On Wed, Dec 05, 2018 at 03:28:58PM -0800, Jim Mattson wrote:
> RDTSCP is supported in legacy mode as well as long mode. The
> IA32_TSC_AUX MSR should be set to the correct guest value before
> entering any guest that supports RDTSCP.
Not that it matters, but even the 64-bit case was wrong since it
was being gated by the (vmx->vcpu.arch.efer & EFER_SCE) check.
Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
>
> Fixes: 4e47c7a6d714 ("KVM: VMX: Add instruction rdtscp support for guest")
> Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
> Reviewed-by: Peter Shier <pshier@xxxxxxxxxx>
> Reviewed-by: Marc Orr <marcorr@xxxxxxxxxx>
> Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx>
> ---
> arch/x86/kvm/vmx.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index c379d0bfdcba9..ad1753e8a85e5 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -3436,9 +3436,6 @@ static void setup_msrs(struct vcpu_vmx *vmx)
> index = __find_msr_index(vmx, MSR_CSTAR);
> if (index >= 0)
> move_msr_up(vmx, index, save_nmsrs++);
> - index = __find_msr_index(vmx, MSR_TSC_AUX);
> - if (index >= 0 && guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP))
> - move_msr_up(vmx, index, save_nmsrs++);
> /*
> * MSR_STAR is only needed on long mode guests, and only
> * if efer.sce is enabled.
> @@ -3451,6 +3448,9 @@ static void setup_msrs(struct vcpu_vmx *vmx)
> index = __find_msr_index(vmx, MSR_EFER);
> if (index >= 0 && update_transition_efer(vmx, index))
> move_msr_up(vmx, index, save_nmsrs++);
> + index = __find_msr_index(vmx, MSR_TSC_AUX);
> + if (index >= 0 && guest_cpuid_has(&vmx->vcpu, X86_FEATURE_RDTSCP))
> + move_msr_up(vmx, index, save_nmsrs++);
>
> vmx->save_nmsrs = save_nmsrs;
> vmx->guest_msrs_dirty = true;
> --
> 2.20.0.rc1.387.gf8505762e3-goog
>
