pci: add VMSTATE_MSIX

Using a trick cut+pasted from vmstate_scsi_device
to wind up msix_save and msix_load.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

hw/pci/msix.c

@@ -569,3 +569,36 @@ void msix_unset_vector_notifiers(PCIDevice *dev)
     dev->msix_vector_release_notifier = NULL;
     dev->msix_vector_poll_notifier = NULL;
 }
+
+static void put_msix_state(QEMUFile *f, void *pv, size_t size)
+{
+    msix_save(pv, f);
+}
+
+static int get_msix_state(QEMUFile *f, void *pv, size_t size)
+{
+    msix_load(pv, f);
+    return 0;
+}
+
+static VMStateInfo vmstate_info_msix = {
+    .name = "msix state",
+    .get  = get_msix_state,
+    .put  = put_msix_state,
+};
+
+const VMStateDescription vmstate_msix = {
+    .name = "msix",
+    .fields = (VMStateField[]) {
+        {
+            .name         = "msix",
+            .version_id   = 0,
+            .field_exists = NULL,
+            .size         = 0,   /* ouch */
+            .info         = &vmstate_info_msix,
+            .flags        = VMS_SINGLE,
+            .offset       = 0,
+        },
+        VMSTATE_END_OF_LIST()
+    }
+};

include/hw/pci/msix.h

@@ -43,4 +43,15 @@ int msix_set_vector_notifiers(PCIDevice *dev,
                               MSIVectorReleaseNotifier release_notifier,
                               MSIVectorPollNotifier poll_notifier);
 void msix_unset_vector_notifiers(PCIDevice *dev);
+
+extern const VMStateDescription vmstate_msix;
+
+#define VMSTATE_MSIX(_field, _state) {                               \
+    .name       = (stringify(_field)),                               \
+    .size       = sizeof(PCIDevice),                                 \
+    .vmsd       = &vmstate_msix,                                     \
+    .flags      = VMS_STRUCT,                                        \
+    .offset     = vmstate_offset_value(_state, _field, PCIDevice),   \
+}
+
 #endif