[PATCH-4.5 v2 04/10] xen/arm: set GICH_HCR_UIE if all the LRs are in use

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

On return to guest, if there are no free LRs and we still have more
interrupt to inject, set GICH_HCR_UIE so that we are going to receive a
maintenance interrupt when no pending interrupts are present in the LR
registers.
The maintenance interrupt handler won't do anything anymore, but
receiving the interrupt is going to cause gic_inject to be called on
return to guest that is going to clear the old LRs and inject new
interrupts.

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

---

Changes in v2:
- disable/enable the GICH_HCR_UIE bit in GICH_HCR;
- only enable GICH_HCR_UIE if this_cpu(lr_mask) == ((1 << nr_lrs) - 1).

---
 xen/arch/arm/gic.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
index ee383bc..0928aca 100644
--- a/xen/arch/arm/gic.c
+++ b/xen/arch/arm/gic.c
@@ -805,8 +805,15 @@ void gic_inject(void)
     gic_restore_pending_irqs(current);
     if (!gic_events_need_delivery())
         gic_inject_irq_stop();
-    else
+    else {
         gic_inject_irq_start();
+    }
+
+    if ( !list_empty(&current->arch.vgic.lr_pending) &&
+         this_cpu(lr_mask) == ((1 << nr_lrs) - 1) )
+        GICH[GICH_HCR] |= GICH_HCR_UIE;
+    else
+        GICH[GICH_HCR] &= ~GICH_HCR_UIE;
 }
 
 int gic_route_irq_to_guest(struct domain *d, const struct dt_irq *irq,
-- 
1.7.10.4