From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>

Since device state transfer via multifd channels requires multifd
channels with packets and is currently not compatible with multifd
compression add an appropriate query function so device can learn
whether it can actually make use of it.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/1ff0d98b85f470e5a33687406e877583b8fab74e.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 include/migration/misc.h         | 1 +
 migration/multifd-device-state.c | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/include/migration/misc.h b/include/migration/misc.h
index bd3b725fa0b7efc4551aa19d2ac540f24bde4763..273ebfca6256265507cd6aa28a104a3db1ac106b 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -121,5 +121,6 @@ bool migrate_uri_parse(const char *uri, MigrationChannel **channel,
 /* migration/multifd-device-state.c */
 bool multifd_queue_device_state(char *idstr, uint32_t instance_id,
                                 char *data, size_t len);
+bool multifd_device_state_supported(void);
 
 #endif
diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c
index 64d8ca180167b09abf13c9302326404be236717e..3097ffa31025971bb9b893c53dad352d517148d9 100644
--- a/migration/multifd-device-state.c
+++ b/migration/multifd-device-state.c
@@ -13,6 +13,7 @@
 #include "qemu/lockable.h"
 #include "migration/misc.h"
 #include "multifd.h"
+#include "options.h"
 
 static struct {
     QemuMutex queue_job_mutex;
@@ -111,3 +112,9 @@ bool multifd_queue_device_state(char *idstr, uint32_t instance_id,
 
     return true;
 }
+
+bool multifd_device_state_supported(void)
+{
+    return migrate_multifd() && !migrate_mapped_ram() &&
+        migrate_multifd_compression() == MULTIFD_COMPRESSION_NONE;
+}
-- 
2.48.1