xen/arm: disable a physical IRQ when the guest disables the corresponding IRQ

In vgic_disable_irqs remove irqs from the lr_pending queue so that they
won't get automatically injected in the guest on maintenance interrupts.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Julien Grall <julien.grall@linaro.org>

xen/arch/arm/gic.c

@@ -649,6 +649,16 @@ static inline void gic_add_to_lr_pending(struct vcpu *v, unsigned int irq,
     list_add_tail(&n->lr_queue, &v->arch.vgic.lr_pending);
 }
 
+void gic_remove_from_queues(struct vcpu *v, unsigned int virtual_irq)
+{
+    struct pending_irq *p = irq_to_pending(v, virtual_irq);
+
+    spin_lock(&gic.lock);
+    if ( !list_empty(&p->lr_queue) )
+        list_del_init(&p->lr_queue);
+    spin_unlock(&gic.lock);
+}
+
 void gic_set_guest_irq(struct vcpu *v, unsigned int virtual_irq,
         unsigned int state, unsigned int priority)
 {

xen/arch/arm/vgic.c

@@ -360,6 +360,23 @@ read_as_zero:
     return 1;
 }
 
+static void vgic_disable_irqs(struct vcpu *v, uint32_t r, int n)
+{
+    struct pending_irq *p;
+    unsigned int irq;
+    int i = 0;
+
+    while ( (i = find_next_bit((const long unsigned int *) &r, 32, i)) < 32 ) {
+        irq = i + (32 * n);
+        p = irq_to_pending(v, irq);
+        clear_bit(GIC_IRQ_GUEST_ENABLED, &p->status);
+        gic_remove_from_queues(v, irq);
+        if ( p->desc != NULL )
+            p->desc->handler->disable(p->desc);
+        i++;
+    }
+}
+
 static void vgic_enable_irqs(struct vcpu *v, uint32_t r, int n)
 {
     struct pending_irq *p;
@@ -490,8 +507,10 @@ static int vgic_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         rank = vgic_irq_rank(v, 1, gicd_reg - GICD_ICENABLER);
         if ( rank == NULL) goto write_ignore;
         vgic_lock_rank(v, rank);
+        tr = rank->ienable;
         rank->ienable &= ~*r;
         vgic_unlock_rank(v, rank);
+        vgic_disable_irqs(v, (*r) & tr, gicd_reg - GICD_ICENABLER);
         return 1;
 
     case GICD_ISPENDR ... GICD_ISPENDRN:

xen/include/asm-arm/gic.h

@@ -158,6 +158,7 @@ extern int gic_events_need_delivery(void);
 extern void __cpuinit init_maintenance_interrupt(void);
 extern void gic_set_guest_irq(struct vcpu *v, unsigned int irq,
         unsigned int state, unsigned int priority);
+extern void gic_remove_from_queues(struct vcpu *v, unsigned int virtual_irq);
 extern int gic_route_irq_to_guest(struct domain *d,
                                   const struct dt_irq *irq,
                                   const char * devname);