Messages in this thread |  | | Subject | Re: [PATCH v2 5/6] kvm: x86: Emulate MSR IA32_CORE_CAPABILITIES | From | Xiaoyao Li <> | Date | Tue, 4 Feb 2020 17:19:26 +0800 |
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On 2/4/2020 5:43 AM, Sean Christopherson wrote: > On Mon, Feb 03, 2020 at 11:16:07PM +0800, Xiaoyao Li wrote: >> Emulate MSR_IA32_CORE_CAPABILITIES in software and unconditionally >> advertise its support to userspace. Like MSR_IA32_ARCH_CAPABILITIES, it >> is a feature-enumerating MSR and can be fully emulated regardless of >> hardware support. Existence of CORE_CAPABILITIES is enumerated via >> CPUID.(EAX=7H,ECX=0):EDX[30]. >> >> Note, support for individual features enumerated via CORE_CAPABILITIES, >> e.g., split lock detection, will be added in future patches. >> >> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> >> --- >> arch/x86/include/asm/kvm_host.h | 1 + >> arch/x86/kvm/cpuid.c | 5 +++-- >> arch/x86/kvm/x86.c | 22 ++++++++++++++++++++++ >> 3 files changed, 26 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >> index 329d01c689b7..dc231240102f 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -591,6 +591,7 @@ struct kvm_vcpu_arch { >> u64 ia32_xss; >> u64 microcode_version; >> u64 arch_capabilities; >> + u64 core_capabilities; >> >> /* >> * Paging state of the vcpu >> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c >> index b1c469446b07..7282d04f3a6b 100644 >> --- a/arch/x86/kvm/cpuid.c >> +++ b/arch/x86/kvm/cpuid.c >> @@ -409,10 +409,11 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry, int index) >> boot_cpu_has(X86_FEATURE_AMD_SSBD)) >> entry->edx |= F(SPEC_CTRL_SSBD); >> /* >> - * We emulate ARCH_CAPABILITIES in software even >> - * if the host doesn't support it. >> + * ARCH_CAPABILITIES and CORE_CAPABILITIES are emulated in >> + * software regardless of host support. >> */ >> entry->edx |= F(ARCH_CAPABILITIES); >> + entry->edx |= F(CORE_CAPABILITIES); >> break; >> case 1: >> entry->eax &= kvm_cpuid_7_1_eax_x86_features; >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index 821b7404c0fd..a97a8f5dd1df 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -1222,6 +1222,7 @@ static const u32 emulated_msrs_all[] = { >> MSR_IA32_TSC_ADJUST, >> MSR_IA32_TSCDEADLINE, >> MSR_IA32_ARCH_CAPABILITIES, >> + MSR_IA32_CORE_CAPS, >> MSR_IA32_MISC_ENABLE, >> MSR_IA32_MCG_STATUS, >> MSR_IA32_MCG_CTL, >> @@ -1288,6 +1289,7 @@ static const u32 msr_based_features_all[] = { >> MSR_F10H_DECFG, >> MSR_IA32_UCODE_REV, >> MSR_IA32_ARCH_CAPABILITIES, >> + MSR_IA32_CORE_CAPS, >> }; >> >> static u32 msr_based_features[ARRAY_SIZE(msr_based_features_all)]; >> @@ -1341,12 +1343,20 @@ static u64 kvm_get_arch_capabilities(void) >> return data; >> } >> >> +static u64 kvm_get_core_capabilities(void) >> +{ >> + return 0; >> +} >> + >> static int kvm_get_msr_feature(struct kvm_msr_entry *msr) >> { >> switch (msr->index) { >> case MSR_IA32_ARCH_CAPABILITIES: >> msr->data = kvm_get_arch_capabilities(); >> break; >> + case MSR_IA32_CORE_CAPS: >> + msr->data = kvm_get_core_capabilities(); >> + break; >> case MSR_IA32_UCODE_REV: >> rdmsrl_safe(msr->index, &msr->data); >> break; >> @@ -2716,6 +2726,11 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) >> return 1; >> vcpu->arch.arch_capabilities = data; >> break; >> + case MSR_IA32_CORE_CAPS: >> + if (!msr_info->host_initiated) > > Shouldn't @data be checked against kvm_get_core_capabilities()?
Maybe it's for the case that userspace might have the ability to emulate SLD feature? And we usually let userspace set whatever it wants, e.g., ARCH_CAPABILITIES.
Anyway, I have no objection to add this check.
>> + return 1; >> + vcpu->arch.core_capabilities = data; >> + break; >> case MSR_EFER: >> return set_efer(vcpu, msr_info); >> case MSR_K7_HWCR: >> @@ -3044,6 +3059,12 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) >> return 1; >> msr_info->data = vcpu->arch.arch_capabilities; >> break; >> + case MSR_IA32_CORE_CAPS: >> + if (!msr_info->host_initiated && >> + !guest_cpuid_has(vcpu, X86_FEATURE_CORE_CAPABILITIES)) >> + return 1; >> + msr_info->data = vcpu->arch.core_capabilities; >> + break; >> case MSR_IA32_POWER_CTL: >> msr_info->data = vcpu->arch.msr_ia32_power_ctl; >> break; >> @@ -9288,6 +9309,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) >> goto free_guest_fpu; >> >> vcpu->arch.arch_capabilities = kvm_get_arch_capabilities(); >> + vcpu->arch.core_capabilities = kvm_get_core_capabilities(); >> vcpu->arch.msr_platform_info = MSR_PLATFORM_INFO_CPUID_FAULT; >> kvm_vcpu_mtrr_init(vcpu); >> vcpu_load(vcpu); >> -- >> 2.23.0 >>
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