Re: [PATCH 2/6] kvm: nVMX: move nested events check to kvm_vcpu_running

Radim Krčmář
2017-02-07T18:16:04Z

2016-12-19 17:17+0100, Paolo Bonzini:
> vcpu_run calls kvm_vcpu_running, not kvm_arch_vcpu_runnable,
> and the former does not call check_nested_events.
>
> Once KVM_REQ_EVENT is removed from the APICv interrupt injection
> path, however, this would leave no place to trigger a vmexit
> from L2 to L1, causing a missed interrupt delivery while in guest
> mode. This is caught by the "ack interrupt on exit" test in
> vmx.flat.
>
> [This does not change the calls to check_nested_events in
> inject_pending_event. That is material for a separate cleanup.]
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---

I think we should now remove the call to check_nested_events() from
inject_pending_event() and we could also call it in vcpu_enter_guest()
directly.

Still,

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com

> arch/x86/kvm/x86.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d5a5fc2f8758..32e5f54a8eba 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6920,6 +6920,9 @@ static inline int vcpu_block(struct kvm *kvm, struct kvm_vcpu *vcpu)
>
> static inline bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
> {
> + if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events)
> + kvm_x86_ops->check_nested_events(vcpu, false);
> +
> return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
> !vcpu->arch.apf.halted);
> }
> @@ -8286,9 +8289,6 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
>
> int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
> {
> - if (is_guest_mode(vcpu) && kvm_x86_ops->check_nested_events)
> - kvm_x86_ops->check_nested_events(vcpu, false);
> -
> return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu);
> }
>
> --
> 1.8.3.1
>
>
> --
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