hw/intc/arm_gic: Fix writes to GICD_ITARGETSRn

According to the GICv2 specification section 4.3.12, "Interrupt Processor
Targets Registers, GICD_ITARGETSRn":

"Any change to a CPU targets field value:
[...]
* Has an effect on any pending interrupts. This means:
  - adding a CPU interface to the target list of a pending interrupt makes that
    interrupt pending on that CPU interface
  - removing a CPU interface from the target list of a pending interrupt
    removes the pending state of that interrupt on that CPU interface."

Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
Message-id: 20240524113256.8102-3-sebastian.huber@embedded-brains.de
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
index 04e5a11..8068324 100644
--- a/hw/intc/arm_gic.c
+++ b/hw/intc/arm_gic.c
@@ -1410,6 +1410,13 @@ static void gic_dist_writeb(void *opaque, hwaddr offset,
                 value = ALL_CPU_MASK;
             }
             s->irq_target[irq] = value & ALL_CPU_MASK;
+            if (irq >= GIC_INTERNAL && s->irq_state[irq].pending) {
+                /*
+                 * Changing the target of an interrupt that is currently
+                 * pending updates the set of CPUs it is pending on.
+                 */
+                s->irq_state[irq].pending = value & ALL_CPU_MASK;
+            }
         }
     } else if (offset < 0xf00) {
         /* Interrupt Configuration.  */