kvm: vmx: Set IA32_TSC_AUX for legacy mode guests
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Message ID 20181109173421.177250-1-jmattson@google.com
State New
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Series
  • kvm: vmx: Set IA32_TSC_AUX for legacy mode guests
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Commit Message

Jim Mattson Nov. 9, 2018, 5:34 p.m. UTC
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.

Fixes: 4e47c7a6d714 ("KVM: VMX: Add instruction rdtscp support for guest")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
---
 arch/x86/kvm/vmx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Liran Alon Nov. 9, 2018, 7:15 p.m. UTC | #1
> On 9 Nov 2018, at 19:34, Jim Mattson <jmattson@google.com> 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.
> 
> Fixes: 4e47c7a6d714 ("KVM: VMX: Add instruction rdtscp support for guest")
> Signed-off-by: Jim Mattson <jmattson@google.com>
> Reviewed-by: Peter Shier <pshier@google.com>
> Reviewed-by: Marc Orr <marcorr@google.com>
> ---
> 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 ccc6a01eb4f4..120fc97a63fc 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -3415,9 +3415,6 @@ 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.
> @@ -3430,6 +3427,9 @@ 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;
> 
> -- 
> 2.19.1.930.g4563a0d9d0-goog
> 

Reviewed-by: Liran Alon <liran.alon@oracle.com>

Patch
diff mbox series

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ccc6a01eb4f4..120fc97a63fc 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3415,9 +3415,6 @@  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.
@@ -3430,6 +3427,9 @@  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;