KVM: PPC: Tell guest about pending interrupts

When the guest turns on interrupts again, it needs to know if we have an
interrupt pending for it. Because if so, it should rather get out of guest
context and get the interrupt.

So we introduce a new field in the shared page that we use to tell the guest
that there's a pending interrupt lying around.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 104d0ee8c8aa..c604277011a6 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -224,6 +224,7 @@ static int kvmppc_booke_irqprio_deliver(struct kvm_vcpu *vcpu,
 void kvmppc_core_deliver_interrupts(struct kvm_vcpu *vcpu)
 {
         unsigned long *pending = &vcpu->arch.pending_exceptions;
+        unsigned long old_pending = vcpu->arch.pending_exceptions;
         unsigned int priority;
 
         priority = __ffs(*pending);
@@ -235,6 +236,12 @@ void kvmppc_core_deliver_interrupts(struct kvm_vcpu *vcpu)
                                          BITS_PER_BYTE * sizeof(*pending),
                                          priority + 1);
         }
+
+        /* Tell the guest about our interrupt status */
+        if (*pending)
+                vcpu->arch.shared->int_pending = 1;
+        else if (old_pending)
+                vcpu->arch.shared->int_pending = 0;
 }
 
 /**