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-rw-r--r--drivers/char/virtio_console.c2297
1 files changed, 2297 insertions, 0 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
new file mode 100644
index 000000000..9fa3c76a2
--- /dev/null
+++ b/drivers/char/virtio_console.c
@@ -0,0 +1,2297 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2006, 2007, 2009 Rusty Russell, IBM Corporation
+ * Copyright (C) 2009, 2010, 2011 Red Hat, Inc.
+ * Copyright (C) 2009, 2010, 2011 Amit Shah <amit.shah@redhat.com>
+ */
+#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/splice.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/virtio.h>
+#include <linux/virtio_console.h>
+#include <linux/wait.h>
+#include <linux/workqueue.h>
+#include <linux/module.h>
+#include <linux/dma-mapping.h>
+#include "../tty/hvc/hvc_console.h"
+
+#define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
+#define VIRTCONS_MAX_PORTS 0x8000
+
+/*
+ * This is a global struct for storing common data for all the devices
+ * this driver handles.
+ *
+ * Mainly, it has a linked list for all the consoles in one place so
+ * that callbacks from hvc for get_chars(), put_chars() work properly
+ * across multiple devices and multiple ports per device.
+ */
+struct ports_driver_data {
+ /* Used for registering chardevs */
+ struct class *class;
+
+ /* Used for exporting per-port information to debugfs */
+ struct dentry *debugfs_dir;
+
+ /* List of all the devices we're handling */
+ struct list_head portdevs;
+
+ /*
+ * This is used to keep track of the number of hvc consoles
+ * spawned by this driver. This number is given as the 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 next_vtermno;
+
+ /* All the console devices handled by this driver */
+ struct list_head consoles;
+};
+static struct ports_driver_data pdrvdata = { .next_vtermno = 1};
+
+static DEFINE_SPINLOCK(pdrvdata_lock);
+static DECLARE_COMPLETION(early_console_added);
+
+/* This struct holds information that's relevant only for console ports */
+struct console {
+ /* We'll place all consoles in a list in the pdrvdata struct */
+ struct list_head list;
+
+ /* The hvc device associated with this console port */
+ struct hvc_struct *hvc;
+
+ /* The size of the console */
+ struct winsize ws;
+
+ /*
+ * This number identifies the number that we used to register
+ * with hvc in hvc_instantiate() and hvc_alloc(); this is the
+ * number passed on by the hvc callbacks to us to
+ * differentiate between the other console ports handled by
+ * this driver
+ */
+ u32 vtermno;
+};
+
+struct port_buffer {
+ char *buf;
+
+ /* size of the buffer in *buf above */
+ size_t size;
+
+ /* used length of the buffer */
+ size_t len;
+ /* offset in the buf from which to consume data */
+ size_t offset;
+
+ /* DMA address of buffer */
+ dma_addr_t dma;
+
+ /* Device we got DMA memory from */
+ struct device *dev;
+
+ /* List of pending dma buffers to free */
+ struct list_head list;
+
+ /* If sgpages == 0 then buf is used */
+ unsigned int sgpages;
+
+ /* sg is used if spages > 0. sg must be the last in is struct */
+ struct scatterlist sg[];
+};
+
+/*
+ * This is a per-device struct that stores data common to all the
+ * ports for that device (vdev->priv).
+ */
+struct ports_device {
+ /* Next portdev in the list, head is in the pdrvdata struct */
+ struct list_head list;
+
+ /*
+ * Workqueue handlers where we process deferred work after
+ * notification
+ */
+ struct work_struct control_work;
+ struct work_struct config_work;
+
+ struct list_head ports;
+
+ /* To protect the list of ports */
+ spinlock_t ports_lock;
+
+ /* To protect the vq operations for the control channel */
+ spinlock_t c_ivq_lock;
+ spinlock_t c_ovq_lock;
+
+ /* max. number of ports this device can hold */
+ u32 max_nr_ports;
+
+ /* The virtio device we're associated with */
+ struct virtio_device *vdev;
+
+ /*
+ * A couple of virtqueues for the control channel: one for
+ * guest->host transfers, one for host->guest transfers
+ */
+ struct virtqueue *c_ivq, *c_ovq;
+
+ /*
+ * A control packet buffer for guest->host requests, protected
+ * by c_ovq_lock.
+ */
+ struct virtio_console_control cpkt;
+
+ /* Array of per-port IO virtqueues */
+ struct virtqueue **in_vqs, **out_vqs;
+
+ /* Major number for this device. Ports will be created as minors. */
+ 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 */
+ struct list_head list;
+
+ /* Pointer to the parent virtio_console device */
+ struct ports_device *portdev;
+
+ /* The current buffer from which data has to be fed to readers */
+ struct port_buffer *inbuf;
+
+ /*
+ * To protect the operations on the in_vq associated with this
+ * port. Has to be a spinlock because it can be called from
+ * interrupt context (get_char()).
