Re: [PATCH v2 09/11] x86/kvmclock: Use Secure TSC as clock if available

[Tom Lendacky]

On 3/26/23 09:46, Nikunj A Dadhania wrote:
> For AMD SNP guests having Secure TSC enabled, use Secure TSC based
> clocksource instead of kvmclock.

This patch only results in skipping the initialization of KVM clock, it 
doesn't cause Secure TSC to be used as the clocksource.

Thanks,
Tom

> Signed-off-by: Nikunj A Dadhania <nikunj@xxxxxxx>
> ---
>   arch/x86/kernel/kvmclock.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index 0f35d44c56fe..1be342064851 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -288,7 +288,7 @@ void __init kvmclock_init(void)
>   {
>   	u8 flags;
>   
> -	if (!kvm_para_available() || !kvmclock)
> +	if (!kvm_para_available() || !kvmclock || cc_platform_has(CC_ATTR_GUEST_SECURE_TSC))
>   		return;
>   
>   	if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) {