----- pbonzini@xxxxxxxxxx wrote:
> On 08/02/2018 13:09, Liran Alon wrote:
> > ----- pbonzini@xxxxxxxxxx wrote:
> >> On 08/02/2018 06:13, Chao Gao wrote:
> >
> > A possible patch to fix this is to change vmx_hwapic_irr_update()
> such that
> > if is_guest_mode(vcpu)==true, we should return max(max_irr, rvi) and
> return
> > that value into apic_has_interrupt_for_ppr().
> > Need to verify that it doesn't break other flows but I think it
> makes sense.
> > What do you think?
>
> Yeah, I think it makes sense though I'd need to look a lot more at
> arch/x86/kvm/lapic.c and arch/x86/kvm/vmx.c to turn that into a
> patch!
>
> Paolo
After thinking about this a bit more, I don't like my previous suggestion.
As we don't semantically want to change the value returned from kvm_apic_has_interrupt().
Instead, it makes more sense to change kvm_cpu_has_interrupt() to check for RVI>PPR
in case is_guest_mode(vcpu)==true.
Something like (partial theoretical patch):
@@ -97,6 +97,14 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
if (kvm_cpu_has_extint(v))
return 1;
+ /*
+ * When running L2, L1 controls vmcs02 RVI via vmcs12.
+ * Therefore, it is possible RVI indicates pending interrupt
+ * for vCPU while LAPIC IRR is empty.
+ */
+ if (is_guest_mode(v) &&
+ (kvm_x86_ops->hwapic_has_interrupt(v) != -1))
+ return 1;
+
return kvm_apic_has_interrupt(v) != -1; /* LAPIC */
}
Where:
+static int vmx_get_rvi(void)
+{
+ return ((u8)vmcs_read16(GUEST_INTR_STATUS) & 0xff);
+}
+static int vmx_hwapic_has_interrupt(struct kvm_vcpu *vcpu)
+{
+ int vector = vmx_get_rvi(vcpu);
+ return kvm_apic_has_interrupt_for_vector(vector);
+}
+int kvm_apic_has_interrupt_for_vector(struct kvm_vcpu *vcpu, int vector)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+ u32 ppr;
+
+ if (!apic_enabled(apic))
+ return -1;
+
+ __apic_update_ppr(apic, &ppr);
+ return (((vector & 0xF0) > ppr) ? (vector) : (-1));
+}
+EXPORT_SYMBOL_GPL(kvm_apic_has_interrupt_for_vector);
Regards,
-Liran
