[PATCH 2/3] KVM: x86: Update vCPU's runtime CPUID on write to MSR_IA32_XSS

[Sean Christopherson]

From: Like Xu <likexu@xxxxxxxxxxx>

Do a runtime CPUID update for a vCPU if MSR_IA32_XSS is written, as the
size in bytes of the XSAVE area is affected by the states enabled in XSS.

Fixes: 203000993de5 ("kvm: vmx: add MSR logic for XSAVES")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
[sean: split out as a separate patch, adjust Fixes tag]
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 arch/x86/kvm/x86.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c0727939684e..13793582f26d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3535,6 +3535,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (data & ~supported_xss)
 			return 1;
 		vcpu->arch.ia32_xss = data;
+		kvm_update_cpuid_runtime(vcpu);
 		break;
 	case MSR_SMI_COUNT:
 		if (!msr_info->host_initiated)
-- 
2.35.0.rc0.227.g00780c9af4-goog