| Message ID | 1514461290.13216247.1479328935760.JavaMail.zimbra@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Nov 16, 2016 at 12:42 PM, Paolo Bonzini <pbonzini@redhat.com> wrote: >> On Fri, Nov 11, 2016 at 12:54 PM, Nadav Amit <nadav.amit@gmail.com> wrote: >> > >> >> On Nov 10, 2016, at 3:40 PM, Kyle Huey <me@kylehuey.com> wrote: >> >> >> >> Hardware support for faulting on the cpuid instruction is not required to >> >> emulate it, because cpuid triggers a VM exit anyways. KVM handles the >> >> relevant >> >> MSRs (MSR_PLATFORM_INFO and MSR_MISC_FEATURES_ENABLE) and upon a >> >> cpuid-induced VM exit checks the cpuid faulting state and the CPL. >> >> kvm_require_cpl is even kind enough to inject the GP fault for us. >> > >> > I think that for consistency you should also revise em_cpuid() of KVM >> > instruction emulator. Otherwise it may be a potential security >> > hazard (as far fetched as it currently seems). >> >> Hmm, ok. Do you know how I can test this code path? > > Try this patch (untested!) Heh, yes, that would do it. Thanks! > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 5382b82462fc..06d940a7c9fa 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -5868,8 +5868,7 @@ static void vmx_set_dr7(struct kvm_vcpu *vcpu, unsigned long val) > > static int handle_cpuid(struct kvm_vcpu *vcpu) > { > - kvm_emulate_cpuid(vcpu); > - return 1; > + return emulate_instruction(vcpu, 0) == EMULATE_DONE; > } > > static int handle_rdmsr(struct kvm_vcpu *vcpu) > > Paolo - Kyle -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 5382b82462fc..06d940a7c9fa 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5868,8 +5868,7 @@ static void vmx_set_dr7(struct kvm_vcpu *vcpu, unsigned long val) static int handle_cpuid(struct kvm_vcpu *vcpu) { - kvm_emulate_cpuid(vcpu); - return 1; + return emulate_instruction(vcpu, 0) == EMULATE_DONE; } static int handle_rdmsr(struct kvm_vcpu *vcpu)