[PATCH v4 7/7] hw/nmi: Raise NMI line only once

["Philippe Mathieu-Daudé" <philmd@oss.qualcomm.com>]

We only expect one device in the system to implement the
TYPE_NMI interface (typically the machine, but in a few cases
for e.g. m68k and ppc this is an interrupt controller or
similar device); so we don't need to keep walking the whole
QOM tree once we've found it. As no machine type creates more
than one object implementing TYPE_NMI, this is not a behaviour
change.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/core/nmi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/core/nmi.c b/hw/core/nmi.c
index c44b0cf892d..84f21665987 100644
--- a/hw/core/nmi.c
+++ b/hw/core/nmi.c
@@ -31,6 +31,11 @@ static int do_nmi(Object *o, void *opaque)
     if (n) {
         *handled = true;
         NMI_GET_CLASS(n)->raise_nmi(n);
+        /*
+         * We expect only one object to implement TYPE_NMI, so once
+         * we've asked it to deliver the NMI we can stop looking.
+         */
+        return 1;
     }
 
     return 0;
-- 
2.53.0