----- chao.gao@xxxxxxxxx wrote: > Although L2 is in halt state, it will be in the active state after > VM entry if the VM entry is vectoring according to SDM 26.6.2 > Activity > State. Halting the vcpu here means the event won't be injected to L2 > and this decision isn't reported to L1. Thus L0 drops an event that > should be injected to L2. > > Cc: Liran Alon <liran.alon@xxxxxxxxxx> > Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx> > --- > Changes in v2: > - Remove VID stuff. Only handle event injection in this patch. > --- > arch/x86/kvm/vmx.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index bb5b488..42f39d9 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -10985,7 +10985,12 @@ static int nested_vmx_run(struct kvm_vcpu > *vcpu, bool launch) > if (ret) > return ret; > > - if (vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) > + /* > + * If we're entering a halted L2 vcpu and the L2 vcpu won't be > woken > + * by event injection, halt vcpu for optimization. I would remove the "for optimization." from the comment. > + */ > + if ((vmcs12->guest_activity_state == GUEST_ACTIVITY_HLT) && > + !(vmcs12->vm_entry_intr_info_field & > VECTORING_INFO_VALID_MASK)) VECTORING_INFO_VALID_MASK is used in KVM code against vmcs12->idt_vectoring_info_field. I think you should use INTR_INFO_VALID_MASK to be consistent with rest of code. > return kvm_vcpu_halt(vcpu); > > vmx->nested.nested_run_pending = 1; > -- > 1.9.1 In addition, commit title should be written in format of: "KVM: VMX: Don't halt vcpu when L1 is injecting events to L2" (Makes it easier to grep in git log). Other than that, seems good to me. :) Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx> Thanks, -Liran
