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: Amit Shah <amit.shah@xxxxxxxxxx>
---
drivers/char/virtio_console.c | 71 +++++++++++++++++++++++++++++++++++++++++
1 files changed, 71 insertions(+), 0 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index a7dfd02..9648cea 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -25,6 +25,7 @@
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/list.h>
+#include <linux/pm.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
@@ -1801,6 +1802,72 @@ 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;
+ struct port_buffer *buf;
+ unsigned int len;
+
+ portdev = vdev->priv;
+
+ if (use_multiport(portdev)) {
+ while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
+ free_buf(buf);
+
+ while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
+ free_buf(buf);
+ }
+ 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;
+ discard_port_data(port);
+ reclaim_consumed_buffers(port);
+
+ while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
+ free_buf(buf);
+ }
+ portdev->vdev->config->del_vqs(portdev->vdev);
+ kfree(portdev->in_vqs);
+ kfree(portdev->out_vqs);
+
+ 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);
+
+ /* XXX: Should this be done in 'complete' instead of 'restore'? */
+ /* 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),
@@ -1810,6 +1877,10 @@ 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)
--
1.7.6
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