Re: [PATCH v2] KVM: x86: Update Xen TSC leaves during CPUID emulation

[Durrant, Paul]

On 24/01/2025 15:05, Fred Griffoul wrote:
> The Xen emulation in KVM modifies certain CPUID leaves to expose
> TSC information to the guest.
>
> Previously, these CPUID leaves were updated whenever guest time changed,
> but this conflicts with KVM_SET_CPUID/KVM_SET_CPUID2 ioctls which reject
> changes to CPUID entries on running vCPUs.
>
> Fix this by updating the TSC information directly in the CPUID emulation
> handler instead of modifying the vCPU's CPUID entries.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Signed-off-by: Fred Griffoul <fgriffo@xxxxxxxxxxxx>
> ---
>   arch/x86/kvm/cpuid.c | 16 ++++++++++++++++
>   arch/x86/kvm/x86.c   |  3 +--
>   arch/x86/kvm/x86.h   |  1 +
>   arch/x86/kvm/xen.c   | 23 -----------------------
>   arch/x86/kvm/xen.h   | 13 +++++++++++--
>   5 files changed, 29 insertions(+), 27 deletions(-)

Reviewed-by: Paul Durrant <paul@xxxxxxx>