+ */
+ spinlock_t inbuf_lock;
+
+ /* Protect the operations on the out_vq. */
+ spinlock_t outvq_lock;
+
+ /* 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;
+
+ /*
+ * 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
+ */
+ struct console cons;
+
+ /* Each port associates with a separate char device */
+ struct cdev *cdev;
+ struct device *dev;
+
+ /* Reference-counting to handle port hot-unplugs and file operations */
+ struct kref kref;
+
+ /* A waitqueue for poll() or blocking read operations */
+ wait_queue_head_t waitqueue;
+
+ /* The 'name' of the port that we expose via sysfs properties */
+ char *name;
+
+ /* We can notify apps of host connect / disconnect events via SIGIO */
+ struct fasync_struct *async_queue;
+
+ /* The 'id' to identify the port with the Host */
+ u32 id;
+
+ bool outvq_full;
+
+ /* Is the host device open */
+ bool host_connected;
+
+ /* We should allow only one process to open a port */
+ bool guest_connected;
+};
+
+/* This is the very early arch-specified put chars function. */
+static int (*early_put_chars)(u32, const char *, int);
+
+static struct port *find_port_by_vtermno(u32 vtermno)
+{
+ struct port *port;
+ struct console *cons;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pdrvdata_lock, flags);
+ list_for_each_entry(cons, &pdrvdata.consoles, list) {
+ if (cons->vtermno == vtermno) {
+ port = container_of(cons, struct port, cons);
+ goto out;
+ }
+ }
+ port = NULL;
+out:
+ spin_unlock_irqrestore(&pdrvdata_lock, flags);
+ return port;
+}
+
+static struct port *find_port_by_devt_in_portdev(struct ports_device *portdev,
+ dev_t dev)
+{
+ struct port *port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&portdev->ports_lock, flags);
+ list_for_each_entry(port, &portdev->ports, list) {
+ if (port->cdev->dev == dev) {
+ kref_get(&port->kref);
+ goto out;
+ }
+ }
+ port = NULL;
+out:
+ spin_unlock_irqrestore(&portdev->ports_lock, flags);
+
+ return port;
+}
+
+static struct port *find_port_by_devt(dev_t dev)
+{
+ struct ports_device *portdev;
+ struct port *port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pdrvdata_lock, flags);
+ list_for_each_entry(portdev, &pdrvdata.portdevs, list) {
+ port = find_port_by_devt_in_portdev(portdev, dev);
+ if (port)
+ goto out;
+ }
+ port = NULL;
+out:
+ spin_unlock_irqrestore(&pdrvdata_lock, flags);
+ return port;
+}
+
+static struct port *find_port_by_id(struct ports_device *portdev, u32 id)
+{
+ struct port *port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&portdev->ports_lock, flags);
+ list_for_each_entry(port, &portdev->ports, list)
+ if (port->id == id)
+ goto out;
+ port = NULL;
+out:
+ spin_unlock_irqrestore(&portdev->ports_lock, flags);
+
+ return port;
+}
+
+static struct port *find_port_by_vq(struct ports_device *portdev,
+ struct virtqueue *vq)
+{
+ struct port *port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&portdev->ports_lock, flags);
+ list_for_each_entry(port, &portdev->ports, list)
+ if (port->in_vq == vq || port->out_vq == vq)
+ goto out;
+ port = NULL;
+out:
+ spin_unlock_irqrestore(&portdev->ports_lock, flags);
+ return port;
+}
+
+static bool is_console_port(struct port *port)
+{
+ if (port->cons.hvc)
+ return true;
+ return false;
+}
+
+static bool is_rproc_serial(const struct virtio_device *vdev)
+{
+ return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
+}
+
+static inline bool use_multiport(struct ports_device *portdev)
+{
+ /*
+ * This condition can be true when put_chars is called from
+ * early_init
+ */
+ if (!portdev->vdev)
+ return false;
+ return __virtio_test_bit(portdev->vdev, VIRTIO_CONSOLE_F_MULTIPORT);
+}
+
+static DEFINE_SPINLOCK(dma_bufs_lock);
+static LIST_HEAD(pending_free_dma_bufs);
+
+static void free_buf(struct port_buffer *buf, bool can_sleep)
+{
+ unsigned int i;
+
+ for (i = 0; i < buf->sgpages; i++) {
+ struct page *page = sg_page(&buf->sg[i]);
+ if (!page)
+ break;
+ put_page(page);
+ }
+
+ if (!buf->dev) {
+ kfree(buf->buf);
+ } else if (is_rproc_enabled) {
+ unsigned long flags;
+
+ /* dma_free_coherent requires interrupts to be enabled. */
+ if (!can_sleep) {
+ /* queue up dma-buffers to be freed later */
+ spin_lock_irqsave(&dma_bufs_lock, flags);
+ list_add_tail(&buf->list, &pending_free_dma_bufs);
+ spin_unlock_irqrestore(&dma_bufs_lock, flags);
+ return;
+ }
+ dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
+
+ /* Release device refcnt and allow it to be freed */
+ put_device(buf->dev);
+ }
+
+ kfree(buf);
+}
+
+static void reclaim_dma_bufs(void)
+{
+ unsigned long flags;
+ struct port_buffer *buf, *tmp;
+ LIST_HEAD(tmp_list);
+
+ if (list_empty(&pending_free_dma_bufs))
+ return;
+
+ /* Create a copy of the pending_free_dma_bufs while holding the lock */
+ spin_lock_irqsave(&dma_bufs_lock, flags);
+ list_cut_position(&tmp_list, &pending_free_dma_bufs,
+ pending_free_dma_bufs.prev);
+ spin_unlock_irqrestore(&dma_bufs_lock, flags);
+
+ /* Release the dma buffers, without irqs enabled */
+ list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
+ list_del(&buf->list);
+ free_buf(buf, true);
+ }
+}
+
+static struct port_buffer *alloc_buf(struct virtio_device *vdev, size_t buf_size,
+ int pages)
+{
+ struct port_buffer *buf;
+
+ reclaim_dma_bufs();
+
+ /*
+ * Allocate buffer and the sg list. The sg list array is allocated
+ * directly after the port_buffer struct.
