| Message ID | 20221125040604.5051-4-weijiang.yang@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce Architectural LBR for vPMU | expand |
On Thu, Nov 24, 2022, Yang Weijiang wrote: > 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> > --- > 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 6b5912578edd..85e3df6217af 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -272,9 +272,19 @@ 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; ECX and EDX should be left alone, it is userspace's responsibility to provide a sane CPUID model. E.g. KVM doesn't clear EBX or EDX in CPUID.0xD.0x1 when XSAVE is unsupported. > + } > + } > > 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 16726b44061b..888a153e32bc 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -3685,8 +3685,10 @@ 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 >
On 1/27/2023 3:50 AM, Sean Christopherson wrote: > On Thu, Nov 24, 2022, Yang Weijiang wrote: >> 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> >> --- >> 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 6b5912578edd..85e3df6217af 100644 >> --- a/arch/x86/kvm/cpuid.c >> +++ b/arch/x86/kvm/cpuid.c >> @@ -272,9 +272,19 @@ 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; > ECX and EDX should be left alone, it is userspace's responsibility to provide a > sane CPUID model. E.g. KVM doesn't clear EBX or EDX in CPUID.0xD.0x1 when XSAVE > is unsupported. Thanks for review! Sure, I'll remove it. > >> + } >> + } >> >> 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 16726b44061b..888a153e32bc 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -3685,8 +3685,10 @@ 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 >>
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 6b5912578edd..85e3df6217af 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -272,9 +272,19 @@ 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 16726b44061b..888a153e32bc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3685,8 +3685,10 @@ 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)