Commit 1f7aa42d authored by Amit Shah's avatar Amit Shah Committed by Rusty Russell

virtio: console: Add ability to hot-unplug ports

Remove port data; deregister from the hvc core if it's a console port.
Signed-off-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 7f5d810d
...@@ -783,6 +783,36 @@ static struct attribute_group port_attribute_group = { ...@@ -783,6 +783,36 @@ static struct attribute_group port_attribute_group = {
.attrs = port_sysfs_entries, .attrs = port_sysfs_entries,
}; };
/* Remove all port-specific data. */
static int remove_port(struct port *port)
{
spin_lock_irq(&port->portdev->ports_lock);
list_del(&port->list);
spin_unlock_irq(&port->portdev->ports_lock);
if (is_console_port(port)) {
spin_lock_irq(&pdrvdata_lock);
list_del(&port->cons.list);
spin_unlock_irq(&pdrvdata_lock);
hvc_remove(port->cons.hvc);
}
if (port->guest_connected)
send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
while (port->in_vq->vq_ops->detach_unused_buf(port->in_vq))
;
sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
device_destroy(pdrvdata.class, port->dev->devt);
cdev_del(&port->cdev);
discard_port_data(port);
kfree(port->name);
kfree(port);
return 0;
}
/* Any private messages that the Host and Guest want to share */ /* Any private messages that the Host and Guest want to share */
static void handle_control_message(struct ports_device *portdev, static void handle_control_message(struct ports_device *portdev,
struct port_buffer *buf) struct port_buffer *buf)
...@@ -854,6 +884,32 @@ static void handle_control_message(struct ports_device *portdev, ...@@ -854,6 +884,32 @@ static void handle_control_message(struct ports_device *portdev,
err); err);
break; break;
case VIRTIO_CONSOLE_PORT_REMOVE:
/*
* Hot unplug the port. We don't decrement nr_ports
* since we don't want to deal with extra complexities
* of using the lowest-available port id: We can just
* pick up the nr_ports number as the id and not have
* userspace send it to us. This helps us in two
* ways:
*
* - We don't need to have a 'port_id' field in the
* config space when a port is hot-added. This is a
* good thing as we might queue up multiple hotplug
* requests issued in our workqueue.
*
* - Another way to deal with this would have been to
* use a bitmap of the active ports and select the
* lowest non-active port from that map. That
* bloats the already tight config space and we
* would end up artificially limiting the
* max. number of ports to sizeof(bitmap). Right
* now we can support 2^32 ports (as the port id is
* stored in a u32 type).
*
*/
remove_port(port);
break;
} }
} }
...@@ -1078,11 +1134,16 @@ static void config_work_handler(struct work_struct *work) ...@@ -1078,11 +1134,16 @@ static void config_work_handler(struct work_struct *work)
/* /*
* Port 0 got hot-added. Since we already did all the * Port 0 got hot-added. Since we already did all the
* other initialisation for it, just tell the Host * other initialisation for it, just tell the Host
* that the port is ready. * that the port is ready if we find the port. In
* case the port was hot-removed earlier, we call
* add_port to add the port.
*/ */
struct port *port; struct port *port;
port = find_port_by_id(portdev, 0); port = find_port_by_id(portdev, 0);
if (!port)
add_port(portdev, 0);
else
send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1); send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
return; return;
} }
......
...@@ -41,6 +41,7 @@ struct virtio_console_control { ...@@ -41,6 +41,7 @@ struct virtio_console_control {
#define VIRTIO_CONSOLE_RESIZE 2 #define VIRTIO_CONSOLE_RESIZE 2
#define VIRTIO_CONSOLE_PORT_OPEN 3 #define VIRTIO_CONSOLE_PORT_OPEN 3
#define VIRTIO_CONSOLE_PORT_NAME 4 #define VIRTIO_CONSOLE_PORT_NAME 4
#define VIRTIO_CONSOLE_PORT_REMOVE 5
#ifdef __KERNEL__ #ifdef __KERNEL__
int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)); int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int));
......
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