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Commit 2b8f41d8 authored by Amit Shah's avatar Amit Shah Committed by Rusty Russell
Browse files

virtio: console: Add freeze and restore handlers to support S4 



Remove all vqs and associated buffers in the freeze callback which
prepares us to go into hibernation state.  On restore, re-create all the
vqs and populate the input vqs with buffers to get to the pre-hibernate
state.

Note: Any outstanding unconsumed buffers are discarded; which means
there's a possibility of data loss in case the host or the guest didn't
consume any data already present in the vqs.  This can be addressed in a
later patch series, perhaps in virtio common code.

Signed-off-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent a0e2dbfc

drivers/char/virtio_console.c

+58 −0
Original line number Diff line number Diff line
@@ -1844,6 +1844,60 @@ static unsigned int features[] = { 
	VIRTIO_CONSOLE_F_MULTIPORT,

};



#ifdef CONFIG_PM

static int virtcons_freeze(struct virtio_device *vdev)

{

	struct ports_device *portdev;

	struct port *port;



	portdev = vdev->priv;



	vdev->config->reset(vdev);



	cancel_work_sync(&portdev->control_work);

	remove_controlq_data(portdev);



	list_for_each_entry(port, &portdev->ports, list) {

		/*

		 * We'll ask the host later if the new invocation has

		 * the port opened or closed.

		 */

		port->host_connected = false;

		remove_port_data(port);

	}

	remove_vqs(portdev);



	return 0;

}



static int virtcons_restore(struct virtio_device *vdev)

{

	struct ports_device *portdev;

	struct port *port;

	int ret;



	portdev = vdev->priv;



	ret = init_vqs(portdev);

	if (ret)

		return ret;



	if (use_multiport(portdev))

		fill_queue(portdev->c_ivq, &portdev->cvq_lock);



	list_for_each_entry(port, &portdev->ports, list) {

		port->in_vq = portdev->in_vqs[port->id];

		port->out_vq = portdev->out_vqs[port->id];



		fill_queue(port->in_vq, &port->inbuf_lock);



		/* Get port open/close status on the host */

		send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);

	}

	return 0;

}

#endif



static struct virtio_driver virtio_console = {

	.feature_table = features,

	.feature_table_size = ARRAY_SIZE(features),
@@ -1853,6 +1907,10 @@ static struct virtio_driver virtio_console = { 
	.probe =	virtcons_probe,

	.remove =	virtcons_remove,

	.config_changed = config_intr,

#ifdef CONFIG_PM

	.freeze =	virtcons_freeze,

	.restore =	virtcons_restore,

#endif

};



static int __init init(void)