Add a bit more spice by adding support for multiple console ports.
This introduces a new feature: VIRTIO_CONSOLE_F_MULTIPORT. If a
willing host is found, this support is switched on and a small
'header' is transmitted along with every data packet that's sent
in either direction.
This header stores the port number the data is meant for, along
with a few other fields which will be used for other features
to support generic ports.
The interface is of a simple char device with open, read, write,
poll and close calls, eg:
fd = open("/dev/vcon2", O_RDWR);
ret = read(fd, buf, 100);
ret = write(fd, string, strlen(string));
Signed-off-by: Amit Shah <[email protected]>
---
drivers/char/virtio_console.c | 730 ++++++++++++++++++++++++++++++++++------
include/linux/virtio_console.h | 44 +++-
2 files changed, 675 insertions(+), 99 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index e97188e..4119c37 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -10,6 +10,7 @@
:*/
/* Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation
+ * Copyright (C) 2009, Amit Shah, Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -25,12 +26,20 @@
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+
+#include <linux/cdev.h>
+#include <linux/device.h>
#include <linux/err.h>
+#include <linux/fs.h>
#include <linux/init.h>
#include <linux/list.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/virtio.h>
#include <linux/virtio_console.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
#include "hvc_console.h"
struct virtio_console_struct {
@@ -41,20 +50,15 @@ struct virtio_console_struct {
struct work_struct rx_work;
struct work_struct tx_work;
- /* Buffer management */
+ struct list_head port_head;
struct list_head unused_read_head;
struct list_head unused_write_head;
- struct list_head readbuf_head;
/* To protect the list of unused write buffers and the out_vq */
spinlock_t write_list_lock;
- /*
- * To protect the readbuf_head list. Has to be a spinlock
- * because it can be called from interrupt context
- * (get_char())
- */
- spinlock_t readbuf_list_lock;
+ /* The current config space is stored here */
+ struct virtio_console_config config;
/*D:340
* These represent our input and output console queues,
@@ -63,11 +67,22 @@ struct virtio_console_struct {
struct virtqueue *in_vq, *out_vq;
struct virtio_device *vdev;
- /* The hvc device */
- struct hvc_struct *hvc;
+ struct class *class;
+
+ /*
+ * This is used to keep track of the number of hvc consoles
+ * spawned. This number is given as first argument to
+ * hvc_alloc(). To correctly map an initial console spawned
+ * via hvc_instantiate to the console being hooked up via
+ * hvc_alloc, we need to pass the same vtermno.
+ *
+ * We also just assume the first console being initialised was
+ * the first one that got used as the initial console.
+ */
+ unsigned int hvc_vtermno;
};
-/* This struct holds individual buffers received from the host */
+/* This struct holds individual buffers received for each port */
struct virtio_console_port_buffer {
struct list_head list;
@@ -79,76 +94,206 @@ struct virtio_console_port_buffer {
size_t offset;
};
+/* This struct holds the per-port data */
+struct virtio_console_port {
+ /* Next port in the list, head is in the virtio_console_struct */
+ struct list_head list;
+
+ /* Pointer to the virtio_console device */
+ struct virtio_console_struct *vcon;
+
+ /* Buffer management */
+ struct list_head readbuf_head;
+
+ /*
+ * To protect the readbuf_head list. Has to be a spinlock
+ * because it can be called from interrupt context
+ * (get_char())
+ */
+ spinlock_t readbuf_list_lock;
+
+ /* A waitqueue for poll() or blocking read operations */
+ wait_queue_head_t waitqueue;
+
+ /* Each port associates with a separate char device */
+ struct cdev cdev;
+ struct device *dev;
+
+ /* The hvc device, if this port is associated with a console */
+ struct hvc_struct *hvc;
+
+ /* The 'name' of the port that we expose via sysfs properties */
+ char *name;
+
+ /* The 'id' to identify the port with the Host */
+ u32 id;
+
+ /*
+ * If this port is a console port, this number identifies the
+ * number that we used to register with hvc in
+ * hvc_instantiate() and hvc_alloc().
+ */
+ u32 vtermno;
+
+ /* Is the host device open */
+ bool host_connected;
+};
+
struct virtio_console_struct virtconsole;
-/*D:310
- * The put_chars() callback is pretty straightforward.
