This allows to update the Error argument of the VFIO log_global_start()
handler. Errors for container based logging will also be propagated to
qemu_savevm_state_setup() when the ram save_setup() handler is executed.
Also, errors from vfio_container_set_dirty_page_tracking() are now
collected and reported.

The vfio_set_migration_error() call becomes redundant in
vfio_listener_log_global_start(). Remove it.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---

 Changes in v7:

 - Commit log improvements (Eric)
 
 hw/vfio/common.c | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 485e53916491f1164d29e739fb7106c0c77df737..b5102f54a6474a50c6366e8fbce23812d55e384e 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1027,7 +1027,8 @@ static void vfio_device_feature_dma_logging_start_destroy(
     g_free(feature);
 }
 
-static int vfio_devices_dma_logging_start(VFIOContainerBase *bcontainer)
+static int vfio_devices_dma_logging_start(VFIOContainerBase *bcontainer,
+                                          Error **errp)
 {
     struct vfio_device_feature *feature;
     VFIODirtyRanges ranges;
@@ -1038,6 +1039,7 @@ static int vfio_devices_dma_logging_start(VFIOContainerBase *bcontainer)
     feature = vfio_device_feature_dma_logging_start_create(bcontainer,
                                                            &ranges);
     if (!feature) {
+        error_setg_errno(errp, errno, "Failed to prepare DMA logging");
         return -errno;
     }
 
@@ -1049,8 +1051,8 @@ static int vfio_devices_dma_logging_start(VFIOContainerBase *bcontainer)
         ret = ioctl(vbasedev->fd, VFIO_DEVICE_FEATURE, feature);
         if (ret) {
             ret = -errno;
-            error_report("%s: Failed to start DMA logging, err %d (%s)",
-                         vbasedev->name, ret, strerror(errno));
+            error_setg_errno(errp, errno, "%s: Failed to start DMA logging",
+                             vbasedev->name);
             goto out;
         }
         vbasedev->dirty_tracking = true;
@@ -1069,20 +1071,19 @@ out:
 static bool vfio_listener_log_global_start(MemoryListener *listener,
                                            Error **errp)
 {
+    ERRP_GUARD();
     VFIOContainerBase *bcontainer = container_of(listener, VFIOContainerBase,
                                                  listener);
     int ret;
 
     if (vfio_devices_all_device_dirty_tracking(bcontainer)) {
-        ret = vfio_devices_dma_logging_start(bcontainer);
+        ret = vfio_devices_dma_logging_start(bcontainer, errp);
     } else {
-        ret = vfio_container_set_dirty_page_tracking(bcontainer, true, NULL);
+        ret = vfio_container_set_dirty_page_tracking(bcontainer, true, errp);
     }
 
     if (ret) {
-        error_report("vfio: Could not start dirty page tracking, err: %d (%s)",
-                     ret, strerror(-ret));
-        vfio_set_migration_error(ret);
+        error_prepend(errp, "vfio: Could not start dirty page tracking - ");
     }
     return !ret;
 }
@@ -1091,17 +1092,20 @@ static void vfio_listener_log_global_stop(MemoryListener *listener)
 {
     VFIOContainerBase *bcontainer = container_of(listener, VFIOContainerBase,
                                                  listener);
+    Error *local_err = NULL;
     int ret = 0;
 
     if (vfio_devices_all_device_dirty_tracking(bcontainer)) {
         vfio_devices_dma_logging_stop(bcontainer);
     } else {
-        ret = vfio_container_set_dirty_page_tracking(bcontainer, false, NULL);
+        ret = vfio_container_set_dirty_page_tracking(bcontainer, false,
+                                                     &local_err);
     }
 
     if (ret) {
-        error_report("vfio: Could not stop dirty page tracking, err: %d (%s)",
-                     ret, strerror(-ret));
+        error_prepend(&local_err,
+                      "vfio: Could not stop dirty page tracking - ");
+        error_report_err(local_err);
         vfio_set_migration_error(ret);
     }
 }
-- 
2.45.0