementation: MIDR_EL1, REVIDR_EL1,
  : and AIDR_EL1. Also plug a hole in KVM's trap configuration where
  : SMIDR_EL1 was readable at EL1, despite the fact that KVM does not
  : support SME.
  KVM: arm64: Fix documentation for KVM_CAP_ARM_WRITABLE_IMP_ID_REGS
  KVM: arm64: Copy MIDR_EL1 into hyp VM when it is writable
  KVM: arm64: Copy guest CTR_EL0 into hyp VM
  KVM: selftests: arm64: Test writes to MIDR,REVIDR,AIDR
  KVM: arm64: Allow userspace to change the implementation ID registers
  KVM: arm64: Load VPIDR_EL2 with the VM's MIDR_EL1 value
  KVM: arm64: Maintain per-VM copy of implementation ID regs
  KVM: arm64: Set HCR_EL2.TID1 unconditionally

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-19 14:54:32 -07:00
Fuad Tabba
1eab115486 KVM: arm64: Create each pKVM hyp vcpu after its corresponding host vcpu
Instead of creating and initializing _all_ hyp vcpus in pKVM when
the first host vcpu runs for the first time, initialize _each_
hyp vcpu in conjunction with its corresponding host vcpu.

Some of the host vcpu state (e.g., system registers and traps
values) is not initialized until the first time the host vcpu is
run. Therefore, initializing a hyp vcpu before its corresponding
host vcpu has run for the first time might not view the complete
host state of these vcpus.

Additionally, this behavior is inline with non-protected modes.

Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20250314111832.4137161-5-tabba@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-14 16:06:03 -07:00
Vincent Donnefort
8c0d7d14c5 KVM: arm64: Distinct pKVM teardown memcache for stage-2
In order to account for memory dedicated to the stage-2 page-tables, use
a separated memcache when tearing down the VM. Meanwhile rename
reclaim_guest_pages to reflect the fact it only reclaim page-table
pages.

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250313114038.1502357-3-vdonnefort@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-14 00:56:29 -07:00
Oliver Upton
6f34024d18 KVM: arm64: Use a cpucap to determine if system supports FEAT_PMUv3
KVM is about to learn some new tricks to virtualize PMUv3 on IMPDEF
hardware. As part of that, we now need to differentiate host support
from guest support for PMUv3.

Add a cpucap to determine if an architectural PMUv3 is present to guard
host usage of PMUv3 controls.

Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-03-11 12:54:23 -07:00
Sebastian Ott
3adaee7830 KVM: arm64: Allow userspace to change the implementation ID registers
KVM's treatment of the ID registers that describe the implementation
(MIDR, REVIDR, and AIDR) is interesting, to say the least. On the
userspace-facing end of it, KVM presents the values of the boot CPU on
all vCPUs and treats them as invariant. On the guest side of things KVM
presents the hardware values of the local CPU, which can change during
CPU migration in a big-little system.

While one may call this fragile, there is at least some degree of
predictability around it. For example, if a VMM wanted to present
big-little to a guest, it could affine vCPUs accordingly to the correct
clusters.

All of this makes a giant mess out of adding support for making these
implementation ID registers writable. Avoid breaking the rather subtle
ABI around the old way of doing things by requiring opt-in from
userspace to make the registers writable.

When the cap is enabled, allow userspace to set MIDR, REVIDR, and AIDR
to any non-reserved value and present those values consistently across
all vCPUs.

Signed-off-by: Sebastian Ott <sebott@redhat.com>
[oliver: changelog, capability]
Link: https://lore.kernel.org/r/20250225005401.679536-5-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-02-26 01:32:16 -08:00
Oliver Upton
d0d81e03e6 KVM: arm64: Load VPIDR_EL2 with the VM's MIDR_EL1 value
Userspace will soon be able to change the value of MIDR_EL1. Prepare by
loading VPIDR_EL2 with the guest value for non-nested VMs.

