Re: [PATCH v3 1/3] migration/multifd: Ensure we're not given a socket for file migration

[Peter Xu <peterx@redhat.com>]

On Fri, Mar 15, 2024 at 12:20:38AM -0300, Fabiano Rosas wrote:
> When doing migration using the fd: URI, QEMU will fetch the file
> descriptor passed in via the monitor at
> fd_start_outgoing|incoming_migration(), which means the checks at
> migration_channels_and_transport_compatible() happen too soon and we
> don't know at that point whether the FD refers to a plain file or a
> socket.
> 
> For this reason, we've been allowing a migration channel of type
> SOCKET_ADDRESS_TYPE_FD to pass the initial verifications in scenarios
> where the socket migration is not supported, such as with fd + multifd.
> 
> The commit decdc76772 ("migration/multifd: Add mapped-ram support to
> fd: URI") was supposed to add a second check prior to starting
> migration to make sure a socket fd is not passed instead of a file fd,
> but failed to do so.
> 
> Add the missing verification and update the comment explaining this
> situation which is currently incorrect.
> 
> Fixes: decdc76772 ("migration/multifd: Add mapped-ram support to fd: URI")
> Signed-off-by: Fabiano Rosas <farosas@suse.de>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu