Re: [PATCH] KVM: x86: Pending interrupt may be delivered after INIT

Gleb Natapov
2014-06-30T08:47:14Z

On Mon, Jun 30, 2014 at 11:35:27AM +0300, Nadav Amit wrote:
> We encountered a scenario in which after an INIT is delivered, a pending
> interrupt is delivered, although it was sent before the INIT. As the SDM
> states in section 10.4.7.1, the ISR and the IRR should be cleared after INIT as
> KVM does. This also means that pending interrupts should be cleared. This
> patch clears upon reset (and INIT) the pending interrupts; and at the same
> occassion clears the pending exceptions, since they may cause a similar issue.
>
> Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
> ---
> arch/x86/kvm/x86.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index f32a025..863ac07 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6835,6 +6835,8 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu)
> atomic_set(&vcpu->arch.nmi_queued, 0);
> vcpu->arch.nmi_pending = 0;
> vcpu->arch.nmi_injected = false;
> + vcpu->arch.interrupt.pending = false;
> + vcpu->arch.exception.pending = false;
kvm_clear_interrupt_queue(vcpu);
kvm_clear_exception_queue(vcpu);

>
> memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
> vcpu->arch.dr6 = DR6_FIXED_1;
> --
> 1.9.1
>

--
Gleb.