Since VPIDR_EL2 is set for any VM, get rid of the NV-specific cleanup of
reloading the hardware value on vcpu_put(). And for nVHE, load the
hardware value before switching to the host.

Link: https://lore.kernel.org/r/20250225005401.679536-4-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2025-02-26 01:32:05 -08:00
Marc Zyngier
65729da9ce KVM: arm64: Convert timer offset VA when accessed in HYP code
Now that EL2 has gained some early timer emulation, it accesses
the offsets pointed to by the timer structure, both of which
live in the KVM structure.

Of course, these are *kernel* pointers, so the dereferencing
of these pointers in non-kernel code must be itself be offset.

Given switch.h its own version of timer_get_offset() and use that
instead.

Fixes: b86fc215dc ("KVM: arm64: Handle counter access early in non-HYP context")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Link: https://lore.kernel.org/r/20250212173454.2864462-1-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-02-13 17:55:13 +00:00
Mark Rutland
59419f1004 KVM: arm64: Eagerly switch ZCR_EL{1,2}
In non-protected KVM modes, while the guest FPSIMD/SVE/SME state is live on the
CPU, the host's active SVE VL may differ from the guest's maximum SVE VL:

* For VHE hosts, when a VM uses NV, ZCR_EL2 contains a value constrained
  by the guest hypervisor, which may be less than or equal to that
  guest's maximum VL.

  Note: in this case the value of ZCR_EL1 is immaterial due to E2H.

* For nVHE/hVHE hosts, ZCR_EL1 contains a value written by the guest,
  which may be less than or greater than the guest's maximum VL.

  Note: in this case hyp code traps host SVE usage and lazily restores
  ZCR_EL2 to the host's maximum VL, which may be greater than the
  guest's maximum VL.

This can be the case between exiting a guest and kvm_arch_vcpu_put_fp().
If a softirq is taken during this period and the softirq handler tries
to use kernel-mode NEON, then the kernel will fail to save the guest's
FPSIMD/SVE state, and will pend a SIGKILL for the current thread.

This happens because kvm_arch_vcpu_ctxsync_fp() binds the guest's live
FPSIMD/SVE state with the guest's maximum SVE VL, and
fpsimd_save_user_state() verifies that the live SVE VL is as expected
before attempting to save the register state:

| if (WARN_ON(sve_get_vl() != vl)) {
|         force_signal_inject(SIGKILL, SI_KERNEL, 0, 0);
|         return;
| }

Fix this and make this a bit easier to reason about by always eagerly
switching ZCR_EL{1,2} at hyp during guest<->host transitions. With this
happening, there's no need to trap host SVE usage, and the nVHE/nVHE
__deactivate_cptr_traps() logic can be simplified to enable host access
to all present FPSIMD/SVE/SME features.

In protected nVHE/hVHE modes, the host's state is always saved/restored
by hyp, and the guest's state is saved prior to exit to the host, so
from the host's PoV the guest never has live FPSIMD/SVE/SME state, and
the host's ZCR_EL1 is never clobbered by hyp.

Fixes: 8c8010d69c ("KVM: arm64: Save/restore SVE state for nVHE")
Fixes: 2e3cf82063 ("KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250210195226.1215254-9-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-02-13 17:55:06 +00:00
Mark Rutland
f9dd00de1e KVM: arm64: Mark some header functions as inline
The shared hyp switch header has a number of static functions which
might not be used by all files that include the header, and when unused
they will provoke compiler warnings, e.g.

