Messages in this thread Patch in this message | | | From | Yang Weijiang <> | Subject | [PATCH 07/19] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS | Date | Thu, 16 Jun 2022 04:46:31 -0400 |
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Updated CPUID.0xD.0x1, which reports the current required storage size of all features enabled via XCR0 | XSS, when the guest's XSS is modified.
Note, KVM does not yet support any XSS based features, i.e. supported_xss is guaranteed to be zero at this time.
Co-developed-by: Zhang Yi Z <yi.z.zhang@linux.intel.com> Signed-off-by: Zhang Yi Z <yi.z.zhang@linux.intel.com> Signed-off-by: Yang Weijiang <weijiang.yang@intel.com> Message-Id: <20220517154100.29983-5-weijiang.yang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- arch/x86/kvm/cpuid.c | 16 +++++++++++++--- arch/x86/kvm/x86.c | 6 ++++-- 2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index d47222ab8e6e..46ca0f1abbcb 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -240,9 +240,19 @@ static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_e best->ebx = xstate_required_size(vcpu->arch.xcr0, false); best = cpuid_entry2_find(entries, nent, 0xD, 1); - if (best && (cpuid_entry_has(best, X86_FEATURE_XSAVES) || - cpuid_entry_has(best, X86_FEATURE_XSAVEC))) - best->ebx = xstate_required_size(vcpu->arch.xcr0, true); + if (best) { + if (cpuid_entry_has(best, X86_FEATURE_XSAVES) || + cpuid_entry_has(best, X86_FEATURE_XSAVEC)) { + u64 xstate = vcpu->arch.xcr0 | vcpu->arch.ia32_xss; + + best->ebx = xstate_required_size(xstate, true); + } + + if (!cpuid_entry_has(best, X86_FEATURE_XSAVES)) { + best->ecx = 0; + best->edx = 0; + } + } best = __kvm_find_kvm_cpuid_features(vcpu, entries, nent); if (kvm_hlt_in_guest(vcpu->kvm) && best && diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f525228168b8..06fbd3daf393 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3605,8 +3605,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) */ if (data & ~kvm_caps.supported_xss) return 1; - vcpu->arch.ia32_xss = data; - kvm_update_cpuid_runtime(vcpu); + if (vcpu->arch.ia32_xss != data) { + vcpu->arch.ia32_xss = data; + kvm_update_cpuid_runtime(vcpu); + } break; case MSR_SMI_COUNT: if (!msr_info->host_initiated) -- 2.27.0
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