- *
- * We turn the characters into a scatter-gather list, add it to the output
- * queue and then kick the Host.
- *
- * If the data to be output spans more than a page, it's split into
- * page-sized buffers and then individual buffers are pushed to the Host.
- */
-static int put_chars(u32 vtermno, const char *in_buf, int in_count)
+static struct virtio_console_port *get_port_from_vtermno(u32 vtermno)
+{
+ struct virtio_console_port *port;
+
+ list_for_each_entry(port, &virtconsole.port_head, list) {
+ if (port->hvc && port->vtermno == vtermno)
+ return port;
+ }
+ return NULL;
+}
+
+static struct virtio_console_port *get_port_from_id(u32 id)
+{
+ struct virtio_console_port *port;
+
+ list_for_each_entry(port, &virtconsole.port_head, list) {
+ if (port->id == id)
+ return port;
+ }
+ return NULL;
+}
+
+static struct virtio_console_port *get_port_from_hvc(struct hvc_struct *hvc)
+{
+ struct virtio_console_port *port;
+
+ list_for_each_entry(port, &virtconsole.port_head, list) {
+ if (port->hvc == hvc)
+ return port;
+ }
+ return NULL;
+}
+
+static int get_id_from_port(struct virtio_console_port *port)
+{
+ return port->id;
+}
+
+static bool is_console_port(struct virtio_console_port *port)
+{
+ if (port->hvc)
+ return true;
+ return false;
+}
+
+static inline bool use_multiport(struct virtio_console_struct *vcon)
+{
+ /*
+ * This condition can be true when put_chars is called from
+ * early_init
+ */
+ if (!vcon->vdev)
+ return 0;
+ return vcon->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+}
+
+static inline bool is_control(u32 flags)
+{
+ return flags & VIRTIO_CONSOLE_ID_CONTROL;
+}
+
+static ssize_t send_buf(struct virtio_console_port *port,
+ const char *in_buf, size_t in_count,
+ u32 flags, bool from_user)
{
struct virtqueue *out_vq;
struct virtio_console_port_buffer *buf, *buf2;
struct scatterlist sg[1];
+ struct virtio_console_header header;
size_t in_offset, copy_size;
ssize_t ret;
+ unsigned int header_len;
if (!in_count)
return 0;
- out_vq = virtconsole.out_vq;
-
+ out_vq = port->vcon->out_vq;
+ /*
+ * We should not send control messages to a host that won't
+ * understand them
+ */
+ if (!use_multiport(port->vcon) && is_control(flags))
+ return 0;
+ header_len = 0;
+ if (use_multiport(port->vcon)) {
+ header.id = get_id_from_port(port);
+ header.flags = flags;
+ header.size = in_count;
+ header_len = sizeof(header);
+ }
in_offset = 0; /* offset in the user buffer */
while (in_count - in_offset) {
- copy_size = min(in_count - in_offset, PAGE_SIZE);
+ copy_size = min(in_count - in_offset + header_len, PAGE_SIZE);
- spin_lock(&virtconsole.write_list_lock);
+ spin_lock(&port->vcon->write_list_lock);
list_for_each_entry_safe(buf, buf2,
- &virtconsole.unused_write_head,
+ &port->vcon->unused_write_head,
list) {
list_del(&buf->list);
break;
}
- spin_unlock(&virtconsole.write_list_lock);
+ spin_unlock(&port->vcon->write_list_lock);
if (!buf)
break;
- /*
- * Since we're not sure when the host will actually
- * consume the data and tell us about it, we have
- * to copy the data here in case the caller
- * frees the in_buf
- */
- memcpy(buf->buf, in_buf + in_offset, copy_size);
-
- buf->len = copy_size;
+ if (header_len) {
+ memcpy(buf->buf, &header, header_len);
+ copy_size -= header_len;
+ }
+ if (from_user) {
+ ret = copy_from_user(buf->buf + header_len,
+ in_buf + in_offset, copy_size);
+ } else {
+ /*
+ * Since we're not sure when the host will actually
+ * consume the data and tell us about it, we have
+ * to copy the data here in case the caller
+ * frees the in_buf
+ */
+ memcpy(buf->buf + header_len,
+ in_buf + in_offset, copy_size);
+ ret = 0; /* Emulate copy_from_user behaviour */
+ }
+ buf->len = header_len + copy_size - ret;
sg_init_one(sg, buf->buf, buf->len);
- spin_lock(&virtconsole.write_list_lock);
