On Thu, Jun 21, 2018 at 03:57:34PM +0100, Dave Martin wrote:
> Since SVE will be enabled or disabled on a per-vcpu basis, a flag
> is needed in order to track which vcpus have it enabled.
>
> This patch adds a suitable flag and a helper for checking it.
>
> Signed-off-by: Dave Martin <Dave.Martin@xxxxxxx>
> ---
> arch/arm64/include/asm/kvm_host.h | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 9671ddd..609d08b 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -308,6 +308,14 @@ struct kvm_vcpu_arch {
> #define KVM_ARM64_FP_HOST (1 << 2) /* host FP regs loaded */
> #define KVM_ARM64_HOST_SVE_IN_USE (1 << 3) /* backup for host TIF_SVE */
> #define KVM_ARM64_HOST_SVE_ENABLED (1 << 4) /* SVE enabled for EL0 */
> +#define KVM_ARM64_GUEST_HAS_SVE (1 << 5) /* SVE exposed to guest */
> +
> +static inline bool vcpu_has_sve(struct kvm_vcpu_arch const *vcpu_arch)
> +{
> + return system_supports_sve() &&
system_supports_sve() checks cpus_have_const_cap(), not
this_cpu_has_cap(), so, iiuc, the result of this check won't
change, regardless of which cpu it's run on at the time.
> + (vcpu_arch->flags & KVM_ARM64_GUEST_HAS_SVE);
Since this flag can only be set if system_supports_sve() is
true at vcpu init time, then it isn't necessary to always check
system_supports_sve() in this function. Or, should
system_supports_sve() be changed to use this_cpu_has_cap()?
Thanks,
drew
> +
> +}
>
> #define vcpu_gp_regs(v) (&(v)->arch.ctxt.gp_regs)
>
> --
> 2.1.4
>
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