[PULL 04/27] hw/vfio/ap: store object indicating AP config changed in a queue

["Cédric Le Goater" <clg@redhat.com>]

From: Rorie Reyes <rreyes@linux.ibm.com>

Creates an object indicating that an AP configuration change event
has been received and stores it in a queue. These objects will later
be used to store event information for an AP configuration change
when the CHSC instruction is intercepted.

Signed-off-by: Rorie Reyes <rreyes@linux.ibm.com>
Reviewed-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20250609164418.17585-3-rreyes@linux.ibm.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 hw/vfio/ap.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index 93c74ebedb937b7058b2c55a8b85559be1d7c9ed..681fd4a4f1cb861cb287fca9ce2134e55ec20323 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -21,6 +21,7 @@
 #include "hw/s390x/css.h"
 #include "qemu/error-report.h"
 #include "qemu/event_notifier.h"
+#include "qemu/lockable.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
@@ -41,6 +42,15 @@ struct VFIOAPDevice {
     EventNotifier cfg_notifier;
 };
 
+typedef struct APConfigChgEvent {
+    QTAILQ_ENTRY(APConfigChgEvent) next;
+} APConfigChgEvent;
+
+static QTAILQ_HEAD(, APConfigChgEvent) cfg_chg_events =
+    QTAILQ_HEAD_INITIALIZER(cfg_chg_events);
+
+static QemuMutex cfg_chg_events_lock;
+
 OBJECT_DECLARE_SIMPLE_TYPE(VFIOAPDevice, VFIO_AP_DEVICE)
 
 static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
@@ -74,12 +84,19 @@ static void vfio_ap_req_notifier_handler(void *opaque)
 
 static void vfio_ap_cfg_chg_notifier_handler(void *opaque)
 {
+    APConfigChgEvent *cfg_chg_event;
     VFIOAPDevice *vapdev = opaque;
 
     if (!event_notifier_test_and_clear(&vapdev->cfg_notifier)) {
         return;
     }
 
+    cfg_chg_event = g_new0(APConfigChgEvent, 1);
+
+    WITH_QEMU_LOCK_GUARD(&cfg_chg_events_lock) {
+        QTAILQ_INSERT_TAIL(&cfg_chg_events, cfg_chg_event, next);
+    }
+
     css_generate_css_crws(0);
 
 }
-- 
2.49.0