+ spin_lock(&port->vcon->write_list_lock);
ret = out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, buf);
- spin_unlock(&virtconsole.write_list_lock);
+ spin_unlock(&port->vcon->write_list_lock);
if (ret < 0) {
memset(buf->buf, 0, buf->len);
- spin_lock(&virtconsole.write_list_lock);
+ spin_lock(&port->vcon->write_list_lock);
list_add_tail(&buf->list,
- &virtconsole.unused_write_head);
- spin_unlock(&virtconsole.write_list_lock);
+ &port->vcon->unused_write_head);
+ spin_unlock(&port->vcon->write_list_lock);
break;
}
- in_offset += buf->len;
+ in_offset += buf->len - header_len;
+ /*
+ * Only send size with the first buffer. This way
+ * userspace can find out a continuous stream of data
+ * belonging to one write request and consume it
+ * appropriately
+ */
+ header.size = 0;
/* No space left in the vq anyway */
if (!ret)
break;
}
/* Tell Host to go! */
- spin_lock(&virtconsole.write_list_lock);
+ spin_lock(&port->vcon->write_list_lock);
out_vq->vq_ops->kick(out_vq);
- spin_unlock(&virtconsole.write_list_lock);
+ spin_unlock(&port->vcon->write_list_lock);
/* We're expected to return the amount of data we wrote */
return in_offset;
@@ -158,7 +303,8 @@ static int put_chars(u32 vtermno, const char *in_buf, int
in_count)
* Give out the data that's requested from the buffers that we have
* queued up.
*/
-static ssize_t fill_readbuf(char *out_buf, size_t out_count)
+static ssize_t fill_readbuf(struct virtio_console_port *port,
+ char *out_buf, size_t out_count, bool to_user)
{
struct virtio_console_port_buffer *buf, *buf2;
ssize_t out_offset, ret;
@@ -168,26 +314,38 @@ static ssize_t fill_readbuf(char *out_buf, size_t
out_count)
* Not taking the port->readbuf_list_lock here relying on the
* fact that buffers are taken out from the list only in this
* function so buf2 should be available all the time.
+ *
+ * Also, copy_to_user() might sleep.
*/
- list_for_each_entry_safe(buf, buf2, &virtconsole.readbuf_head, list) {
+ list_for_each_entry_safe(buf, buf2, &port->readbuf_head, list) {
size_t copy_size;
copy_size = out_count;
if (copy_size > buf->len - buf->offset)
copy_size = buf->len - buf->offset;
- memcpy(out_buf + out_offset, buf->buf + buf->offset, copy_size);
+ if (to_user) {
+ ret = copy_to_user(out_buf + out_offset,
+ buf->buf + buf->offset,
+ copy_size);
+ /* FIXME: Deal with ret != 0 */
+ } else {
+ memcpy(out_buf + out_offset,
+ buf->buf + buf->offset,
+ copy_size);
+ ret = 0; /* Emulate copy_to_user behaviour */
+ }
/* Return the number of bytes actually copied */
- ret = copy_size;
+ ret = copy_size - ret;
buf->offset += ret;
out_offset += ret;
out_count -= ret;
if (buf->len - buf->offset == 0) {
- spin_lock(&virtconsole.readbuf_list_lock);
+ spin_lock(&port->readbuf_list_lock);
list_del(&buf->list);
- spin_unlock(&virtconsole.readbuf_list_lock);
+ spin_unlock(&port->readbuf_list_lock);
kfree(buf->buf);
kfree(buf);
}
@@ -197,6 +355,156 @@ static ssize_t fill_readbuf(char *out_buf, size_t
out_count)
return out_offset;
}
+/* The condition that must be true for polling to end */
+static bool wait_is_over(struct virtio_console_port *port)
+{
+ return !list_empty(&port->readbuf_head) || !port->host_connected;
+}
+
+static ssize_t virtconsole_read(struct file *filp, char __user *ubuf,
+ size_t count, loff_t *offp)
+{
+ struct virtio_console_port *port;
+ ssize_t ret;
+
+ port = filp->private_data;
+
+ if (list_empty(&port->readbuf_head)) {
+ /*
+ * If nothing's connected on the host just return 0 in
+ * case of list_empty; this tells the userspace app
+ * that there's no connection
+ */
+ if (!port->host_connected)
+ return 0;
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(port->waitqueue,
+ wait_is_over(port));
+ if (ret < 0)
+ return ret;
+ }
+ /*
+ * We could've received a disconnection message while we were
+ * waiting for more data.
