On Wed, Aug 10, 2022, Xiaoyao Li wrote: > On 8/6/2022 1:29 AM, Sean Christopherson wrote: > > @@ -2136,6 +2156,23 @@ static int do_get_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data) > > static int do_set_msr(struct kvm_vcpu *vcpu, unsigned index, u64 *data) > > { > > + u64 val; > > + > > + /* > > + * Disallow writes to immutable feature MSRs after KVM_RUN. KVM does > > + * not support modifying the guest vCPU model on the fly, e.g. changing > > + * the nVMX capabilities while L2 is running is nonsensical. Ignore > > + * writes of the same value, e.g. to allow userspace to blindly stuff > > + * all MSRs when emulating RESET. > > + */ > > + if (vcpu->arch.last_vmentry_cpu != -1 && > > can we extract "vcpu->arch.last_vmentry_cpu != -1" into a function like > kvm_vcpu_has_runned() ? Ya, a helper is in order. I'll add a patch in the next version.