migration: Simplify qemu_save_device_state()

This function is used by both COLO and Xen.  Simplify it with two changes:

- Remove checks on qemu_savevm_se_iterable(): this is not needed as
  vmstate_save() also checks for "save_state() || vmsd" instead.  Here,
  save_setup() (or say, iterable states) should be mutual exclusive to
  "save_state() || vmsd" [*].

- Remove migrate_error_propagate(): both of the users are not using live
  migration framework, but raw vmstate operations.  Error propagation is
  only needed for query-migrate persistence.

[*] One tricky user is VFIO, who provided _both_ save_state() and
save_setup().  However VFIO mustn't have been used in these paths or it
means both COLO and Xen have ignored VFIO data instead (that is,
qemu_savevm_se_iterable() will return true for VFIO). Hence, this change is
safe.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Paul Durrant <paul@xen.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Tested-by: Lukas Straub <lukasstraub2@web.de>
Link: https://lore.kernel.org/qemu-devel/20260127185254.3954634-24-peterx@redhat.com
[commit msg: s/not needed for/only needed for]
Signed-off-by: Fabiano Rosas <farosas@suse.de>

diff --git a/migration/savevm.c b/migration/savevm.c
index 130b9764a7931bb4b149bdd32e0de108944cd2a2..b29272db3b68f0546faed301f09a0499c4dfaaa7 100644 (file)
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1897,13 +1897,8 @@ int qemu_save_device_state(QEMUFile *f)
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
         int ret;
 
-        if (qemu_savevm_se_iterable(se)) {
-            continue;
-        }
         ret = vmstate_save(f, se, NULL, &local_err);
         if (ret) {
-            migrate_error_propagate(migrate_get_current(),
-                                    error_copy(local_err));
             error_report_err(local_err);
             return ret;
         }