+ *
+ * This check is not clubbed in the if() statement above as we
+ * might receive some data as well as the host could get
+ * disconnected after we got woken up from our wait. So we
+ * really want to give off whatever data we have and only then
+ * check for host_connected
+ */
+ if (list_empty(&port->readbuf_head) && !port->host_connected)
+ return 0;
+
+ return fill_readbuf(port, ubuf, count, true);
+}
+
+static ssize_t virtconsole_write(struct file *filp, const char __user *ubuf,
+ size_t count, loff_t *offp)
+{
+ struct virtio_console_port *port;
+
+ port = filp->private_data;
+
+ return send_buf(port, ubuf, count, 0, true);
+}
+
+static unsigned int virtconsole_poll(struct file *filp, poll_table *wait)
+{
+ struct virtio_console_port *port;
+ unsigned int ret;
+
+ port = filp->private_data;
+ poll_wait(filp, &port->waitqueue, wait);
+
+ ret = 0;
+ if (!list_empty(&port->readbuf_head))
+ ret |= POLLIN | POLLRDNORM;
+ if (port->host_connected)
+ ret |= POLLOUT;
+ if (!port->host_connected)
+ ret |= POLLHUP;
+
+ return ret;
+}
+
+static int virtconsole_release(struct inode *inode, struct file *filp)
+{
+ struct virtio_console_port *port;
+ struct virtio_console_control cpkt;
+
+ port = filp->private_data;
+
+ /* Notify host of port being closed */
+ cpkt.event = VIRTIO_CONSOLE_PORT_OPEN;
+ cpkt.value = 0;
+ send_buf(filp->private_data, (char *)&cpkt, sizeof(cpkt),
+ VIRTIO_CONSOLE_ID_CONTROL, false);
+
+ return 0;
+}
+
+static int virtconsole_open(struct inode *inode, struct file *filp)
+{
+ struct cdev *cdev = inode->i_cdev;
+ struct virtio_console_port *port;
+ struct virtio_console_control cpkt;
+
+ port = container_of(cdev, struct virtio_console_port, cdev);
+ filp->private_data = port;
+
+ /*
+ * Don't allow opening of console port devices -- that's done
+ * via /dev/hvc
+ */
+ if (port->hvc)
+ return -ENXIO;
+
+ /* Notify host of port being opened */
+ cpkt.event = VIRTIO_CONSOLE_PORT_OPEN;
+ cpkt.value = 1;
+ send_buf(filp->private_data, (char *)&cpkt, sizeof(cpkt),
+ VIRTIO_CONSOLE_ID_CONTROL, false);
+
+ return 0;
+}
+
+/*
+ * The file operations that we support: programs in the guest can open
+ * a console device, read from it, write to it, poll for data and
+ * close it. The devices are at /dev/vconNN
+ */
+static const struct file_operations virtconsole_fops = {
+ .owner = THIS_MODULE,
+ .open = virtconsole_open,
+ .read = virtconsole_read,
+ .write = virtconsole_write,
+ .poll = virtconsole_poll,
+ .release = virtconsole_release,
+};
+
+/*D:310
+ * The put_chars() callback is pretty straightforward.
+ *
+ * We turn the characters into a scatter-gather list, add it to the output
+ * queue and then kick the Host.
+ *
+ * If the data to be output spans more than a page, it's split into
+ * page-sized buffers and then individual buffers are pushed to the Host.
+ */
+static int put_chars(u32 vtermno, const char *buf, int count)
+{
+ struct virtio_console_port *port;
+
+ port = get_port_from_vtermno(vtermno);
+ if (!port)
+ return 0;
+
+ return send_buf(port, buf, count, 0, false);
+}
+
/*D:350
* get_chars() is the callback from the hvc_console infrastructure when
* an interrupt is received.