+ */
+ buf = kmalloc(struct_size(buf, sg, pages), GFP_KERNEL);
+ if (!buf)
+ goto fail;
+
+ buf->sgpages = pages;
+ if (pages > 0) {
+ buf->dev = NULL;
+ buf->buf = NULL;
+ return buf;
+ }
+
+ if (is_rproc_serial(vdev)) {
+ /*
+ * Allocate DMA memory from ancestor. When a virtio
+ * device is created by remoteproc, the DMA memory is
+ * associated with the parent device:
+ * virtioY => remoteprocX#vdevYbuffer.
+ */
+ buf->dev = vdev->dev.parent;
+ if (!buf->dev)
+ goto free_buf;
+
+ /* Increase device refcnt to avoid freeing it */
+ get_device(buf->dev);
+ buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
+ GFP_KERNEL);
+ } else {
+ buf->dev = NULL;
+ buf->buf = kmalloc(buf_size, GFP_KERNEL);
+ }
+
+ if (!buf->buf)
+ goto free_buf;
+ buf->len = 0;
+ buf->offset = 0;
+ buf->size = buf_size;
+ return buf;
+
+free_buf:
+ kfree(buf);
+fail:
+ return NULL;
+}
+
+/* Callers should take appropriate locks */
+static struct port_buffer *get_inbuf(struct port *port)
+{
+ struct port_buffer *buf;
+ unsigned int len;
+
+ if (port->inbuf)
+ return port->inbuf;
+
+ buf = virtqueue_get_buf(port->in_vq, &len);
+ if (buf) {
+ buf->len = min_t(size_t, len, buf->size);
+ buf->offset = 0;
+ port->stats.bytes_received += len;
+ }
+ return buf;
+}
+
+/*
+ * Create a scatter-gather list representing our input buffer and put
+ * it in the queue.
+ *
+ * Callers should take appropriate locks.
+ */
+static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
+{
+ struct scatterlist sg[1];
+ int ret;
+
+ sg_init_one(sg, buf->buf, buf->size);
+
+ ret = virtqueue_add_inbuf(vq, sg, 1, buf, GFP_ATOMIC);
+ virtqueue_kick(vq);
+ if (!ret)
+ ret = vq->num_free;
+ return ret;
+}
+
+/* Discard any unread data this port has. Callers lockers. */
+static void discard_port_data(struct port *port)
+{
+ struct port_buffer *buf;
+ unsigned int err;
+
+ if (!port->portdev) {
+ /* Device has been unplugged. vqs are already gone. */
+ return;
+ }
+ buf = get_inbuf(port);
+
+ err = 0;
+ while (buf) {
+ port->stats.bytes_discarded += buf->len - buf->offset;
+ if (add_inbuf(port->in_vq, buf) < 0) {
+ err++;
+ free_buf(buf, false);
+ }
+ port->inbuf = NULL;
+ buf = get_inbuf(port);
+ }
+ if (err)
+ dev_warn(port->dev, "Errors adding %d buffers back to vq\n",
+ err);
+}
+
+static bool port_has_data(struct port *port)
+{
+ unsigned long flags;
+ bool ret;
+
+ ret = false;
+ spin_lock_irqsave(&port->inbuf_lock, flags);
+ port->inbuf = get_inbuf(port);
+ if (port->inbuf)
+ ret = true;
+
+ spin_unlock_irqrestore(&port->inbuf_lock, flags);
+ return ret;
+}
+
+static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
+ unsigned int event, unsigned int value)
+{
+ struct scatterlist sg[1];
+ struct virtqueue *vq;
+ unsigned int len;
+
+ if (!use_multiport(portdev))
+ return 0;
+
+ vq = portdev->c_ovq;
+
+ spin_lock(&portdev->c_ovq_lock);
+
+ portdev->cpkt.id = cpu_to_virtio32(portdev->vdev, port_id);
+ portdev->cpkt.event = cpu_to_virtio16(portdev->vdev, event);
+ portdev->cpkt.value = cpu_to_virtio16(portdev->vdev, value);
+
+ sg_init_one(sg, &portdev->cpkt, sizeof(struct virtio_console_control));
+
+ if (virtqueue_add_outbuf(vq, sg, 1, &portdev->cpkt, GFP_ATOMIC) == 0) {
+ virtqueue_kick(vq);
+ while (!virtqueue_get_buf(vq, &len)
+ && !virtqueue_is_broken(vq))
+ cpu_relax();
+ }
+
+ spin_unlock(&portdev->c_ovq_lock);
+ return 0;
+}
+
+static ssize_t send_control_msg(struct port *port, unsigned int event,
