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vfio/migration: Free resources when vfio_migration_realize fails 

When vfio_realize() succeeds, hot unplug will call vfio_exitfn()
to free resources allocated in vfio_realize(); when vfio_realize()
fails, vfio_exitfn() is never called and we need to free resources
in vfio_realize().

In the case that vfio_migration_realize() fails,
e.g: with -only-migratable & enable-migration=off, we see below:

(qemu) device_add vfio-pci,host=81:11.1,id=vfio1,bus=root1,enable-migration=off
0000:81:11.1: Migration disabled
Error: disallowing migration blocker (--only-migratable) for: 0000:81:11.1: Migration is disabled for VFIO device

If we hotplug again we should see same log as above, but we see:
(qemu) device_add vfio-pci,host=81:11.1,id=vfio1,bus=root1,enable-migration=off
Error: vfio 0000:81:11.1: device is already attached

That's because some references to VFIO device isn't released.
For resources allocated in vfio_migration_realize(), free them by
jumping to out_deinit path with calling a new function
vfio_migration_deinit(). For resources allocated in vfio_realize(),
free them by jumping to de-register path in vfio_realize().

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Fixes: a22651053b ("vfio: Make vfio-pci device migration capable")
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
Zhenzhong Duan 2023-07-03 15:15:08 +08:00 committed by Cédric Le Goater
parent 3c26c80a0a
commit 2b43b2995b
2 changed files with 24 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
hw/vfio/migration.c
View File

@ -802,6 +802,17 @@ static int vfio_migration_init(VFIODevice *vbasedev)
return 0;
}
static void vfio_migration_deinit(VFIODevice *vbasedev)
{
VFIOMigration *migration = vbasedev->migration;
remove_migration_state_change_notifier(&migration->migration_state);
qemu_del_vm_change_state_handler(migration->vm_state);
unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
vfio_migration_free(vbasedev);
vfio_unblock_multiple_devices_migration();
}
static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp)
{
int ret;
@ -866,7 +877,7 @@ int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
error_setg(&err,
"%s: VFIO device doesn't support device dirty tracking",
vbasedev->name);
return vfio_block_migration(vbasedev, err, errp);
goto add_blocker;
}
warn_report("%s: VFIO device doesn't support device dirty tracking",
@ -875,29 +886,31 @@ int vfio_migration_realize(VFIODevice *vbasedev, Error **errp)
ret = vfio_block_multiple_devices_migration(vbasedev, errp);
if (ret) {
return ret;
goto out_deinit;
}
if (vfio_viommu_preset(vbasedev)) {
error_setg(&err, "%s: Migration is currently not supported "
"with vIOMMU enabled", vbasedev->name);
return vfio_block_migration(vbasedev, err, errp);
goto add_blocker;
}
trace_vfio_migration_realize(vbasedev->name);
return 0;
add_blocker:
ret = vfio_block_migration(vbasedev, err, errp);
out_deinit:
if (ret) {
vfio_migration_deinit(vbasedev);
}
return ret;
}
void vfio_migration_exit(VFIODevice *vbasedev)
{
if (vbasedev->migration) {
VFIOMigration *migration = vbasedev->migration;
remove_migration_state_change_notifier(&migration->migration_state);
qemu_del_vm_change_state_handler(migration->vm_state);
unregister_savevm(VMSTATE_IF(vbasedev->dev), "vfio", vbasedev);
vfio_migration_free(vbasedev);
vfio_unblock_multiple_devices_migration();
vfio_migration_deinit(vbasedev);
}
if (vbasedev->migration_blocker) {

1
hw/vfio/pci.c
View File

@ -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;
}
}