@@ -206,13 +514,19 @@ static ssize_t fill_readbuf(char *out_buf, size_t
out_count)
*/
static int get_chars(u32 vtermno, char *buf, int count)
{
+ struct virtio_console_port *port;
+
/* If we don't have an input queue yet, we can't get input. */
BUG_ON(!virtconsole.in_vq);
- if (list_empty(&virtconsole.readbuf_head))
+ port = get_port_from_vtermno(vtermno);
+ if (!port)
return 0;
- return fill_readbuf(buf, count);
+ if (list_empty(&port->readbuf_head))
+ return 0;
+
+ return fill_readbuf(port, buf, count, false);
}
/*:*/
@@ -220,29 +534,36 @@ static int get_chars(u32 vtermno, char *buf, int count)
* virtio console configuration. This supports:
* - console resize
*/
-static void virtcons_apply_config(struct virtio_device *dev)
+static void virtcons_apply_config(struct virtio_console_port *port)
{
+ struct virtio_device *vdev;
struct winsize ws;
- if (virtio_has_feature(dev, VIRTIO_CONSOLE_F_SIZE)) {
- dev->config->get(dev,
- offsetof(struct virtio_console_config, cols),
- &ws.ws_col, sizeof(u16));
- dev->config->get(dev,
- offsetof(struct virtio_console_config, rows),
- &ws.ws_row, sizeof(u16));
- hvc_resize(virtconsole.hvc, ws);
+ vdev = port->vcon->vdev;
+ if (virtio_has_feature(port->vcon->vdev, VIRTIO_CONSOLE_F_SIZE)) {
+ vdev->config->get(vdev,
+ offsetof(struct virtio_console_config, cols),
+ &ws.ws_col, sizeof(u16));
+ vdev->config->get(vdev,
+ offsetof(struct virtio_console_config, rows),
+ &ws.ws_row, sizeof(u16));
+ hvc_resize(port->hvc, ws);
}
}
/*
- * we support only one console, the hvc struct is a global var
* We set the configuration at this point, since we now have a tty
*/
static int notifier_add_vio(struct hvc_struct *hp, int data)
{
+ struct virtio_console_port *port;
+
+ port = get_port_from_hvc(hp);
+ if (!port)
+ return -EINVAL;
+
hp->irq_requested = 1;
- virtcons_apply_config(virtconsole.vdev);
+ virtcons_apply_config(port);
return 0;
}
@@ -276,6 +597,91 @@ int __init virtio_cons_early_init(int (*put_chars)(u32,
const char *, int))
return hvc_instantiate(0, 0, &virtio_cons);
}
+int init_port_console(struct virtio_console_port *port)
+{
+ int ret = 0;
+
+ /*
+ * The Host's telling us this port is a console port. Hook it
+ * up with an hvc console.
+ *
+ * To set up and manage our virtual console, we call
+ * hvc_alloc().
+ *
+ * The first argument of hvc_alloc() is the virtual console
+ * number. The second argument is the parameter for the
+ * notification mechanism (like irq number). We currently
+ * leave this as zero, virtqueues have implicit notifications.
+ *
+ * The third argument is a "struct hv_ops" containing the
+ * put_chars() get_chars(), notifier_add() and notifier_del()
+ * pointers. The final argument is the output buffer size: we
+ * can do any size, so we put PAGE_SIZE here.