+ unsigned int value)
+{
+ /* Did the port get unplugged before userspace closed it? */
+ if (port->portdev)
+ return __send_control_msg(port->portdev, port->id, event, value);
+ return 0;
+}
+
+
+/* Callers must take the port->outvq_lock */
+static void reclaim_consumed_buffers(struct port *port)
+{
+ struct port_buffer *buf;
+ unsigned int len;
+
+ if (!port->portdev) {
+ /* Device has been unplugged. vqs are already gone. */
+ return;
+ }
+ while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
+ free_buf(buf, false);
+ port->outvq_full = false;
+ }
+}
+
+static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
+ int nents, size_t in_count,
+ void *data, bool nonblock)
+{
+ struct virtqueue *out_vq;
+ int err;
+ unsigned long flags;
+ unsigned int len;
+
+ out_vq = port->out_vq;
+
+ spin_lock_irqsave(&port->outvq_lock, flags);
+
+ reclaim_consumed_buffers(port);
+
+ err = virtqueue_add_outbuf(out_vq, sg, nents, data, GFP_ATOMIC);
+
+ /* Tell Host to go! */
+ virtqueue_kick(out_vq);
+
+ if (err) {
+ in_count = 0;
+ goto done;
+ }
+
+ if (out_vq->num_free == 0)
+ port->outvq_full = true;
+
+ if (nonblock)
+ goto done;
+
+ /*
+ * Wait till the host acknowledges it pushed out the data we
+ * sent. This is done for data from the hvc_console; the tty
+ * operations are performed with spinlocks held so we can't
+ * sleep here. An alternative would be to copy the data to a
+ * buffer and relax the spinning requirement. The downside is
+ * we need to kmalloc a GFP_ATOMIC buffer each time the
+ * console driver writes something out.
+ */
+ while (!virtqueue_get_buf(out_vq, &len)
+ && !virtqueue_is_broken(out_vq))
+ 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
+ */
+ return in_count;
+}
+
+/*
+ * Give out the data that's requested from the buffer that we have
+ * queued up.
+ */
+static ssize_t fill_readbuf(struct port *port, char __user *out_buf,
+ size_t out_count, bool to_user)
+{
+ struct port_buffer *buf;
+ unsigned long flags;
+
+ if (!out_count || !port_has_data(port))
+ return 0;
+
+ buf = port->inbuf;
+ out_count = min(out_count, buf->len - buf->offset);
+
+ if (to_user) {
+ ssize_t ret;
+
+ ret = copy_to_user(out_buf, buf->buf + buf->offset, out_count);
+ if (ret)
+ return -EFAULT;
+ } else {
+ memcpy((__force char *)out_buf, buf->buf + buf->offset,
+ out_count);
+ }
+
+ buf->offset += out_count;
+
+ if (buf->offset == buf->len) {
+ /*
+ * We're done using all the data in this buffer.
+ * Re-queue so that the Host can send us more data.
+ */
+ spin_lock_irqsave(&port->inbuf_lock, flags);
+ port->inbuf = NULL;
+
+ if (add_inbuf(port->in_vq, buf) < 0)
+ dev_warn(port->dev, "failed add_buf\n");
+
+ spin_unlock_irqrestore(&port->inbuf_lock, flags);
+ }
+ /* Return the number of bytes actually copied */
+ return out_count;
+}
+
+/* The condition that must be true for polling to end */
+static bool will_read_block(struct port *port)
+{
+ if (!port->guest_connected) {
+ /* Port got hot-unplugged. Let's exit. */
+ return false;
+ }
+ return !port_has_data(port) && port->host_connected;
+}
+
+static bool will_write_block(struct port *port)
+{
+ bool ret;
+
+ if (!port->guest_connected) {
+ /* Port got hot-unplugged. Let's exit. */
+ return false;
+ }
+ if (!port->host_connected)
+ return true;
+
+ spin_lock_irq(&port->outvq_lock);
+ /*
+ * Check if the Host has consumed any buffers since we last
+ * sent data (this is only applicable for nonblocking ports).
