----- pbonzini@xxxxxxxxxx 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. > > 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 Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx> The only thing I a bit dislike is that currently these MSRs are always pass-through to guest and therefore there is no case vmx_set_msr() is called with !msr_info->host_initiated. Don't you think we should BUG_ON(!msr_info->host_initiated)? -Liran