+ */
+ port->hvc = hvc_alloc(port->vcon->hvc_vtermno, 0, &virtio_cons,
+ PAGE_SIZE);
+ if (IS_ERR(port->hvc)) {
+ ret = PTR_ERR(port->hvc);
+ pr_err("%s: Could not alloc hvc for virtio console port, ret =
%d\n",
+ __func__, ret);
+ port->hvc = NULL;
+ } else {
+ port->vtermno = port->vcon->hvc_vtermno++;
+ }
+ return ret;
+}
+
+/* Any private messages that the Host and Guest want to share */
+static void handle_control_message(struct virtio_console_port *port,
+ struct virtio_console_port_buffer *buf)
+{
+ struct virtio_console_control *cpkt;
+ size_t name_size;
+
+ cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
+
+ switch (cpkt->event) {
+ case VIRTIO_CONSOLE_PORT_OPEN:
+ port->host_connected = cpkt->value;
+ break;
+ case VIRTIO_CONSOLE_PORT_NAME:
+ /*
+ * Skip the size of the header and the cpkt to get the size
+ * of the name that was sent
+ */
+ name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
+
+ port->name = kmalloc(name_size, GFP_KERNEL);
+ if (!port->name) {
+ pr_err("%s: not enough space to store port name\n",
+ __func__);
+ break;
+ }
+ strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
+ name_size - 1);
+ port->name[name_size - 1] = 0;
+ break;
+ case VIRTIO_CONSOLE_CONSOLE_PORT:
+ if (!cpkt->value)
+ break;
+ if (is_console_port(port))
+ break;
+
+ init_port_console(port);
+ /*
+ * Could remove the port here in case init fails - but
+ * have to notify the host first
+ */
+ break;
+ case VIRTIO_CONSOLE_RESIZE:
+ if (!is_console_port(port))
+ break;
+ port->hvc->irq_requested = 1;
+ virtcons_apply_config(port);
+ break;
+ }
+}
+
static struct virtio_console_port_buffer *get_buf(size_t buf_size)
{
struct virtio_console_port_buffer *buf;
@@ -343,30 +749,76 @@ static void alloc_write_bufs(struct virtio_console_struct
*vcon)
}
}
+/*
+ * The workhandler for any buffers that appear on our input queue.
+ * Pick the buffer; if it's some internal control communication meant
+ * for the us, just process it. Otherwise queue it up for the read()
+ * or get_chars() routines to pick the data up later.
+ */
static void virtio_console_rx_work_handler(struct work_struct *work)
{
struct virtio_console_struct *vcon;
+ struct virtio_console_port *port;
struct virtio_console_port_buffer *buf;
+ struct virtio_console_header header;
struct virtqueue *vq;
- unsigned int tmplen;
+ unsigned int tmplen, header_len;
vcon = container_of(work, struct virtio_console_struct, rx_work);
+ header_len = use_multiport(vcon) ? sizeof(header) : 0;
+ port = NULL;
vq = vcon->in_vq;
while ((buf = vq->vq_ops->get_buf(vq, &tmplen))) {
/* The buffer is no longer unused */
list_del(&buf->list);
+ if (use_multiport(vcon)) {
+ memcpy(&header, buf->buf, header_len);
+ port = get_port_from_id(header.id);
+ } else {
+ port = get_port_from_id(0);
+ }
+ if (!port) {
+ /* No valid header at start of buffer. Drop it. */
+ pr_debug("%s: invalid index in buffer, %c %d\n",
+ __func__, buf->buf[0], buf->buf[0]);
+ /*
+ * OPT: This buffer can be added to the unused
+ * list to avoid free / alloc
+ */
+ kfree(buf->buf);
+ kfree(buf);
+ break;
+ }
buf->len = tmplen;
- buf->offset = 0;
+ buf->offset = header_len;
+ if (use_multiport(vcon) && is_control(header.flags)) {
+ handle_control_message(port, buf);
+ /*
+ * OPT: This buffer can be added to the unused
+ * list to avoid free/alloc
+ */
+ kfree(buf->buf);
+ kfree(buf);
+ } else {
+ /*
+ * We might have missed a connection
+ * notification, e.g. before the queues were
+ * initialised.
