virtio_console: support console resizing

this patch uses the new hvc callback hvc_resize to set the window size
which allows to change the tty size of hvc_console via a hvc_resize
function.

I have added a new feature bit VIRTIO_CONSOLE_F_SIZE. The driver will
change the window size on tty open and via the config_changed callback
of the transport. Currently lguest and kvm_s390 have not implemented this
callback, but the callback can be implemented at a later point in time.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h
index 19a0da0dba41..7615ffcdd555 100644
--- a/include/linux/virtio_console.h
+++ b/include/linux/virtio_console.h
@@ -7,6 +7,17 @@
 /* The ID for virtio console */
 #define VIRTIO_ID_CONSOLE       3
 
+/* Feature bits */
+#define VIRTIO_CONSOLE_F_SIZE   0       /* Does host provide console size? */
+
+struct virtio_console_config {
+        /* colums of the screens */
+        __u16 cols;
+        /* rows of the screens */
+        __u16 rows;
+} __attribute__((packed));
+
+
 #ifdef __KERNEL__
 int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int));
 #endif /* __KERNEL__ */