[PATCH v2 2/2] xen/arm: observe itarget setting in vgic_enable_irqs and vgic_disable_irqs

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

vgic_enable_irqs should enable irq delivery to the vcpu specified by
GICD_ITARGETSR, rather than the vcpu that wrote to GICD_ISENABLER.
Similarly vgic_disable_irqs should use the target vcpu specified by
itarget to disable irqs.

Correctly initialize itargets for SPIs.

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

---

Changes in v2:
- refactor the common code in get_target_vcpu;
- unify PPI and SPI paths;
- correctly initialize itargets for SPI;
- use byte_read.
---
 xen/arch/arm/vgic.c |   43 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 35 insertions(+), 8 deletions(-)

diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 1304b5e..55ed27d 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -106,7 +106,15 @@ int domain_vgic_init(struct domain *d)
         INIT_LIST_HEAD(&d->arch.vgic.pending_irqs[i].lr_queue);
     }
     for (i=0; i<DOMAIN_NR_RANKS(d); i++)
+    {
+        int j;
+
         spin_lock_init(&d->arch.vgic.shared_irqs[i].lock);
+        /* Only delivery to CPU0 */
+        for ( j = 0 ; j < 8 ; j++ )
+            d->arch.vgic.shared_irqs[i].itargets[j] =
+                (1<<0) | (1<<8) | (1<<16) | (1<<24);
+    }
     return 0;
 }
 
@@ -369,6 +377,21 @@ read_as_zero:
     return 1;
 }
 
+static struct vcpu *get_target_vcpu(struct vcpu *v, unsigned int irq)
+{
+    int target;
+    struct vgic_irq_rank *rank;
+    struct vcpu *v_target;
+
+    rank = vgic_irq_rank(v, 1, irq/32);
+    vgic_lock_rank(v, rank);
+    target = byte_read(rank->itargets[(irq%32)/4], 0, irq % 4);
+    target = find_next_bit((const unsigned long *) &target, 8, 0);
+    v_target = v->domain->vcpu[target];
+    vgic_unlock_rank(v, rank);
+    return v_target;
+}
+
 static void vgic_disable_irqs(struct vcpu *v, uint32_t r, int n)
 {
     const unsigned long mask = r;
@@ -376,12 +399,14 @@ static void vgic_disable_irqs(struct vcpu *v, uint32_t r, int n)
     unsigned int irq;
     unsigned long flags;
     int i = 0;
+    struct vcpu *v_target;
 
     while ( (i = find_next_bit(&mask, 32, i)) < 32 ) {
         irq = i + (32 * n);
-        p = irq_to_pending(v, irq);
+        v_target = get_target_vcpu(v, irq);
+        p = irq_to_pending(v_target, irq);
         clear_bit(GIC_IRQ_GUEST_ENABLED, &p->status);
-        gic_remove_from_queues(v, irq);
+        gic_remove_from_queues(v_target, irq);
         if ( p->desc != NULL )
         {
             spin_lock_irqsave(&p->desc->lock, flags);
@@ -399,24 +424,26 @@ static void vgic_enable_irqs(struct vcpu *v, uint32_t r, int n)
     unsigned int irq;
     unsigned long flags;
     int i = 0;
+    struct vcpu *v_target;
 
     while ( (i = find_next_bit(&mask, 32, i)) < 32 ) {
         irq = i + (32 * n);
-        p = irq_to_pending(v, irq);
+        v_target = get_target_vcpu(v, irq);
+        p = irq_to_pending(v_target, irq);
         set_bit(GIC_IRQ_GUEST_ENABLED, &p->status);
         /* We need to force the first injection of evtchn_irq because
          * evtchn_upcall_pending is already set by common code on vcpu
          * creation. */
-        if ( irq == v->domain->arch.evtchn_irq &&
+        if ( irq == v_target->domain->arch.evtchn_irq &&
              vcpu_info(current, evtchn_upcall_pending) &&
              list_empty(&p->inflight) )
-            vgic_vcpu_inject_irq(v, irq);
+            vgic_vcpu_inject_irq(v_target, irq);
         else {
             unsigned long flags;
-            spin_lock_irqsave(&v->arch.vgic.lock, flags);
+            spin_lock_irqsave(&v_target->arch.vgic.lock, flags);
             if ( !list_empty(&p->inflight) && !test_bit(GIC_IRQ_GUEST_VISIBLE, &p->status) )
-                gic_raise_guest_irq(v, irq, p->priority);
-            spin_unlock_irqrestore(&v->arch.vgic.lock, flags);
+                gic_raise_guest_irq(v_target, irq, p->priority);
+            spin_unlock_irqrestore(&v_target->arch.vgic.lock, flags);
         }
         if ( p->desc != NULL )
         {
-- 
1.7.10.4