vfio: Pass an error object to vfio_get_group

Pass an error object to prepare for migration to VFIO-PCI realize.

For the time being let's just simply report the error in
vfio platform's vfio_base_device_init(). A subsequent patch will
duly propagate the error up to vfio_platform_realize.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

hw/vfio/common.c

@@ -1123,12 +1123,11 @@ static void vfio_disconnect_container(VFIOGroup *group)
     }
 }
 
-VFIOGroup *vfio_get_group(int groupid, AddressSpace *as)
+VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp)
 {
     VFIOGroup *group;
     char path[32];
     struct vfio_group_status status = { .argsz = sizeof(status) };
-    Error *err = NULL;
 
     QLIST_FOREACH(group, &vfio_group_list, next) {
         if (group->groupid == groupid) {
@@ -1136,7 +1135,7 @@ VFIOGroup *vfio_get_group(int groupid, AddressSpace *as)
             if (group->container->space->as == as) {
                 return group;
             } else {
-                error_report("vfio: group %d used in multiple address spaces",
+                error_setg(errp, "group %d used in multiple address spaces",
                            group->groupid);
                 return NULL;
             }
@@ -1148,27 +1147,28 @@ VFIOGroup *vfio_get_group(int groupid, AddressSpace *as)
     snprintf(path, sizeof(path), "/dev/vfio/%d", groupid);
     group->fd = qemu_open(path, O_RDWR);
     if (group->fd < 0) {
-        error_report("vfio: error opening %s: %m", path);
+        error_setg_errno(errp, errno, "failed to open %s", path);
         goto free_group_exit;
     }
 
     if (ioctl(group->fd, VFIO_GROUP_GET_STATUS, &status)) {
-        error_report("vfio: error getting group status: %m");
+        error_setg_errno(errp, errno, "failed to get group %d status", groupid);
         goto close_fd_exit;
     }
 
     if (!(status.flags & VFIO_GROUP_FLAGS_VIABLE)) {
-        error_report("vfio: error, group %d is not viable, please ensure "
-                     "all devices within the iommu_group are bound to their "
-                     "vfio bus driver.", groupid);
+        error_setg(errp, "group %d is not viable", groupid);
+        error_append_hint(errp,
+                          "Please ensure all devices within the iommu_group "
+                          "are bound to their vfio bus driver.\n");
         goto close_fd_exit;
     }
 
     group->groupid = groupid;
     QLIST_INIT(&group->device_list);
 
-    if (vfio_connect_container(group, as, &err)) {
-        error_reportf_err(err, "vfio: failed to setup container for group %d",
+    if (vfio_connect_container(group, as, errp)) {
+        error_prepend(errp, "failed to setup container for group %d: ",
                       groupid);
         goto close_fd_exit;
     }

hw/vfio/pci.c

@@ -2563,9 +2563,8 @@ static int vfio_initfn(PCIDevice *pdev)
 
     trace_vfio_initfn(vdev->vbasedev.name, groupid);
 
-    group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev));
+    group = vfio_get_group(groupid, pci_device_iommu_address_space(pdev), &err);
     if (!group) {
-        error_setg(&err, "failed to get group %d", groupid);
         ret = -ENOENT;
         goto error;
     }

hw/vfio/platform.c

@@ -552,6 +552,7 @@ static int vfio_base_device_init(VFIODevice *vbasedev)
     ssize_t len;
     struct stat st;
     int groupid;
+    Error *err = NULL;
     int ret;
 
     /* @sysfsdev takes precedence over @host */
@@ -592,10 +593,10 @@ static int vfio_base_device_init(VFIODevice *vbasedev)
 
     trace_vfio_platform_base_device_init(vbasedev->name, groupid);
 
-    group = vfio_get_group(groupid, &address_space_memory);
+    group = vfio_get_group(groupid, &address_space_memory, &err);
     if (!group) {
-        error_report("vfio: failed to get group %d", groupid);
-        return -ENOENT;
+        ret = -ENOENT;
+        goto error;
     }
 
     QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
@@ -619,6 +620,10 @@ static int vfio_base_device_init(VFIODevice *vbasedev)
         vfio_put_group(group);
     }
 
+error:
+    if (err) {
+        error_reportf_err(err, ERR_PREFIX, vbasedev->name);
+    }
     return ret;
 }
 

include/hw/vfio/vfio-common.h

@@ -155,7 +155,7 @@ void vfio_region_mmaps_set_enabled(VFIORegion *region, bool enabled);
 void vfio_region_exit(VFIORegion *region);
 void vfio_region_finalize(VFIORegion *region);
 void vfio_reset_handler(void *opaque);
-VFIOGroup *vfio_get_group(int groupid, AddressSpace *as);
+VFIOGroup *vfio_get_group(int groupid, AddressSpace *as, Error **errp);
 void vfio_put_group(VFIOGroup *group);
 int vfio_get_device(VFIOGroup *group, const char *name,
                     VFIODevice *vbasedev);