+ */
+ reclaim_consumed_buffers(port);
+ ret = port->outvq_full;
+ spin_unlock_irq(&port->outvq_lock);
+
+ return ret;
+}
+
+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;
+
+ /* Port is hot-unplugged. */
+ if (!port->guest_connected)
+ return -ENODEV;
+
+ 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_freezable(port->waitqueue,
+ !will_read_block(port));
+ if (ret < 0)
+ return ret;
+ }
+ /* Port got hot-unplugged while we were waiting above. */
+ if (!port->guest_connected)
+ return -ENODEV;
+ /*
+ * 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 int wait_port_writable(struct port *port, bool nonblock)
+{
+ int ret;
+
+ if (will_write_block(port)) {
+ if (nonblock)
+ return -EAGAIN;
+
+ ret = wait_event_freezable(port->waitqueue,
+ !will_write_block(port));
+ if (ret < 0)
+ return ret;
+ }
+ /* Port got hot-unplugged. */
+ if (!port->guest_connected)
+ return -ENODEV;
+
+ return 0;
+}
+
+static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
+ size_t count, loff_t *offp)
+{
+ struct port *port;
+ struct port_buffer *buf;
+ ssize_t ret;
+ bool nonblock;
+ struct scatterlist sg[1];
+
+ /* Userspace could be out to fool us */
+ if (!count)
+ return 0;
+
+ port = filp->private_data;
+
+ nonblock = filp->f_flags & O_NONBLOCK;
+
+ ret = wait_port_writable(port, nonblock);
+ if (ret < 0)
+ return ret;
+
+ count = min((size_t)(32 * 1024), count);
+
+ buf = alloc_buf(port->portdev->vdev, count, 0);
+ if (!buf)
+ return -ENOMEM;
+
+ ret = copy_from_user(buf->buf, ubuf, count);
+ if (ret) {
+ ret = -EFAULT;
+ goto free_buf;
+ }
+
+ /*
+ * We now ask send_buf() to not spin for generic ports -- we
+ * can re-use the same code path that non-blocking file
+ * descriptors take for blocking file descriptors since the
+ * wait is already done and we're certain the write will go
+ * through to the host.
+ */
+ nonblock = true;
+ sg_init_one(sg, buf->buf, count);
+ ret = __send_to_port(port, sg, 1, count, buf, nonblock);
+
+ if (nonblock && ret > 0)
+ goto out;
+
+free_buf:
+ free_buf(buf, true);
+out:
+ return ret;
+}
+
+struct sg_list {
+ unsigned int n;
+ unsigned int size;
+ size_t len;
+ struct scatterlist *sg;
+};
+
+static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
+ struct splice_desc *sd)
+{
+ struct sg_list *sgl = sd->u.data;
+ unsigned int offset, len;
+
+ if (sgl->n == sgl->size)
+ return 0;
+
+ /* Try lock this page */
+ if (pipe_buf_try_steal(pipe, buf)) {
+ /* Get reference and unlock page for moving */
+ get_page(buf->page);
+ unlock_page(buf->page);
+
+ len = min(buf->len, sd->len);
+ sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
+ } else {
+ /* Failback to copying a page */
+ struct page *page = alloc_page(GFP_KERNEL);
+ char *src;
+
+ if (!page)
+ return -ENOMEM;
+
+ offset = sd->pos & ~PAGE_MASK;
+
+ len = sd->len;
+ if (len + offset > PAGE_SIZE)
+ len = PAGE_SIZE - offset;
+
+ src = kmap_atomic(buf->page);
+ memcpy(page_address(page) + offset, src + buf->offset, len);
+ kunmap_atomic(src);
+
+ sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
+ }
+ sgl->n++;
+ sgl->len += len;
+
+ return len;
+}
+
+/* Faster zero-copy write by splicing */
+static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
+ struct file *filp, loff_t *ppos,
+ size_t len, unsigned int flags)
+{
+ struct port *port = filp->private_data;
+ struct sg_list sgl;
+ ssize_t ret;
+ struct port_buffer *buf;
+ struct splice_desc sd = {
+ .total_len = len,
+ .flags = flags,
+ .pos = *ppos,
+ .u.data = &sgl,
+ };
+ unsigned int occupancy;
+
+ /*
+ * Rproc_serial does not yet support splice. To support splice
+ * pipe_to_sg() must allocate dma-buffers and copy content from
+ * regular pages to dma pages. And alloc_buf and free_buf must
+ * support allocating and freeing such a list of dma-buffers.
