commit cf53efbbda2e45aad2f54b797f2ebfa001aad629
author Avihai Horon <avihaih@nvidia.com> Wed Jun 21 14:11:58 2023 +0300
committer Cédric Le Goater <clg@redhat.com> Fri Jun 30 06:02:51 2023 +0200
tree 3ac1e41533d4a09de52f107c6c33ab07c42b0081
parent 7e6a5c730be49bd113a552cd2c4e4b91abfdd4fb

vfio/migration: Refactor vfio_save_block() to return saved data size

Refactor vfio_save_block() to return the size of saved data on success
and -errno on error.

This will be used in next patch to implement VFIO migration pre-copy
support.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Tested-by: YangHang Liu <yanghliu@redhat.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/vfio/migration.c

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 6b58ddd..235978f 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -241,8 +241,8 @@
     return 0;
 }
 
-/* Returns 1 if end-of-stream is reached, 0 if more data and -errno if error */
-static int vfio_save_block(QEMUFile *f, VFIOMigration *migration)
+/* Returns the size of saved data on success and -errno on error */
+static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration)
 {
     ssize_t data_size;
 
@@ -252,7 +252,7 @@
         return -errno;
     }
     if (data_size == 0) {
-        return 1;
+        return 0;
     }
 
     qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
@@ -262,7 +262,7 @@
 
     trace_vfio_save_block(migration->vbasedev->name, data_size);
 
-    return qemu_file_get_error(f);
+    return qemu_file_get_error(f) ?: data_size;
 }
 
 /* ---------------------------------------------------------------------- */
@@ -335,6 +335,7 @@
 static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
 {
     VFIODevice *vbasedev = opaque;
+    ssize_t data_size;
     int ret;
 
     /* We reach here with device state STOP only */
@@ -345,11 +346,11 @@
     }
 
     do {
-        ret = vfio_save_block(f, vbasedev->migration);
-        if (ret < 0) {
-            return ret;
+        data_size = vfio_save_block(f, vbasedev->migration);
+        if (data_size < 0) {
+            return data_size;
         }
-    } while (!ret);
+    } while (data_size);
 
     qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
     ret = qemu_file_get_error(f);