On Mon, Jun 01, 2020 at 03:24:15PM -0700, Jim Mattson wrote:
> As we already do in svm, record the last logical processor on which a
> vCPU has run, so that it can be communicated to userspace for
> potential hardware errors.
>
> Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
> Reviewed-by: Oliver Upton <oupton@xxxxxxxxxx>
> Reviewed-by: Peter Shier <pshier@xxxxxxxxxx>
> ---
> arch/x86/kvm/vmx/vmx.c | 1 +
> arch/x86/kvm/vmx/vmx.h | 3 +++
> 2 files changed, 4 insertions(+)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 170cc76a581f..42856970d3b8 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6730,6 +6730,7 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
> if (vcpu->arch.cr2 != read_cr2())
> write_cr2(vcpu->arch.cr2);
>
> + vmx->last_cpu = vcpu->cpu;
This is redundant in the EXIT_FASTPATH_REENTER_GUEST case. Setting it
before reenter_guest is technically wrong if emulation_required is true, but
that doesn't seem like it'd be an issue in practice.
> vmx->fail = __vmx_vcpu_run(vmx, (unsigned long *)&vcpu->arch.regs,
> vmx->loaded_vmcs->launched);
>
> diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
> index 672c28f17e49..8a1e833cf4fb 100644
> --- a/arch/x86/kvm/vmx/vmx.h
> +++ b/arch/x86/kvm/vmx/vmx.h
> @@ -302,6 +302,9 @@ struct vcpu_vmx {
> u64 ept_pointer;
>
> struct pt_desc pt_desc;
> +
> + /* which host CPU was used for running this vcpu */
> + unsigned int last_cpu;
Why not put this in struct kvm_vcpu_arch? I'd also vote to name it
last_run_cpu, as last_cpu is super misleading.
And if it's in arch, what about setting it vcpu_enter_guest?
> };
>
> enum ept_pointers_status {
> --
> 2.27.0.rc2.251.g90737beb825-goog
>
