xen: fix hvm_domain_use_pirq's behavior

hvm_domain_use_pirq should return true when the guest is using a
certain pirq, no matter if the corresponding event channel is
currently enabled or disabled.  As an additional complication, qemu is
going to request pirqs for passthrough devices even for Xen unaware
HVM guests, so we need to wait for an event channel to be connected
before considering the pirq of a passthrough device as "in use".

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index 631bbede22..0628120c24 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -366,6 +366,9 @@ static long evtchn_bind_pirq(evtchn_bind_pirq_t *bind)
 
     bind->port = port;
 
+    if ( is_hvm_domain(d) && domain_pirq_to_irq(d, pirq) > 0 )
+        map_domain_emuirq_pirq(d, pirq, IRQ_PT);
+
  out:
     spin_unlock(&d->event_lock);
 
@@ -419,6 +422,8 @@ static long __evtchn_close(struct domain *d1, int port1)
         pirq->evtchn = 0;
         pirq_cleanup_check(pirq, d1);
         unlink_pirq_port(chn1, d1->vcpu[chn1->notify_vcpu_id]);
+        if ( is_hvm_domain(d1) && domain_pirq_to_irq(d1, pirq->pirq) > 0 )
+            unmap_domain_pirq_emuirq(d1, pirq->pirq);
         break;
     }