[RFC PATCH 01/13] vfio/migration: put together checks of migration initialization conditions

[Lei Rao <lei.rao@intel.com>]

Current VFIO live migration initialization code is tightly coupled with
local migration region handling. It is necessary to decouple it to
facilitate the introduction of a generic VFIO live migration framework so
that other approaches can be possible besides the In-Band approach.

This patch puts various checks of migration initialization conditions into
one function vfio_migration_check().

Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@intel.com>
---
 hw/vfio/migration.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index a6ad1f8945..770f535e81 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -787,6 +787,21 @@ static void vfio_migration_exit(VFIODevice *vbasedev)
     vbasedev->migration = NULL;
 }
 
+static int vfio_migration_check(VFIODevice *vbasedev)
+{
+    VFIOContainer *container = vbasedev->group->container;
+
+    if (!vbasedev->enable_migration || !container->dirty_pages_supported) {
+        return -EINVAL;
+    }
+
+    if (!vbasedev->ops->vfio_get_object) {
+        return -EINVAL;
+    }
+
+    return 0;
+}
+
 static int vfio_migration_init(VFIODevice *vbasedev,
                                struct vfio_region_info *info)
 {
@@ -796,10 +811,6 @@ static int vfio_migration_init(VFIODevice *vbasedev,
     char id[256] = "";
     g_autofree char *path = NULL, *oid = NULL;
 
-    if (!vbasedev->ops->vfio_get_object) {
-        return -EINVAL;
-    }
-
     obj = vbasedev->ops->vfio_get_object(vbasedev);
     if (!obj) {
         return -EINVAL;
@@ -857,11 +868,11 @@ int64_t vfio_mig_bytes_transferred(void)
 
 int vfio_migration_probe(VFIODevice *vbasedev, Error **errp)
 {
-    VFIOContainer *container = vbasedev->group->container;
     struct vfio_region_info *info = NULL;
     int ret = -ENOTSUP;
 
-    if (!vbasedev->enable_migration || !container->dirty_pages_supported) {
+    ret = vfio_migration_check(vbasedev);
+    if (ret) {
         goto add_blocker;
     }
 
-- 
2.32.0