[Qemu-devel] [PATCH 12/15] hw/intc/arm_gic: Change behavior of IAR writes

[Fabian Aggeler <aggelerf@ethz.ch>]

Grouping (GICv2) and Security Extensions change the behavior of IAR
reads. Acknowledging Group0 interrupts is only allowed from Secure
state and acknowledging Group1 interrupts from Secure state is only
allowed if AckCtl bit is set.

Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch>
---
 hw/intc/arm_gic.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index a96f4a2..cddad45 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -189,11 +189,35 @@ uint32_t gic_acknowledge_irq(GICState *s, int cpu)
     int ret, irq, src;
     int cm = 1 << cpu;
     irq = s->current_pending[cpu];
+    bool isGrp0;
     if (irq == 1023
             || GIC_GET_PRIORITY(irq, cpu) >= s->running_priority[cpu]) {
         DPRINTF("ACK no pending IRQ\n");
         return 1023;
     }
+
+    if (s->revision >= 2 || s->security_extn) {
+        isGrp0 = GIC_TEST_GROUP0(irq, (1 << cpu));
+        if ((isGrp0 && (!s->enabled_grp[0]
+                    || !(s->cpu_control[cpu][0] & GICC_CTLR_S_EN_GRP0)))
+           || (!isGrp0 && (!s->enabled_grp[1]
+                    || !(s->cpu_control[cpu][1] & GICC_CTLR_NS_EN_GRP1)))) {
+            return 1023;
+        }
+
+        if ((s->revision >= 2 && !s->security_extn)
+                || (s->security_extn && !ns_access())) {
+            if (!isGrp0 && !(s->cpu_control[cpu][0] & GICC_CTLR_S_ACK_CTL)) {
+                DPRINTF("Read of IAR ignored for Group1 interrupt %d "
+                        "(AckCtl disabled)\n", irq);
+                return 1022;
+            }
+        } else if (s->security_extn && ns_access() && isGrp0) {
+            DPRINTF("Non-secure read of IAR ignored for Group0 interrupt %d\n",
+                    irq);
+            return 1023;
+        }
+    }
     s->last_active[irq][cpu] = s->running_irq[cpu];
 
     if (s->revision == REV_11MPCORE || s->revision == REV_NVIC) {
-- 
1.8.3.2