diff options
| -rw-r--r-- | drivers/char/virtio_console.c | 164 | ||||
| -rw-r--r-- | include/linux/virtio_console.h | 1 |
2 files changed, 164 insertions, 1 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 64ef476d6557..ece1546fbb20 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -19,11 +19,15 @@ #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" @@ -163,8 +167,14 @@ struct port { struct cdev cdev; struct device *dev; + /* A waitqueue for poll() or blocking read operations */ + wait_queue_head_t waitqueue; + /* The 'id' to identify the port with the Host */ u32 id; + + /* Is the host device open */ + bool host_connected; }; /* This is the very early arch-specified put chars function. */ @@ -417,6 +427,146 @@ static ssize_t fill_readbuf(struct port *port, char *out_buf, size_t out_count, return out_count; } +/* The condition that must be true for polling to end */ +static bool wait_is_over(struct port *port) +{ + return port_has_data(port) || !port->host_connected; +} + +static ssize_t port_fops_read(struct file *filp, char __user *ubuf, + size_t count, loff_t *offp) +{ + struct port *port; + ssize_t ret; + + port = filp->private_data; + + if (!port_has_data(port)) { + /* + * 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 (!port_has_data(port) && !port->host_connected) + return 0; + + return fill_readbuf(port, ubuf, count, true); +} + +static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, + size_t count, loff_t *offp) +{ + struct port *port; + char *buf; + ssize_t ret; + + port = filp->private_data; + + count = min((size_t)(32 * 1024), count); + + buf = kmalloc(count, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = copy_from_user(buf, ubuf, count); + if (ret) { + ret = -EFAULT; + goto free_buf; + } + + ret = send_buf(port, buf, count); +free_buf: + kfree(buf); + return ret; +} + +static unsigned int port_fops_poll(struct file *filp, poll_table *wait) +{ + struct port *port; + unsigned int ret; + + port = filp->private_data; + poll_wait(filp, &port->waitqueue, wait); + + ret = 0; + if (port->inbuf) + ret |= POLLIN | POLLRDNORM; + if (port->host_connected) + ret |= POLLOUT; + if (!port->host_connected) + ret |= POLLHUP; + + return ret; +} + +static int port_fops_release(struct inode *inode, struct file *filp) +{ + struct port *port; + + port = filp->private_data; + + /* Notify host of port being closed */ + send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0); + + return 0; +} + +static int port_fops_open(struct inode *inode, struct file *filp) +{ + struct cdev *cdev = inode->i_cdev; + struct port *port; + + port = container_of(cdev, struct port, cdev); + filp->private_data = port; + + /* + * Don't allow opening of console port devices -- that's done + * via /dev/hvc + */ + if (is_console_port(port)) + return -ENXIO; + + /* Notify host of port being opened */ + send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1); + + 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/vport<device number>p<port number> + */ +static const struct file_operations port_fops = { + .owner = THIS_MODULE, + .open = port_fops_open, + .read = port_fops_read, + .write = port_fops_write, + .poll = port_fops_poll, + .release = port_fops_release, +}; + /* * The put_chars() callback is pretty straightforward. * @@ -560,6 +710,9 @@ int init_port_console(struct port *port) list_add_tail(&port->cons.list, &pdrvdata.consoles); spin_unlock_irq(&pdrvdata_lock); + /* Notify host of port being opened */ + send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1); + return 0; } @@ -599,6 +752,10 @@ static void handle_control_message(struct ports_device *portdev, port->cons.hvc->irq_requested = 1; resize_console(port); break; + case VIRTIO_CONSOLE_PORT_OPEN: + port->host_connected = cpkt->value; + wake_up_interruptible(&port->waitqueue); + break; } } @@ -645,6 +802,8 @@ static void in_intr(struct virtqueue *vq) spin_unlock_irqrestore(&port->inbuf_lock, flags); + wake_up_interruptible(&port->waitqueue); + if (is_console_port(port) && hvc_poll(port->cons.hvc)) hvc_kick(); } @@ -697,10 +856,12 @@ static int add_port(struct ports_device *portdev, u32 id) port->inbuf = NULL; port->cons.hvc = NULL; + port->host_connected = false; + port->in_vq = portdev->in_vqs[port->id]; port->out_vq = portdev->out_vqs[port->id]; - cdev_init(&port->cdev, NULL); + cdev_init(&port->cdev, &port_fops); devt = MKDEV(portdev->chr_major, id); err = cdev_add(&port->cdev, devt, 1); @@ -721,6 +882,7 @@ static int add_port(struct ports_device *portdev, u32 id) } spin_lock_init(&port->inbuf_lock); + init_waitqueue_head(&port->waitqueue); inbuf = alloc_buf(PAGE_SIZE); if (!inbuf) { diff --git a/include/linux/virtio_console.h b/include/linux/virtio_console.h index f4d183b5b493..bd0e2a596f93 100644 --- a/include/linux/virtio_console.h +++ b/include/linux/virtio_console.h @@ -39,6 +39,7 @@ struct virtio_console_control { #define VIRTIO_CONSOLE_PORT_READY 0 #define VIRTIO_CONSOLE_CONSOLE_PORT 1 #define VIRTIO_CONSOLE_RESIZE 2 +#define VIRTIO_CONSOLE_PORT_OPEN 3 #ifdef __KERNEL__ int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int)); |