Re: [PATCH v3 04/36] KVM: arm64: Don't advertise unsupported features for protected guests

Fuad Tabba
2026-03-11T10:16:37Z

On Thu, 5 Mar 2026 at 14:44, Will Deacon <will@kernel.org> wrote:
>
> Both SVE and PMUv3 are treated as "restricted" features for protected
> guests and attempts to access their corresponding architectural state
> from a protected guest result in an undefined exception being injected
> by the hypervisor.
>
> Since these exceptions are unexpected and typically fatal for the guest,
> don't advertise these features for protected guests.
>
> Signed-off-by: Will Deacon <will@kernel.org>

Reviewed-by: Fuad Tabba <tabba@google.com>

Cheers,
/fuad

> ---
> arch/arm64/include/asm/kvm_pkvm.h | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h
> index 757076ad4ec9..7041e398fb4c 100644
> --- a/arch/arm64/include/asm/kvm_pkvm.h
> +++ b/arch/arm64/include/asm/kvm_pkvm.h
> @@ -40,8 +40,6 @@ static inline bool kvm_pkvm_ext_allowed(struct kvm *kvm, long ext)
> case KVM_CAP_MAX_VCPU_ID:
> case KVM_CAP_MSI_DEVID:
> case KVM_CAP_ARM_VM_IPA_SIZE:
> - case KVM_CAP_ARM_PMU_V3:
> - case KVM_CAP_ARM_SVE:
> case KVM_CAP_ARM_PTRAUTH_ADDRESS:
> case KVM_CAP_ARM_PTRAUTH_GENERIC:
> return true;
> --
> 2.53.0.473.g4a7958ca14-goog
>