On 16/01/2018 01:55, Eric Wheeler wrote: > On Tue, 9 Jan 2018, Paolo Bonzini wrote: >> MSR_IA32_SPEC_CTRL is not available unless CPU[7,0].EDX[26] is 1. >> Check that against host CPUID or guest CPUID, respectively for >> host-initiated and guest-initiated accesses. > > Hi Radim, Paolo: > > In porting this patch series to v4.14 Just don't apply this patch. Paolo > In file included from arch/x86/kvm/vmx.c:21:0: > In function 'x86_feature_cpuid', > inlined from 'guest_cpuid_get_register' at arch/x86/kvm/cpuid.h:72:25, > inlined from 'vmx_get_msr' at arch/x86/kvm/cpuid.h:101:6: > arch/x86/kvm/cpuid.h:64:232: error: call to '__compiletime_assert_64' > declared with attribute error: BUILD_BUG_ON failed: > reverse_cpuid[x86_leaf].function == 0 > BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0); > > ^ > In function 'x86_feature_cpuid', > inlined from 'guest_cpuid_get_register' at arch/x86/kvm/cpuid.h:72:25, > inlined from 'vmx_set_msr' at arch/x86/kvm/cpuid.h:101:6: > arch/x86/kvm/cpuid.h:64:232: error: call to '__compiletime_assert_64' > declared with attribute error: BUILD_BUG_ON failed: > reverse_cpuid[x86_leaf].function == 0 > BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0); > > > I think this is caused by the following call stack for > X86_FEATURE_SPEC_CTRL, but if not please correct me here: > > arch/x86/kvm/vmx.c: > vmx_get_msr/vmx_set_msr() > guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL) > guest_cpuid_get_register(vcpu, x86_feature); > x86_feature_cpuid(x86_feature); > x86_feature_cpuid(unsigned x86_feature) > BUILD_BUG_ON(reverse_cpuid[x86_leaf].function == 0); > > > It looks like I need to add something to reverse_cpuid[] but I'm not sure > what. > > Do you know what needs to be added here? > > -Eric > > -- > Eric Wheeler > > > >> >> Suggested-by: Jim Mattson <jmattson@xxxxxxxxxx> >> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> >> --- >> This is for after X86_FEATURE_SPEC_CTRL is added to Linux, but >> I still wanted to ack Jim's improvement. >> >> arch/x86/kvm/svm.c | 8 ++++++++ >> arch/x86/kvm/vmx.c | 8 ++++++++ >> 2 files changed, 16 insertions(+) >> >> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c >> index 97126c2bd663..3a646580d7c5 100644 >> --- a/arch/x86/kvm/svm.c >> +++ b/arch/x86/kvm/svm.c >> @@ -3648,6 +3648,10 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) >> msr_info->data = svm->nested.vm_cr_msr; >> break; >> case MSR_IA32_SPEC_CTRL: >> + if (!static_cpu_has(X86_FEATURE_SPEC_CTRL) || >> + (!msr_info->host_initiated && >> + !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))) >> + return 1; >> msr_info->data = svm->spec_ctrl; >> break; >> case MSR_IA32_UCODE_REV: >> @@ -3806,6 +3810,10 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) >> vcpu_unimpl(vcpu, "unimplemented wrmsr: 0x%x data 0x%llx\n", ecx, data); >> break; >> case MSR_IA32_SPEC_CTRL: >> + if (!static_cpu_has(X86_FEATURE_SPEC_CTRL) || >> + (!msr_info->host_initiated && >> + !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))) >> + return 1; >> svm->spec_ctrl = data; >> break; >> case MSR_IA32_APICBASE: >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index 49b4a2d61603..42bc7ee293e4 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -3368,6 +3368,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) >> msr_info->data = guest_read_tsc(vcpu); >> break; >> case MSR_IA32_SPEC_CTRL: >> + if (!static_cpu_has(X86_FEATURE_SPEC_CTRL) || >> + (!msr_info->host_initiated && >> + !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))) >> + return 1; >> msr_info->data = to_vmx(vcpu)->spec_ctrl; >> break; >> case MSR_IA32_SYSENTER_CS: >> @@ -3510,6 +3514,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) >> kvm_write_tsc(vcpu, msr_info); >> break; >> case MSR_IA32_SPEC_CTRL: >> + if (!static_cpu_has(X86_FEATURE_SPEC_CTRL) || >> + (!msr_info->host_initiated && >> + !guest_cpuid_has(vcpu, X86_FEATURE_SPEC_CTRL))) >> + return 1; >> to_vmx(vcpu)->spec_ctrl = data; >> break; >> case MSR_IA32_CR_PAT: >> -- >> 1.8.3.1 >> >>
