[PATCH v3 1/3] vfio/pci: Fix resource leak in vfio_realize

[Zhenzhong Duan <zhenzhong.duan@intel.com>]

When adding migration blocker failed in vfio_migration_realize(),
hotplug will fail and we see below:

(qemu) device_add vfio-pci,host=81:11.1,id=vfio1,bus=root1,x-enable-migration=true
0000:81:11.1: VFIO migration is not supported in kernel
Error: disallowing migration blocker (--only-migratable) for: VFIO device doesn't support migration

If we hotplug again we should see same log as above, but we see:
(qemu) device_add vfio-pci,host=81:11.0,id=vfio0,bus=root0,x-enable-migration=true
Error: vfio 0000:81:11.0: device is already attached

That's because some references to VFIO device isn't released,
we should check return value of vfio_migration_realize() and
release the references, then VFIO device will be truely
released when hotplug failed.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
---
 hw/vfio/pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 73874a94de12..c71b0955d81c 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -3210,6 +3210,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
         ret = vfio_migration_realize(vbasedev, errp);
         if (ret) {
             error_report("%s: Migration disabled", vbasedev->name);
+            goto out_deregister;
         }
     }
 
-- 
2.34.1