[v1] arm: Implement an emulation of GICv5 interrupt controller

[PATCH 29/65] hw/intc/arm_gicv5: Implement IRS_SYNCR and IRS_SYNC_STATUSR

Posted by Peter Maydell 1 month, 2 weeks ago

The IRS_SYNCR register is used by software to request synchronization
of interrupt events.  This means that in-flight interrupt events are
guaranteed to have been delivered.

Since QEMU's implementation is entirely synchronous, syncs are a
no-op for us.  This means we can ignore writes to IRS_SYNCR and
always report "sync complete" via the IDLE bit in IRS_SYNC_STATUSR.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/intc/arm_gicv5.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/intc/arm_gicv5.c b/hw/intc/arm_gicv5.c
index 5f4c4158c4..d0ba8fe669 100644
--- a/hw/intc/arm_gicv5.c
+++ b/hw/intc/arm_gicv5.c
@@ -1047,6 +1047,10 @@ static bool config_readl(GICv5 *s, GICv5Domain domain, hwaddr offset,
     case A_IRS_CR1:
         *data = cs->irs_cr1[domain];
         return true;
+    case A_IRS_SYNC_STATUSR:
+        /* Sync is a no-op for QEMU: we are always IDLE */
+        *data = R_IRS_SYNC_STATUSR_IDLE_MASK;
+        return true;
     }
 
     return false;
@@ -1132,6 +1136,9 @@ static bool config_writel(GICv5 *s, GICv5Domain domain, hwaddr offset,
     case A_IRS_CR1:
         cs->irs_cr1[domain] = data;
         return true;
+    case A_IRS_SYNCR:
+        /* Sync is a no-op for QEMU: ignore write */
+        return true;
     }
     return false;
 }
-- 
2.43.0

Re: [PATCH 29/65] hw/intc/arm_gicv5: Implement IRS_SYNCR and IRS_SYNC_STATUSR

Posted by Jonathan Cameron via qemu development 1 month ago

On Mon, 23 Feb 2026 17:01:36 +0000
Peter Maydell <peter.maydell@linaro.org> wrote:

> The IRS_SYNCR register is used by software to request synchronization
> of interrupt events.  This means that in-flight interrupt events are
> guaranteed to have been delivered.
> 
> Since QEMU's implementation is entirely synchronous, syncs are a
> no-op for us.  This means we can ignore writes to IRS_SYNCR and
> always report "sync complete" via the IDLE bit in IRS_SYNC_STATUSR.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>