[Qemu-devel] [PULL 23/47] vfio: listener unregister before unset container

[Paolo Bonzini]

From: Peter Xu <address@hidden>

After next patch, listener unregister will need the container to be
alive.  Let's move this unregister phase to be before unset container,
since that operation will free the backend container in kernel,
otherwise we'll get these after next patch:

qemu-system-x86_64: VFIO_UNMAP_DMA: -22
qemu-system-x86_64: vfio_dma_unmap(0x559bf53a4590, 0x0, 0xa0000) = -22 (Invalid 
argument)

Signed-off-by: Peter Xu <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Paolo Bonzini <address@hidden>
Acked-by: Alex Williamson <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
 hw/vfio/common.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index b77be3a..76cf28d 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -1161,19 +1161,27 @@ static void vfio_disconnect_container(VFIOGroup *group)
 {
     VFIOContainer *container = group->container;
 
+    QLIST_REMOVE(group, container_next);
+    group->container = NULL;
+
+    /*
+     * Explicitly release the listener first before unset container,
+     * since unset may destroy the backend container if it's the last
+     * group.
+     */
+    if (QLIST_EMPTY(&container->group_list)) {
+        vfio_listener_release(container);
+    }
+
     if (ioctl(group->fd, VFIO_GROUP_UNSET_CONTAINER, &container->fd)) {
         error_report("vfio: error disconnecting group %d from container",
                      group->groupid);
     }
 
-    QLIST_REMOVE(group, container_next);
-    group->container = NULL;
-
     if (QLIST_EMPTY(&container->group_list)) {
         VFIOAddressSpace *space = container->space;
         VFIOGuestIOMMU *giommu, *tmp;
 
-        vfio_listener_release(container);
         QLIST_REMOVE(container, next);
 
         QLIST_FOREACH_SAFE(giommu, &container->giommu_list, giommu_next, tmp) {
-- 
1.8.3.1