[PATCH v3] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save

[PATCH v3] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save

[Mingwei Zhang]

Add MSR_IA32_TSX_CTRL into msrs_to_save[] to explicitly tell userspace to
save/restore the register value during migration. Missing this may cause
userspace that relies on KVM ioctl(KVM_GET_MSR_INDEX_LIST) fail to port the
value to the target VM.

In addition, there is no need to add MSR_IA32_TSX_CTRL when
ARCH_CAP_TSX_CTRL_MSR is not supported in kvm_get_arch_capabilities(). So
add the checking in kvm_probe_msr_to_save().

Fixes: c11f83e0626b ("KVM: vmx: implement MSR_IA32_TSX_CTRL disable RTM functionality")
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
 arch/x86/kvm/x86.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 237c483b1230..c8accbd6c861 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1431,7 +1431,7 @@ static const u32 msrs_to_save_base[] = {
 #endif
 	MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
 	MSR_IA32_FEAT_CTL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
-	MSR_IA32_SPEC_CTRL,
+	MSR_IA32_SPEC_CTRL, MSR_IA32_TSX_CTRL,
 	MSR_IA32_RTIT_CTL, MSR_IA32_RTIT_STATUS, MSR_IA32_RTIT_CR3_MATCH,
 	MSR_IA32_RTIT_OUTPUT_BASE, MSR_IA32_RTIT_OUTPUT_MASK,
 	MSR_IA32_RTIT_ADDR0_A, MSR_IA32_RTIT_ADDR0_B,
@@ -7077,6 +7077,10 @@ static void kvm_probe_msr_to_save(u32 msr_index)
 		if (!kvm_cpu_cap_has(X86_FEATURE_XFD))
 			return;
 		break;
+	case MSR_IA32_TSX_CTRL:
+		if (!(kvm_get_arch_capabilities() & ARCH_CAP_TSX_CTRL_MSR))
+			return;
+		break;
 	default:
 		break;
 	}
-- 
2.40.1.521.gf1e218fcd8-goog

Re: [PATCH v3] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save

[Mingwei Zhang]

On Mon, May 8, 2023 at 8:23 PM Mingwei Zhang <mizhang@google.com> wrote:
>
> Add MSR_IA32_TSX_CTRL into msrs_to_save[] to explicitly tell userspace to
> save/restore the register value during migration. Missing this may cause
> userspace that relies on KVM ioctl(KVM_GET_MSR_INDEX_LIST) fail to port the
> value to the target VM.
>
> In addition, there is no need to add MSR_IA32_TSX_CTRL when
> ARCH_CAP_TSX_CTRL_MSR is not supported in kvm_get_arch_capabilities(). So
> add the checking in kvm_probe_msr_to_save().
>
> Fixes: c11f83e0626b ("KVM: vmx: implement MSR_IA32_TSX_CTRL disable RTM functionality")
> Reported-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Mingwei Zhang <mizhang@google.com>
> ---

Sign... missed the following two Reviewed-by...

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Jim Mattson <jmattson@google.com>

Since this is probably the final version, I hope Sean or Paolo would
help add them up before merging it. Appreciate your help. Thanks.

-Mingwei

Re: [PATCH v3] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save

[Paolo Bonzini]

On 5/9/23 05:23, Mingwei Zhang wrote:
> Add MSR_IA32_TSX_CTRL into msrs_to_save[] to explicitly tell userspace to
> save/restore the register value during migration. Missing this may cause
> userspace that relies on KVM ioctl(KVM_GET_MSR_INDEX_LIST) fail to port the
> value to the target VM.
> 
> In addition, there is no need to add MSR_IA32_TSX_CTRL when
> ARCH_CAP_TSX_CTRL_MSR is not supported in kvm_get_arch_capabilities(). So
> add the checking in kvm_probe_msr_to_save().
> 
> Fixes: c11f83e0626b ("KVM: vmx: implement MSR_IA32_TSX_CTRL disable RTM functionality")
> Reported-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Mingwei Zhang <mizhang@google.com>
> ---
>   arch/x86/kvm/x86.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 237c483b1230..c8accbd6c861 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1431,7 +1431,7 @@ static const u32 msrs_to_save_base[] = {
>   #endif
>   	MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
>   	MSR_IA32_FEAT_CTL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
> -	MSR_IA32_SPEC_CTRL,
> +	MSR_IA32_SPEC_CTRL, MSR_IA32_TSX_CTRL,
>   	MSR_IA32_RTIT_CTL, MSR_IA32_RTIT_STATUS, MSR_IA32_RTIT_CR3_MATCH,
>   	MSR_IA32_RTIT_OUTPUT_BASE, MSR_IA32_RTIT_OUTPUT_MASK,
>   	MSR_IA32_RTIT_ADDR0_A, MSR_IA32_RTIT_ADDR0_B,
> @@ -7077,6 +7077,10 @@ static void kvm_probe_msr_to_save(u32 msr_index)
>   		if (!kvm_cpu_cap_has(X86_FEATURE_XFD))
>   			return;
>   		break;
> +	case MSR_IA32_TSX_CTRL:
> +		if (!(kvm_get_arch_capabilities() & ARCH_CAP_TSX_CTRL_MSR))
> +			return;
> +		break;
>   	default:
>   		break;
>   	}

Queued, thanks.

Paolo