+ */
+ port->host_connected = true;
+
+ spin_lock(&port->readbuf_list_lock);
+ list_add_tail(&buf->list, &port->readbuf_head);
+ spin_unlock(&port->readbuf_list_lock);
+ }
+ wake_up_interruptible(&port->waitqueue);
- spin_lock(&virtconsole.readbuf_list_lock);
- list_add_tail(&buf->list, &virtconsole.readbuf_head);
- spin_unlock(&virtconsole.readbuf_list_lock);
+ if (is_console_port(port) && !list_empty(&port->readbuf_head))
+ if (hvc_poll(port->hvc))
+ hvc_kick();
}
- if (hvc_poll(virtconsole.hvc))
- hvc_kick();
-
/* Allocate buffers for all the ones that got used up */
fill_receive_queue(&virtconsole);
}
@@ -417,23 +869,95 @@ static void tx_intr(struct virtqueue *vq)
static void config_intr(struct virtio_device *vdev)
{
- /* Handle console size changes */
- virtcons_apply_config(vdev);
+ /*
+ * We'll use this way of resizing only for legacy support. For
+ * newer userspace (VIRTIO_CONSOLE_F_MULTPORT+), use control
+ * messages to indicate console size changes so that it can be
+ * done per-port
+ */
+ virtcons_apply_config(get_port_from_id(0));
+}
+
+static int virtconsole_add_port(u32 port_nr)
+{
+ struct virtio_console_port *port;
+ struct virtio_console_control cpkt;
+ dev_t devt;
+ int ret;
+
+ port = kzalloc(sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ port->vcon = &virtconsole;
+ port->id = port_nr;
+
+ cdev_init(&port->cdev, &virtconsole_fops);
+
+ ret = alloc_chrdev_region(&devt, 0, 1, "virtio-console");
+ if (ret < 0) {
+ pr_err("%s: error allocing chrdev region, ret = %d\n",
+ __func__, ret);
+ goto free_port;
+ }
+ ret = cdev_add(&port->cdev, devt, 1);
+ if (ret < 0) {
+ pr_err("%s: error adding cdev, ret = %d\n", __func__, ret);
+ goto free_chrdev;
+ }
+ port->dev = device_create(port->vcon->class, NULL, devt, NULL,
+ "vcon%u", port_nr);
+ if (IS_ERR(port->dev)) {
+ ret = PTR_ERR(port->dev);
+ pr_err("%s: error creating device, ret = %d\n", __func__, ret);
+ goto free_cdev;
+ }
+ /*
+ * If we're not using multiport support, this has to be a console port
+ */
+ if (!use_multiport(&virtconsole)) {
+ ret = init_port_console(port);
+ if (ret)
+ goto free_cdev;
+ }
+
+ spin_lock_init(&port->readbuf_list_lock);
+ INIT_LIST_HEAD(&port->readbuf_head);
+ init_waitqueue_head(&port->waitqueue);
+
+ list_add_tail(&port->list, &port->vcon->port_head);
+
+ /* Ask for the port's name from Host. */
+ cpkt.event = VIRTIO_CONSOLE_PORT_NAME;
+ send_buf(port, (char *)&cpkt, sizeof(cpkt),
+ VIRTIO_CONSOLE_ID_CONTROL, false);
+
+ return 0;
+free_cdev:
+ cdev_del(&port->cdev);
+free_chrdev:
+ unregister_chrdev_region(devt, 1);
+free_port:
+ kfree(port);
+ return ret;
}
-/*D:370 Once we're further in boot, we get probed like any other virtio device.
+/*D:370
+ * Once we're further in boot, we get probed like any other virtio device.
* At this stage we set up the output virtqueue.
*
- * To set up and manage our virtual console, we call hvc_alloc(). Since we
- * never remove the console device we never need this pointer again.
- *
- * Finally we put our input buffer in the input queue, ready to receive. */
+ * If the host also supports multiple console ports, we check the
+ * config space to see how many ports the host has spawned. We
+ * initialize each port found.
+ */
static int __devinit virtcons_probe(struct virtio_device *vdev)
{
vq_callback_t *callbacks[] = { rx_intr, tx_intr };
const char *names[] = { "input", "output" };
struct virtqueue *vqs[2];
+ u32 i;
int err;
+ bool multiport;
if (virtconsole.vdev) {
pr_err("Multiple virtio-console devices not supported yet\n");
@@ -441,6 +965,17 @@ static int __devinit virtcons_probe(struct virtio_device
*vdev)
}
virtconsole.vdev = vdev;
+ multiport = false;
+ if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
+ multiport = true;
+ vdev->features[0] |= 1 << VIRTIO_CONSOLE_F_MULTIPORT;
+ vdev->config->finalize_features(vdev);
+
+ vdev->config->get(vdev, offsetof(struct virtio_console_config,
+ nr_ports),
+ &virtconsole.config.nr_ports,
+ sizeof(virtconsole.config.nr_ports));
+ }
/* Find the queues. */
/* FIXME: This is why we want to wean off hvc: we do nothing
* when input comes in. */
@@ -459,10 +994,9 @@ static int __devinit virtcons_probe(struct virtio_device
*vdev)
*/
virtio_cons.put_chars = put_chars;
- spin_lock_init(&virtconsole.readbuf_list_lock);
spin_lock_init(&virtconsole.write_list_lock);
- INIT_LIST_HEAD(&virtconsole.readbuf_head);
+ INIT_LIST_HEAD(&virtconsole.port_head);
INIT_LIST_HEAD(&virtconsole.unused_read_head);
INIT_LIST_HEAD(&virtconsole.unused_write_head);
@@ -472,25 +1006,13 @@ static int __devinit virtcons_probe(struct virtio_device
*vdev)
fill_receive_queue(&virtconsole);
alloc_write_bufs(&virtconsole);
- /* The first argument of hvc_alloc() is the virtual console number, so
- * we use zero. The second argument is the parameter for the
- * notification mechanism (like irq number). We currently leave this
- * as zero, virtqueues have implicit notifications.
