From: Avihai Horon Date: Mon, 4 Mar 2024 10:53:39 +0000 (+0200) Subject: vfio/migration: Add a note about migration rate limiting X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ff64e0ba817d79968bffa88d205397abf05cc6e8;p=qemu.git vfio/migration: Add a note about migration rate limiting 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 Signed-off-by: Avihai Horon Reviewed-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240304105339.20713-4-avihaih@nvidia.com Signed-off-by: Peter Xu --- diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index 0af783a589..f82dcabc49 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;