+ */
+ if (is_rproc_serial(port->out_vq->vdev))
+ return -EINVAL;
+
+ pipe_lock(pipe);
+ ret = 0;
+ if (pipe_empty(pipe->head, pipe->tail))
+ goto error_out;
+
+ ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
+ if (ret < 0)
+ goto error_out;
+
+ occupancy = pipe_occupancy(pipe->head, pipe->tail);
+ buf = alloc_buf(port->portdev->vdev, 0, occupancy);
+
+ if (!buf) {
+ ret = -ENOMEM;
+ goto error_out;
+ }
+
+ sgl.n = 0;
+ sgl.len = 0;
+ sgl.size = occupancy;
+ sgl.sg = buf->sg;
+ sg_init_table(sgl.sg, sgl.size);
+ ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
+ pipe_unlock(pipe);
+ if (likely(ret > 0))
+ ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
+
+ if (unlikely(ret <= 0))
+ free_buf(buf, true);
+ return ret;
+
+error_out:
+ pipe_unlock(pipe);
+ return ret;
+}
+
+static __poll_t port_fops_poll(struct file *filp, poll_table *wait)
+{
+ struct port *port;
+ __poll_t ret;
+
+ port = filp->private_data;
+ poll_wait(filp, &port->waitqueue, wait);
+
+ if (!port->guest_connected) {
+ /* Port got unplugged */
+ return EPOLLHUP;
+ }
+ ret = 0;
+ if (!will_read_block(port))
+ ret |= EPOLLIN | EPOLLRDNORM;
+ if (!will_write_block(port))
+ ret |= EPOLLOUT;
+ if (!port->host_connected)
+ ret |= EPOLLHUP;
+
+ return ret;
+}
+
+static void remove_port(struct kref *kref);
+
+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);
+
+ spin_lock_irq(&port->inbuf_lock);
+ port->guest_connected = false;
+
+ discard_port_data(port);
+
+ spin_unlock_irq(&port->inbuf_lock);
+
+ spin_lock_irq(&port->outvq_lock);
+ reclaim_consumed_buffers(port);
+ spin_unlock_irq(&port->outvq_lock);
+
+ reclaim_dma_bufs();
+ /*
+ * Locks aren't necessary here as a port can't be opened after
+ * unplug, and if a port isn't unplugged, a kref would already
+ * exist for the port. Plus, taking ports_lock here would
+ * create a dependency on other locks taken by functions
+ * inside remove_port if we're the last holder of the port,
+ * creating many problems.
+ */
+ kref_put(&port->kref, remove_port);
+
+ return 0;
+}
+
+static int port_fops_open(struct inode *inode, struct file *filp)
+{
+ struct cdev *cdev = inode->i_cdev;
+ struct port *port;
+ int ret;
+
+ /* We get the port with a kref here */
+ port = find_port_by_devt(cdev->dev);
+ if (!port) {
+ /* Port was unplugged before we could proceed */
+ return -ENXIO;
+ }
+ filp->private_data = port;
+
+ /*
+ * Don't allow opening of console port devices -- that's done
+ * via /dev/hvc
+ */
+ if (is_console_port(port)) {
+ ret = -ENXIO;
+ goto out;
+ }
+
+ /* Allow only one process to open a particular port at a time */
+ spin_lock_irq(&port->inbuf_lock);
+ if (port->guest_connected) {
+ spin_unlock_irq(&port->inbuf_lock);
+ ret = -EBUSY;
+ goto out;
+ }
+
+ port->guest_connected = true;
+ spin_unlock_irq(&port->inbuf_lock);
+
+ spin_lock_irq(&port->outvq_lock);
+ /*
+ * There might be a chance that we missed reclaiming a few
+ * buffers in the window of the port getting previously closed
+ * and opening now.
+ */
+ reclaim_consumed_buffers(port);
+ spin_unlock_irq(&port->outvq_lock);
+
+ nonseekable_open(inode, filp);
+
+ /* Notify host of port being opened */
+ send_control_msg(filp->private_data, VIRTIO_CONSOLE_PORT_OPEN, 1);
+
+ return 0;
+out:
+ kref_put(&port->kref, remove_port);
+ return ret;
+}
+
+static int port_fops_fasync(int fd, struct file *filp, int mode)
+{
+ struct port *port;
+
+ port = filp->private_data;
+ return fasync_helper(fd, filp, mode, &port->async_queue);
+}
+
+/*
+ * 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,
+ .splice_write = port_fops_splice_write,
+ .poll = port_fops_poll,
+ .release = port_fops_release,
+ .fasync = port_fops_fasync,
+ .llseek = no_llseek,
+};
+
+/*
+ * 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. Then we sit here waiting for
+ * it to finish: inefficient in theory, but in practice
+ * implementations will do it immediately.
+ */
+static int put_chars(u32 vtermno, const char *buf, int count)
+{
+ struct port *port;
+ struct scatterlist sg[1];
+ void *data;
+ int ret;
+
+ if (unlikely(early_put_chars))
+ return early_put_chars(vtermno, buf, count);
+
+ port = find_port_by_vtermno(vtermno);
+ if (!port)
+ return -EPIPE;
+
+ data = kmemdup(buf, count, GFP_ATOMIC);
+ if (!data)
+ return -ENOMEM;
+
+ sg_init_one(sg, data, count);
+ ret = __send_to_port(port, sg, 1, count, data, false);
+ kfree(data);
+ return ret;
+}
+
+/*
+ * get_chars() is the callback from the hvc_console infrastructure
+ * when an interrupt is received.
