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path: root/drivers/char/virtio_console.c
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Diffstat (limited to 'drivers/char/virtio_console.c')
-rw-r--r--drivers/char/virtio_console.c120
1 files changed, 79 insertions, 41 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index fb68b129537..4ca181f1378 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -19,8 +19,10 @@
*/
#include <linux/cdev.h>
#include <linux/debugfs.h>
+#include <linux/completion.h>
#include <linux/device.h>
#include <linux/err.h>
+#include <linux/freezer.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/list.h>
@@ -73,6 +75,7 @@ struct ports_driver_data {
static struct ports_driver_data pdrvdata;
DEFINE_SPINLOCK(pdrvdata_lock);
+DECLARE_COMPLETION(early_console_added);
/* This struct holds information that's relevant only for console ports */
struct console {
@@ -151,6 +154,10 @@ struct ports_device {
int chr_major;
};
+struct port_stats {
+ unsigned long bytes_sent, bytes_received, bytes_discarded;
+};
+
/* This struct holds the per-port data */
struct port {
/* Next port in the list, head is in the ports_device */
@@ -179,6 +186,13 @@ struct port {
struct dentry *debugfs_file;
/*
+ * Keep count of the bytes sent, received and discarded for
+ * this port for accounting and debugging purposes. These
+ * counts are not reset across port open / close events.
+ */
+ struct port_stats stats;
+
+ /*
* The entries in this struct will be valid if this port is
* hooked up to an hvc console
*/
@@ -347,17 +361,19 @@ fail:
}
/* Callers should take appropriate locks */
-static void *get_inbuf(struct port *port)
+static struct port_buffer *get_inbuf(struct port *port)
{
struct port_buffer *buf;
- struct virtqueue *vq;
unsigned int len;
- vq = port->in_vq;
- buf = virtqueue_get_buf(vq, &len);
+ if (port->inbuf)
+ return port->inbuf;
+
+ buf = virtqueue_get_buf(port->in_vq, &len);
if (buf) {
buf->len = len;
buf->offset = 0;
+ port->stats.bytes_received += len;
}
return buf;
}
@@ -384,32 +400,27 @@ static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
static void discard_port_data(struct port *port)
{
struct port_buffer *buf;
- struct virtqueue *vq;
- unsigned int len;
- int ret;
+ unsigned int err;
if (!port->portdev) {
/* Device has been unplugged. vqs are already gone. */
return;
}
- vq = port->in_vq;
- if (port->inbuf)
- buf = port->inbuf;
- else
- buf = virtqueue_get_buf(vq, &len);
+ buf = get_inbuf(port);
- ret = 0;
+ err = 0;
while (buf) {
- if (add_inbuf(vq, buf) < 0) {
- ret++;
+ port->stats.bytes_discarded += buf->len - buf->offset;
+ if (add_inbuf(port->in_vq, buf) < 0) {
+ err++;
free_buf(buf);
}
- buf = virtqueue_get_buf(vq, &len);
+ port->inbuf = NULL;
+ buf = get_inbuf(port);
}
- port->inbuf = NULL;
- if (ret)
+ if (err)
dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
- ret);
+ err);
}
static bool port_has_data(struct port *port)
@@ -417,18 +428,12 @@ static bool port_has_data(struct port *port)
unsigned long flags;
bool ret;
+ ret = false;
spin_lock_irqsave(&port->inbuf_lock, flags);
- if (port->inbuf) {
- ret = true;
- goto out;
- }
port->inbuf = get_inbuf(port);
- if (port->inbuf) {
+ if (port->inbuf)
ret = true;
- goto out;
- }
- ret = false;
-out:
+
spin_unlock_irqrestore(&port->inbuf_lock, flags);
return ret;
}
@@ -529,6 +534,8 @@ static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
cpu_relax();
done:
spin_unlock_irqrestore(&port->outvq_lock, flags);
+
+ port->stats.bytes_sent += in_count;
/*
* We're expected to return the amount of data we wrote -- all
* of it
@@ -633,8 +640,8 @@ static ssize_t port_fops_read(struct file *filp, char __user *ubuf,
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
- ret = wait_event_interruptible(port->waitqueue,
- !will_read_block(port));
+ ret = wait_event_freezable(port->waitqueue,
