diff mbox series

[v2] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save

Message ID 20230504181827.130532-1-mizhang@google.com
State New
Headers
Series [v2] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save |

Commit Message

Mingwei Zhang May 4, 2023, 6:18 p.m. UTC 
  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 guest. So add the checking in
kvm_probe_msr_to_save().

Fixes: b07a5c53d42a ("KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it")
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(-)

Comments

Jim Mattson May 4, 2023, 6:26 p.m. UTC | #1 
On Thu, May 4, 2023 at 11:18 AM 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 guest. So add the checking in
> kvm_probe_msr_to_save().
>
> Fixes: b07a5c53d42a ("KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it")
> Reported-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Mingwei Zhang <mizhang@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Xiaoyao Li May 8, 2023, 1:54 a.m. UTC | #2 
On 5/5/2023 2:18 AM, 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 guest. So add the checking in
> kvm_probe_msr_to_save().
> 
> Fixes: b07a5c53d42a ("KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it")

I wonder it's the fix for this commit.

Apart from this,

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>

> 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;
>   	}
Jim Mattson May 8, 2023, 5:28 p.m. UTC | #3 
On Sun, May 7, 2023 at 6:54 PM Xiaoyao Li <xiaoyao.li@intel.com> wrote:
>
> On 5/5/2023 2:18 AM, 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 guest. So add the checking in
> > kvm_probe_msr_to_save().
> >
> > Fixes: b07a5c53d42a ("KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it")
>
> I wonder it's the fix for this commit.
>
> Apart from this,
>
> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>

I concur.

How about:

Fixes: ea732b38b341 ("KVM: vmx: implement MSR_IA32_TSX_CTRL disable
RTM functionality")

Reviewed-by: Jim Mattson <jmattson@google.com>
Mingwei Zhang May 9, 2023, 3:15 a.m. UTC | #4 
On Mon, May 8, 2023 at 10:28 AM Jim Mattson <jmattson@google.com> wrote:
>
> On Sun, May 7, 2023 at 6:54 PM Xiaoyao Li <xiaoyao.li@intel.com> wrote:
> >
> > On 5/5/2023 2:18 AM, 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 guest. So add the checking in
> > > kvm_probe_msr_to_save().
> > >
> > > Fixes: b07a5c53d42a ("KVM: vmx: use MSR_IA32_TSX_CTRL to hard-disable TSX on guest that lack it")
> >
> > I wonder it's the fix for this commit.
> >
> > Apart from this,
> >
> > Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
>
> I concur.
>
> How about:
>
> Fixes: ea732b38b341 ("KVM: vmx: implement MSR_IA32_TSX_CTRL disable
> RTM functionality")
>
> Reviewed-by: Jim Mattson <jmattson@google.com>

Will send a v3 with the update of the "Fixes"
diff mbox series

Patch

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;
 	}