virtio: console: Add debugfs files for each port to expose debug info
This is helpful in examining ports' state.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 9f20fda..2a04daa 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -17,6 +17,7 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/cdev.h>
+#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fs.h>
@@ -43,6 +44,9 @@
/* Used for registering chardevs */
struct class *class;
+ /* Used for exporting per-port information to debugfs */
+ struct dentry *debugfs_dir;
+
/* Number of devices this driver is handling */
unsigned int index;
@@ -158,6 +162,9 @@
/* The IO vqs for this port */
struct virtqueue *in_vq, *out_vq;
+ /* File in the debugfs directory that exposes this port's information */
+ struct dentry *debugfs_file;
+
/*
* The entries in this struct will be valid if this port is
* hooked up to an hvc console
@@ -783,6 +790,49 @@
.attrs = port_sysfs_entries,
};
+static int debugfs_open(struct inode *inode, struct file *filp)
+{
+ filp->private_data = inode->i_private;
+ return 0;
+}
+
+static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
+ size_t count, loff_t *offp)
+{
+ struct port *port;
+ char *buf;
+ ssize_t ret, out_offset, out_count;
+
+ out_count = 1024;
+ buf = kmalloc(out_count, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ port = filp->private_data;
+ out_offset = 0;
+ out_offset += snprintf(buf + out_offset, out_count,
+ "name: %s\n", port->name ? port->name : "");
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "guest_connected: %d\n", port->guest_connected);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "host_connected: %d\n", port->host_connected);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "is_console: %s\n",
+ is_console_port(port) ? "yes" : "no");
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "console_vtermno: %u\n", port->cons.vtermno);
+
+ ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);
+ kfree(buf);
+ return ret;
+}
+
+static const struct file_operations port_debugfs_ops = {
+ .owner = THIS_MODULE,
+ .open = debugfs_open,
+ .read = debugfs_read,
+};
+
/* Remove all port-specific data. */
static int remove_port(struct port *port)
{
@@ -809,6 +859,8 @@
discard_port_data(port);
kfree(port->name);
+ debugfs_remove(port->debugfs_file);
+
kfree(port);
return 0;
}
@@ -1021,6 +1073,7 @@
static int add_port(struct ports_device *portdev, u32 id)
{
+ char debugfs_name[16];
struct port *port;
struct port_buffer *inbuf;
dev_t devt;
@@ -1096,6 +1149,18 @@
*/
send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
+ if (pdrvdata.debugfs_dir) {
+ /*
+ * Finally, create the debugfs file that we can use to
+ * inspect a port's state at any time
+ */
+ sprintf(debugfs_name, "vport%up%u",
+ port->portdev->drv_index, id);
+ port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
+ pdrvdata.debugfs_dir,
+ port,
+ &port_debugfs_ops);
+ }
return 0;
free_inbuf:
@@ -1406,6 +1471,12 @@
pr_err("Error %d creating virtio-ports class\n", err);
return err;
}
+
+ pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
+ if (!pdrvdata.debugfs_dir) {
+ pr_warning("Error %ld creating debugfs dir for virtio-ports\n",
+ PTR_ERR(pdrvdata.debugfs_dir));
+ }
INIT_LIST_HEAD(&pdrvdata.consoles);
return register_virtio_driver(&virtio_console);