+ *
+ * We call out to fill_readbuf that gets us the required data from the
+ * buffers that are queued up.
+ */
+static int get_chars(u32 vtermno, char *buf, int count)
+{
+ struct port *port;
+
+ /* If we've not set up the port yet, we have no input to give. */
+ if (unlikely(early_put_chars))
+ return 0;
+
+ port = find_port_by_vtermno(vtermno);
+ if (!port)
+ return -EPIPE;
+
+ /* If we don't have an input queue yet, we can't get input. */
+ BUG_ON(!port->in_vq);
+
+ return fill_readbuf(port, (__force char __user *)buf, count, false);
+}
+
+static void resize_console(struct port *port)
+{
+ struct virtio_device *vdev;
+
+ /* The port could have been hot-unplugged */
+ if (!port || !is_console_port(port))
+ return;
+
+ vdev = port->portdev->vdev;
+
+ /* Don't test F_SIZE at all if we're rproc: not a valid feature! */
+ if (!is_rproc_serial(vdev) &&
+ virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
+ hvc_resize(port->cons.hvc, port->cons.ws);
+}
+
+/* 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 port *port;
+
+ port = find_port_by_vtermno(hp->vtermno);
+ if (!port)
+ return -EINVAL;
+
+ hp->irq_requested = 1;
+ resize_console(port);
+
+ return 0;
+}
+
+static void notifier_del_vio(struct hvc_struct *hp, int data)
+{
+ hp->irq_requested = 0;
+}
+
+/* The operations for console ports. */
+static const struct hv_ops hv_ops = {
+ .get_chars = get_chars,
+ .put_chars = put_chars,
+ .notifier_add = notifier_add_vio,
+ .notifier_del = notifier_del_vio,
+ .notifier_hangup = notifier_del_vio,
+};
+
+/*
+ * Console drivers are initialized very early so boot messages can go
+ * out, so we do things slightly differently from the generic virtio
+ * initialization of the net and block drivers.
+ *
+ * At this stage, the console is output-only. It's too early to set
+ * up a virtqueue, so we let the drivers do some boutique early-output
+ * thing.
+ */
+int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
+{
+ early_put_chars = put_chars;
+ return hvc_instantiate(0, 0, &hv_ops);
+}
+
+static int init_port_console(struct port *port)
+{
+ int ret;
+
+ /*
+ * 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->cons.vtermno = pdrvdata.next_vtermno;
+
+ port->cons.hvc = hvc_alloc(port->cons.vtermno, 0, &hv_ops, PAGE_SIZE);
+ if (IS_ERR(port->cons.hvc)) {
+ ret = PTR_ERR(port->cons.hvc);
+ dev_err(port->dev,
+ "error %d allocating hvc for port\n", ret);
+ port->cons.hvc = NULL;
+ return ret;
+ }
+ spin_lock_irq(&pdrvdata_lock);
+ pdrvdata.next_vtermno++;
+ list_add_tail(&port->cons.list, &pdrvdata.consoles);
+ spin_unlock_irq(&pdrvdata_lock);
+ port->guest_connected = true;
+
+ /*
+ * Start using the new console output if this is the first
+ * console to come up.
+ */
+ if (early_put_chars)
+ early_put_chars = NULL;
+
+ /* Notify host of port being opened */
+ send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
+
+ return 0;
+}
+
+static ssize_t show_port_name(struct device *dev,
+ struct device_attribute *attr, char *buffer)
+{
+ struct port *port;
+
+ port = dev_get_drvdata(dev);
+
+ return sprintf(buffer, "%s\n", port->name);
+}
+
+static DEVICE_ATTR(name, S_IRUGO, show_port_name, NULL);
+
+static struct attribute *port_sysfs_entries[] = {
+ &dev_attr_name.attr,
+ NULL
+};
+
+static const struct attribute_group port_attribute_group = {
+ .name = NULL, /* put in device directory */
+ .attrs = port_sysfs_entries,
+};
+
+static int port_debugfs_show(struct seq_file *s, void *data)
+{
+ struct port *port = s->private;
+
+ seq_printf(s, "name: %s\n", port->name ? port->name : "");
+ seq_printf(s, "guest_connected: %d\n", port->guest_connected);
+ seq_printf(s, "host_connected: %d\n", port->host_connected);
+ seq_printf(s, "outvq_full: %d\n", port->outvq_full);
+ seq_printf(s, "bytes_sent: %lu\n", port->stats.bytes_sent);
+ seq_printf(s, "bytes_received: %lu\n", port->stats.bytes_received);
+ seq_printf(s, "bytes_discarded: %lu\n", port->stats.bytes_discarded);
