On 28/01/2015 17:02, Wincy Van wrote:
> +static int vmx_deliver_nested_posted_interrupt(struct kvm_vcpu *vcpu,
> + int vector)
> +{
> + if (is_guest_mode(vcpu) &&
> + vector == to_vmx(vcpu)->nested.posted_intr_nv &&
> + vcpu->mode == IN_GUEST_MODE) {
> + /* the PIR and ON have been set by L1. */
What happens if there is a L2->L0->L2 exit on the target VCPU, and the
guest exits before apic->send_IPI_mask sends the IPI?
The L1 hypervisor might "know" somehow that there cannot be a concurrent
L2->L1->L2 exit, and not do the equivalent of KVM's
kvm_make_request(KVM_REQ_EVENT, vcpu);
after it sets ON.
So I think you have to do something like
static bool vmx_is_nested_posted_interrupt(struct kvm_vcpu *vcpu,
int vector)
{
return (is_guest_mode(vcpu) &&
vector == to_vmx(vcpu)->nested.posted_intr_nv);
}
and in vmx_deliver_posted_interrupt:
r = 0;
if (!vmx_is_nested_posted_interrupt(vcpu, vector)) {
if (pi_test_and_set_pir(vector, &vmx->pi_desc))
return;
r = pi_test_and_set_on(&vmx->pi_desc);
}
kvm_make_request(KVM_REQ_EVENT, vcpu);
#ifdef CONFIG_SMP
if (!r && (vcpu->mode == IN_GUEST_MODE))
apic->send_IPI_mask(get_cpu_mask(vcpu->cpu),
POSTED_INTR_VECTOR);
else
#endif
kvm_vcpu_kick(vcpu);
What do you think?
Paolo
> + apic->send_IPI_mask(get_cpu_mask(vcpu->cpu),
> + POSTED_INTR_VECTOR);
> + return 0;
> + }
> + return -1;
> +}
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