On 10/9/24 04:28, Nikunj A Dadhania wrote:
> Add confidential compute platform attribute CC_ATTR_GUEST_SNP_SECURE_TSC
> that can be used by the guest to query whether the Secure TSC feature is
> active.
>
> Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx>
Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
(Although, this can probably be squashed into the next patch where it is
first used)
> ---
> include/linux/cc_platform.h | 8 ++++++++
> arch/x86/coco/core.c | 3 +++
> 2 files changed, 11 insertions(+)
>
> diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h
> index caa4b4430634..cb7103dc124f 100644
> --- a/include/linux/cc_platform.h
> +++ b/include/linux/cc_platform.h
> @@ -88,6 +88,14 @@ enum cc_attr {
> * enabled to run SEV-SNP guests.
> */
> CC_ATTR_HOST_SEV_SNP,
> +
> + /**
> + * @CC_ATTR_GUEST_SNP_SECURE_TSC: SNP Secure TSC is active.
> + *
> + * The platform/OS is running as a guest/virtual machine and actively
> + * using AMD SEV-SNP Secure TSC feature.
> + */
> + CC_ATTR_GUEST_SNP_SECURE_TSC,
> };
>
> #ifdef CONFIG_ARCH_HAS_CC_PLATFORM
> diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
> index 0f81f70aca82..5b9a358a3254 100644
> --- a/arch/x86/coco/core.c
> +++ b/arch/x86/coco/core.c
> @@ -100,6 +100,9 @@ static bool noinstr amd_cc_platform_has(enum cc_attr attr)
> case CC_ATTR_HOST_SEV_SNP:
> return cc_flags.host_sev_snp;
>
> + case CC_ATTR_GUEST_SNP_SECURE_TSC:
> + return sev_status & MSR_AMD64_SNP_SECURE_TSC;
> +
> default:
> return false;
> }
