[PATCH] Revert "virtio_console: fix order of fields cols and rows"

["Michael S. Tsirkin" <mst@redhat.com>]

This reverts commit 5326ab737a47278dbd16ed3ee7380b26c7056ddd.

The problem is that for a long time, the
Linux kernel used a different field order from what was specified in the
virtio spec. The kernel implementation was apparently merged around 2010,
while the virtio spec came in 2014, so when a previous version of this
patch series was being discussed here on this mailing list in 2020, it
was decided that QEMU should match the Linux implementation, and ideally,
the virtio spec should be changed.

There are about 15 years' worth
of kernel versions with the swapped field order, including the kernel
currently shipped in Debian stable. The effects of the swapped dimensions
can sometimes be quite annoying - e.g. if you have a terminal with
24 rows, this will be interpreted as 24 columns, and your shell may limit
line editing to this small space, most of which will be taken by your
prompt.

NB: the command structures really should move to the UAPI header so it
is easier to notice when a change is breaking the guest/host ABI.

Reported-by: Filip Hejsek <filip.hejsek@gmail.com>
Fixes: 5326ab737a47 ("virtio_console: fix order of fields cols and rows")
Cc: "Maximilian Immanuel Brandtner" <maxbr@linux.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/char/virtio_console.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 088182e54deb..216c5115637d 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1576,8 +1576,8 @@ static void handle_control_message(struct virtio_device *vdev,
 		break;
 	case VIRTIO_CONSOLE_RESIZE: {
 		struct {
-			__virtio16 cols;
 			__virtio16 rows;
+			__virtio16 cols;
 		} size;
 
 		if (!is_console_port(port))
-- 
MST