On Wed, Feb 17, 2021, Maxim Levitsky wrote: > On Wed, 2021-02-17 at 17:06 +0100, Paolo Bonzini wrote: > > On 17/02/21 15:57, Maxim Levitsky wrote: > > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > > > index b3e36dc3f164..e428d69e21c0 100644 > > > --- a/arch/x86/kvm/vmx/vmx.c > > > +++ b/arch/x86/kvm/vmx/vmx.c > > > @@ -6921,13 +6921,15 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu > > > *vcpu) > > > if (unlikely((u16)vmx->exit_reason.basic == > > > EXIT_REASON_MCE_DURING_VMENTRY)) > > > kvm_machine_check(); > > > > > > + if (likely(!vmx->exit_reason.failed_vmentry)) > > > + vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD); > > > + > > > > Any reason for the if? > > Sean Christopherson asked me to do this to avoid updating idt_vectoring_info > on failed > VM entry, to keep things as they were logically before this patch.
Ya, specifically because the field isn't valid if VM-Enter fails. I'm also ok with an unconditional VMREAD if we add a comment stating that it's unnecessary if VM-Enter failed, but faster in the common case.
