diff mbox series

[v2,3/3] vfio/migration: Add a note about migration rate limiting

Message ID 20240304105339.20713-4-avihaih@nvidia.com (mailing list archive)
State New, archived
Headers show
Series migration: Don't serialize devices in qemu_savevm_state_iterate() | expand

Commit Message

Avihai Horon March 4, 2024, 10:53 a.m. UTC 
VFIO migration buffer size is currently limited to 1MB. Therefore, there
is no need to check if migration rate exceeded, as in the worst case it
will exceed by only 1MB.

However, if the buffer size is later changed to a bigger value,
vfio_save_iterate() should enforce migration rate (similar to migration
RAM code).

Add a note about this in vfio_save_iterate() to serve as a reminder.

Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Avihai Horon <avihaih@nvidia.com>
---
 hw/vfio/migration.c | 6 ++++++
 1 file changed, 6 insertions(+)
diff mbox series

Patch

diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 0af783a5892..f82dcabc49a 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -505,6 +505,12 @@  static bool vfio_is_active_iterate(void *opaque)
     return vfio_device_state_is_precopy(vbasedev);
 }
 
+/*
+ * Note about migration rate limiting: VFIO migration buffer size is currently
+ * limited to 1MB, so there is no need to check if migration rate exceeded (as
+ * in the worst case it will exceed by 1MB). However, if the buffer size is
+ * later changed to a bigger value, migration rate should be enforced here.
+ */
 static int vfio_save_iterate(QEMUFile *f, void *opaque)
 {
     VFIODevice *vbasedev = opaque;