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* [PATCH v2] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save
@ 2023-05-04 18:18 Mingwei Zhang
  2023-05-04 18:26 ` Jim Mattson
  2023-05-08  1:54 ` Xiaoyao Li
  0 siblings, 2 replies; 5+ messages in thread
From: Mingwei Zhang @ 2023-05-04 18:18 UTC (permalink / raw)
  To: Sean Christopherson, Paolo Bonzini
  Cc: H. Peter Anvin, kvm, linux-kernel, Jim Mattson, 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 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(-)

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


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2023-05-09  3:16 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-05-04 18:18 [PATCH v2] KVM: VMX: add MSR_IA32_TSX_CTRL into msrs_to_save Mingwei Zhang
2023-05-04 18:26 ` Jim Mattson
2023-05-08  1:54 ` Xiaoyao Li
2023-05-08 17:28   ` Jim Mattson
2023-05-09  3:15     ` Mingwei Zhang

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