| In file included from arch/arm64/kvm/hyp/nvhe/hyp-main.c:8:
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:703:13: warning: 'kvm_hyp_handle_dabt_low' defined but not used [-Wunused-function]
|   703 | static bool kvm_hyp_handle_dabt_low(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:682:13: warning: 'kvm_hyp_handle_cp15_32' defined but not used [-Wunused-function]
|   682 | static bool kvm_hyp_handle_cp15_32(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:662:13: warning: 'kvm_hyp_handle_sysreg' defined but not used [-Wunused-function]
|   662 | static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:458:13: warning: 'kvm_hyp_handle_fpsimd' defined but not used [-Wunused-function]
|   458 | static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:329:13: warning: 'kvm_hyp_handle_mops' defined but not used [-Wunused-function]
|   329 | static bool kvm_hyp_handle_mops(struct kvm_vcpu *vcpu, u64 *exit_code)
|       |             ^~~~~~~~~~~~~~~~~~~

Mark these functions as 'inline' to suppress this warning. This
shouldn't result in any functional change.

At the same time, avoid the use of __alias() in the header and alias
kvm_hyp_handle_iabt_low() and kvm_hyp_handle_watchpt_low() to
kvm_hyp_handle_memory_fault() using CPP, matching the style in the rest
of the kernel. For consistency, kvm_hyp_handle_memory_fault() is also
marked as 'inline'.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250210195226.1215254-8-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-02-13 17:55:03 +00:00
Mark Rutland
9b66195063 KVM: arm64: Refactor exit handlers
The hyp exit handling logic is largely shared between VHE and nVHE/hVHE,
with common logic in arch/arm64/kvm/hyp/include/hyp/switch.h. The code
in the header depends on function definitions provided by
arch/arm64/kvm/hyp/vhe/switch.c and arch/arm64/kvm/hyp/nvhe/switch.c
when they include the header.

This is an unusual header dependency, and prevents the use of
arch/arm64/kvm/hyp/include/hyp/switch.h in other files as this would
result in compiler warnings regarding missing definitions, e.g.

| In file included from arch/arm64/kvm/hyp/nvhe/hyp-main.c:8:
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:733:31: warning: 'kvm_get_exit_handler_array' used but never defined
|   733 | static const exit_handler_fn *kvm_get_exit_handler_array(struct kvm_vcpu *vcpu);
|       |                               ^~~~~~~~~~~~~~~~~~~~~~~~~~
| ./arch/arm64/kvm/hyp/include/hyp/switch.h:735:13: warning: 'early_exit_filter' used but never defined
|   735 | static void early_exit_filter(struct kvm_vcpu *vcpu, u64 *exit_code);
|       |             ^~~~~~~~~~~~~~~~~

Refactor the logic such that the header doesn't depend on anything from
the C files. There should be no functional change as a result of this
patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250210195226.1215254-7-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-02-13 17:55:00 +00:00
Mark Rutland
8eca7f6d51 KVM: arm64: Remove host FPSIMD saving for non-protected KVM
Now that the host eagerly saves its own FPSIMD/SVE/SME state,
non-protected KVM never needs to save the host FPSIMD/SVE/SME state,
and the code to do this is never used. Protected KVM still needs to
save/restore the host FPSIMD/SVE state to avoid leaking guest state to
the host (and to avoid revealing to the host whether the guest used
FPSIMD/SVE/SME), and that code needs to be retained.

Remove the unused code and data structures.

To avoid the need for a stub copy of kvm_hyp_save_fpsimd_host() in the
VHE hyp code, the nVHE/hVHE version is moved into the shared switch
header, where it is only invoked when KVM is in protected mode.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250210195226.1215254-3-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-02-13 17:54:44 +00:00
Marc Zyngier
080612b294 Merge branch kvm-arm64/nv-timers into kvmarm-master/next
* 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>
2025-01-17 11:04:53 +00:00
Marc Zyngier
e880b16efb Merge branch kvm-arm64/pkvm-fixed-features-6.14 into kvmarm-master/next
* 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
2025-01-12 10:40:10 +00:00
Marc Zyngier
d0670128d4 Merge branch kvm-arm64/pkvm-np-guest into kvmarm-master/next
* 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
2025-01-12 10:37:15 +00:00