+ !will_read_block(port));
if (ret < 0)
return ret;
}
@@ -677,8 +684,8 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
if (nonblock)
return -EAGAIN;
- ret = wait_event_interruptible(port->waitqueue,
- !will_write_block(port));
+ ret = wait_event_freezable(port->waitqueue,
+ !will_write_block(port));
if (ret < 0)
return ret;
}
@@ -1059,6 +1066,14 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf,
out_offset += snprintf(buf + out_offset, out_count - out_offset,
"outvq_full: %d\n", port->outvq_full);
out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "bytes_sent: %lu\n", port->stats.bytes_sent);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "bytes_received: %lu\n",
+ port->stats.bytes_received);
+ out_offset += snprintf(buf + out_offset, out_count - out_offset,
+ "bytes_discarded: %lu\n",
+ port->stats.bytes_discarded);
+ 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,
@@ -1143,6 +1158,7 @@ static int add_port(struct ports_device *portdev, u32 id)
port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
port->host_connected = port->guest_connected = false;
+ port->stats = (struct port_stats) { 0 };
port->outvq_full = false;
@@ -1352,6 +1368,7 @@ static void handle_control_message(struct ports_device *portdev,
break;
init_port_console(port);
+ complete(&early_console_added);
/*
* Could remove the port here in case init fails - but
* have to notify the host first.
@@ -1394,6 +1411,13 @@ static void handle_control_message(struct ports_device *portdev,
break;
case VIRTIO_CONSOLE_PORT_NAME:
/*
+ * If we woke up after hibernation, we can get this
+ * again. Skip it in that case.
+ */
+ if (port->name)
+ break;
+
+ /*
* Skip the size of the header and the cpkt to get the size
* of the name that was sent
*/
@@ -1481,8 +1505,7 @@ static void in_intr(struct virtqueue *vq)
return;
spin_lock_irqsave(&port->inbuf_lock, flags);
- if (!port->inbuf)
- port->inbuf = get_inbuf(port);
+ port->inbuf = get_inbuf(port);
/*
* Don't queue up data when port is closed. This condition
@@ -1563,7 +1586,7 @@ static int init_vqs(struct ports_device *portdev)
portdev->out_vqs = kmalloc(nr_ports * sizeof(struct virtqueue *),
GFP_KERNEL);
if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
- !portdev->out_vqs) {
+ !portdev->out_vqs) {
err = -ENOMEM;
goto free;
}
@@ -1648,6 +1671,10 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
struct ports_device *portdev;
int err;
bool multiport;
+ bool early = early_put_chars != NULL;
+
+ /* Ensure to read early_put_chars now */
+ barrier();
portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
if (!portdev) {
@@ -1675,13 +1702,11 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
multiport = false;
portdev->config.max_nr_ports = 1;
- if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
+ if (virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
+ offsetof(struct virtio_console_config,
+ max_nr_ports),
+ &portdev->config.max_nr_ports) == 0)
multiport = true;
- vdev->config->get(vdev, offsetof(struct virtio_console_config,
- max_nr_ports),
- &portdev->config.max_nr_ports,
- sizeof(portdev->config.max_nr_ports));
- }
err = init_vqs(portdev);
if (err < 0) {
@@ -1719,6 +1744,19 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
VIRTIO_CONSOLE_DEVICE_READY, 1);
+
+ /*
+ * If there was an early virtio console, assume that there are no
+ * other consoles. We need to wait until the hvc_alloc matches the
+ * hvc_instantiate, otherwise tty_open will complain, resulting in
+ * a "Warning: unable to open an initial console" boot failure.
+ * Without multiport this is done in add_port above. With multiport
+ * this might take some host<->guest communication - thus we have to
+ * wait.
+ */
+ if (multiport && early)
+ wait_for_completion(&early_console_added);
+
return 0;
free_vqs:
generated by cgit v1.2.3-70-g09d2 (git 2.51.2) at 2025-11-04 08:05:44 +0000