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>
xen-unstable changeset:   23806:4226ea1785b5
xen-unstable date:        Wed Aug 31 15:23:12 2011 +0100

3 files changed, 8 insertions, 6 deletions

diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index de2a56f956..410b9e8cd6 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -1879,7 +1879,7 @@ int hvm_domain_use_pirq(struct domain *d, int pirq)
         return 0;
 
     emuirq = domain_pirq_to_emuirq(d, pirq);
-    if ( emuirq != IRQ_UNBOUND && d->pirq_to_evtchn[pirq] != 0 )
+    if ( emuirq != IRQ_UNBOUND )
         return 1;
     else
         return 0;
diff --git a/xen/arch/x86/physdev.c b/xen/arch/x86/physdev.c
index 2701a7f9e6..fff3544b68 100644
--- a/xen/arch/x86/physdev.c
+++ b/xen/arch/x86/physdev.c
@@ -202,9 +202,6 @@ static int physdev_map_pirq(struct physdev_map_pirq *map)
     if ( ret == 0 )
         map->pirq = pirq;
 
-    if ( !ret && is_hvm_domain(d) )
-        map_domain_emuirq_pirq(d, pirq, IRQ_PT);
-
  done:
     spin_unlock(&d->event_lock);
     spin_unlock(&pcidevs_lock);
@@ -267,7 +264,7 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
         if ( v->domain->arch.pirq_eoi_map )
             evtchn_unmask(v->domain->pirq_to_evtchn[eoi.irq]);
         if ( !is_hvm_domain(v->domain) ||
-             domain_pirq_to_emuirq(v->domain, eoi.irq) == IRQ_PT )
+             domain_pirq_to_irq(v->domain, eoi.irq) > 0 )
             ret = pirq_guest_eoi(v->domain, eoi.irq);
         else
             ret = 0;
@@ -326,7 +323,7 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE(void) arg)
             break;
         irq_status_query.flags = 0;
         if ( is_hvm_domain(v->domain) &&
-             domain_pirq_to_emuirq(v->domain, irq) != IRQ_PT )
+             domain_pirq_to_irq(v->domain, irq) <= 0 )
         {
             ret = copy_to_guest(arg, &irq_status_query, 1) ? -EFAULT : 0;
             break;
diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index c4308ed8f7..fee9a7a484 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -361,6 +361,9 @@ 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);
 
@@ -409,6 +412,8 @@ static long __evtchn_close(struct domain *d1, int port1)
             pirq_guest_unbind(d1, chn1->u.pirq.irq);
         d1->pirq_to_evtchn[chn1->u.pirq.irq] = 0;
         unlink_pirq_port(chn1, d1->vcpu[chn1->notify_vcpu_id]);
+        if ( is_hvm_domain(d1) && domain_pirq_to_irq(d1, chn1->u.pirq.irq) > 0 )
+            unmap_domain_pirq_emuirq(d1, chn1->u.pirq.irq);
         break;
 
     case ECS_VIRQ: