docs/devel/migration.rst: Document the file transport

When adding the support for file migration with the file: transport,
we missed adding documentation for it.

Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240220224138.24759-2-farosas@suse.de
Signed-off-by: Peter Xu <peterx@redhat.com>

diff --git a/docs/devel/migration/main.rst b/docs/devel/migration/main.rst
index 331252a92c4c3418f9b70724dc296d07fcc49e5f..8024275d6d3e4460ce7ae31a5d944eec8c8150cb 100644 (file)
--- a/docs/devel/migration/main.rst
+++ b/docs/devel/migration/main.rst
@@ -41,6 +41,10 @@ over any transport.
 - exec migration: do the migration using the stdin/stdout through a process.
 - fd migration: do the migration using a file descriptor that is
   passed to QEMU.  QEMU doesn't care how this file descriptor is opened.
+- file migration: do the migration using a file that is passed to QEMU
+  by path. A file offset option is supported to allow a management
+  application to add its own metadata to the start of the file without
+  QEMU interference.
 
 In addition, support is included for migration using RDMA, which
 transports the page data using ``RDMA``, where the hardware takes care of