On 12/04/2019 04:20, Amit Daniel Kachhap wrote:
> A per vcpu flag is added to check if pointer authentication is
> enabled for the vcpu or not. This flag may be enabled according to
> the necessary user policies and host capabilities.
>
> This patch also adds a helper to check the flag.
>
> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> Cc: Christoffer Dall <christoffer.dall@xxxxxxx>
> Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx
> ---
>
> Changes since v8:
> * Added a new per vcpu flag which will store Pointer Authentication enable
> status instead of checking them again. [Dave Martin]
>
> arch/arm64/include/asm/kvm_host.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 9d57cf8..31dbc7c 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -355,10 +355,14 @@ struct kvm_vcpu_arch {
> #define KVM_ARM64_HOST_SVE_ENABLED (1 << 4) /* SVE enabled for EL0 */
> #define KVM_ARM64_GUEST_HAS_SVE (1 << 5) /* SVE exposed to guest */
> #define KVM_ARM64_VCPU_SVE_FINALIZED (1 << 6) /* SVE config completed */
> +#define KVM_ARM64_GUEST_HAS_PTRAUTH (1 << 7) /* PTRAUTH exposed to guest */
>
> #define vcpu_has_sve(vcpu) (system_supports_sve() && \
> ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))
>
> +#define vcpu_has_ptrauth(vcpu) \
> + ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_PTRAUTH)
> +
Just as for SVE, please first check that the system has PTRAUTH.
Something like:
(cpus_have_const_cap(ARM64_HAS_GENERIC_AUTH_ARCH) && \
((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_PTRAUTH))
This will save an extra load on unsuspecting CPUs thanks to the static
key embedded in the capability structure.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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