On Wed, Mar 12, 2025 at 01:24:32PM +0100,
Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> On 10/12/24 09:55, Isaku Yamahata wrote:
> > Add guest_tsc_protected member to struct kvm_arch_vcpu and prohibit
> > changing TSC offset/multiplier when guest_tsc_protected is true.
>
> Thanks Isaku! To match the behavior of the SEV-SNP patches, this is
> also needed, which I have added to kvm-coco-queue:
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index dc2f14a6d8a1..ccde7c2b2248 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3919,7 +3925,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> case MSR_IA32_TSC:
> if (msr_info->host_initiated) {
> kvm_synchronize_tsc(vcpu, &data);
> - } else {
> + } else if (!vcpu->arch.guest_tsc_protected) {
> u64 adj = kvm_compute_l1_tsc_offset(vcpu, data) - vcpu->arch.l1_tsc_offset;
> adjust_tsc_offset_guest(vcpu, adj);
> vcpu->arch.ia32_tsc_adjust_msr += adj;
Thank you for catching this. This looks good.
--
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