- *
- * The third argument is a "struct hv_ops" containing the put_chars()
- * get_chars(), notifier_add() and notifier_del() pointers.
- * The final argument is the output buffer size: we can do any size,
- * so we put PAGE_SIZE here. */
- virtconsole.hvc = hvc_alloc(0, 0, &virtio_cons, PAGE_SIZE);
- if (IS_ERR(virtconsole.hvc)) {
- err = PTR_ERR(virtconsole.hvc);
- goto free_vqs;
- }
+ virtconsole_add_port(0);
+ if (multiport)
+ for (i = 1; i < virtconsole.config.nr_ports; i++)
+ virtconsole_add_port(i);
return 0;
-free_vqs:
- vdev->config->del_vqs(vdev);
fail:
return err;
}
@@ -502,6 +1024,7 @@ static struct virtio_device_id id_table[] = {
static unsigned int features[] = {
VIRTIO_CONSOLE_F_SIZE,
+ VIRTIO_CONSOLE_F_MULTIPORT,
};
static struct virtio_driver virtio_console = {
@@ -516,7 +1039,20 @@ static struct virtio_driver virtio_console = {
static int __init init(void)
{
- return register_virtio_driver(&virtio_console);
+ int ret;
+
+ virtconsole.class = class_create(THIS_MODULE, "virtio-console");
+ if (IS_ERR(virtconsole.class)) {
+ pr_err("Error creating virtio-console class\n");
+ ret = PTR_ERR(virtconsole.class);
+ return ret;
+ }
+ ret = register_virtio_driver(&virtio_console);
+ if (ret) {
+ class_destroy(virtconsole.class);
+ return ret;
+ }
+ return 0;
}
module_init(init);
diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h
index fe88517..b93dba4 100644
--- a/include/linux/virtio_console.h
+++ b/include/linux/virtio_console.h
@@ -3,19 +3,59 @@
#include <linux/types.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
-/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
- * anyone can use the definitions to implement compatible drivers/servers. */
+/*
+ * This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
+ * anyone can use the definitions to implement compatible drivers/servers.
+ *
+ * Copyright (C) Red Hat, Inc., 2009
+ */
/* Feature bits */
#define VIRTIO_CONSOLE_F_SIZE 0 /* Does host provide console size? */
+#define VIRTIO_CONSOLE_F_MULTIPORT 1 /* Does host provide multiple ports? */
struct virtio_console_config {
/* colums of the screens */
__u16 cols;
/* rows of the screens */
__u16 rows;
+ /* number of ports added so far */
+ __u32 nr_ports;
} __attribute__((packed));
+/*
+ * A message that's passed between the Host and the Guest for a
+ * particular port.
+ */
+struct virtio_console_control {
+ __u16 event;
+ __u16 value;
+};
+
+/* Some events for control messages */
+#define VIRTIO_CONSOLE_PORT_OPEN 0
+#define VIRTIO_CONSOLE_PORT_NAME 1
+#define VIRTIO_CONSOLE_CONSOLE_PORT 2
+#define VIRTIO_CONSOLE_RESIZE 3
+
+/*
+ * This struct is put in each buffer that gets passed to userspace and
+ * vice-versa
+ */
+struct virtio_console_header {
+ /* Port number */
+ u32 id;
+ /* Some message between host and guest */
+ u32 flags;
+ /*
+ * Complete size of the write request - only sent with the
+ * first buffer for each write request
+ */
+ u32 size;
+} __attribute__((packed));
+
+/* Messages between host and guest ('flags' field in the header above) */
+#define VIRTIO_CONSOLE_ID_CONTROL (1 << 0)
#ifdef __KERNEL__
int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int));
--
1.6.2.5
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