Messages in this thread | | | Subject | Re: [PATCH 1/7] KVM: VMX: read idt_vectoring_info a bit earlier | From | Paolo Bonzini <> | Date | Wed, 17 Feb 2021 17:29:26 +0100 |
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On 17/02/21 17:21, Sean Christopherson wrote: > 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.
It's okay, just good to know!
Thanks,
paolo
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