+ seq_printf(s, "is_console: %s\n",
+ is_console_port(port) ? "yes" : "no");
+ seq_printf(s, "console_vtermno: %u\n", port->cons.vtermno);
+
+ return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(port_debugfs);
+
+static void set_console_size(struct port *port, u16 rows, u16 cols)
+{
+ if (!port || !is_console_port(port))
+ return;
+
+ port->cons.ws.ws_row = rows;
+ port->cons.ws.ws_col = cols;
+}
+
+static int fill_queue(struct virtqueue *vq, spinlock_t *lock)
+{
+ struct port_buffer *buf;
+ int nr_added_bufs;
+ int ret;
+
+ nr_added_bufs = 0;
+ do {
+ buf = alloc_buf(vq->vdev, PAGE_SIZE, 0);
+ if (!buf)
+ return -ENOMEM;
+
+ spin_lock_irq(lock);
+ ret = add_inbuf(vq, buf);
+ if (ret < 0) {
+ spin_unlock_irq(lock);
+ free_buf(buf, true);
+ return ret;
+ }
+ nr_added_bufs++;
+ spin_unlock_irq(lock);
+ } while (ret > 0);
+
+ return nr_added_bufs;
+}
+
+static void send_sigio_to_port(struct port *port)
+{
+ if (port->async_queue && port->guest_connected)
+ kill_fasync(&port->async_queue, SIGIO, POLL_OUT);
+}
+
+static int add_port(struct ports_device *portdev, u32 id)
+{
+ char debugfs_name[16];
+ struct port *port;
+ dev_t devt;
+ int err;
+
+ port = kmalloc(sizeof(*port), GFP_KERNEL);
+ if (!port) {
+ err = -ENOMEM;
+ goto fail;
+ }
+ kref_init(&port->kref);
+
+ port->portdev = portdev;
+ port->id = id;
+
+ port->name = NULL;
+ port->inbuf = NULL;
+ port->cons.hvc = NULL;
+ port->async_queue = NULL;
+
+ port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
+ port->cons.vtermno = 0;
+
+ port->host_connected = port->guest_connected = false;
+ port->stats = (struct port_stats) { 0 };
+
+ port->outvq_full = false;
+
+ port->in_vq = portdev->in_vqs[port->id];
+ port->out_vq = portdev->out_vqs[port->id];
+
+ port->cdev = cdev_alloc();
+ if (!port->cdev) {
+ dev_err(&port->portdev->vdev->dev, "Error allocating cdev\n");
+ err = -ENOMEM;
+ goto free_port;
+ }
+ port->cdev->ops = &port_fops;
+
+ devt = MKDEV(portdev->chr_major, id);
+ err = cdev_add(port->cdev, devt, 1);
+ if (err < 0) {
+ dev_err(&port->portdev->vdev->dev,
+ "Error %d adding cdev for port %u\n", err, id);
+ goto free_cdev;
+ }
+ port->dev = device_create(pdrvdata.class, &port->portdev->vdev->dev,
+ devt, port, "vport%up%u",
+ port->portdev->vdev->index, id);
+ if (IS_ERR(port->dev)) {
+ err = PTR_ERR(port->dev);
+ dev_err(&port->portdev->vdev->dev,
+ "Error %d creating device for port %u\n",
+ err, id);
+ goto free_cdev;
+ }
+
+ spin_lock_init(&port->inbuf_lock);
+ spin_lock_init(&port->outvq_lock);
+ init_waitqueue_head(&port->waitqueue);
+
+ /* We can safely ignore ENOSPC because it means
+ * the queue already has buffers. Buffers are removed
+ * only by virtcons_remove(), not by unplug_port()
+ */
+ err = fill_queue(port->in_vq, &port->inbuf_lock);
+ if (err < 0 && err != -ENOSPC) {
+ dev_err(port->dev, "Error allocating inbufs\n");
+ goto free_device;
+ }
+
+ if (is_rproc_serial(port->portdev->vdev))
+ /*
+ * For rproc_serial assume remote processor is connected.
+ * rproc_serial does not want the console port, only
+ * the generic port implementation.
+ */
+ port->host_connected = true;
+ else if (!use_multiport(port->portdev)) {
+ /*
+ * If we're not using multiport support,
+ * this has to be a console port.
+ */
+ err = init_port_console(port);
+ if (err)
+ goto free_inbufs;
+ }
+
+ spin_lock_irq(&portdev->ports_lock);
+ list_add_tail(&port->list, &port->portdev->ports);
+ spin_unlock_irq(&portdev->ports_lock);
+
+ /*
+ * Tell the Host we're set so that it can send us various
+ * configuration parameters for this port (eg, port name,
+ * caching, whether this is a console port, etc.)
+ */
+ send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
+
+ /*
+ * Finally, create the debugfs file that we can use to
+ * inspect a port's state at any time
+ */
+ snprintf(debugfs_name, sizeof(debugfs_name), "vport%up%u",
+ port->portdev->vdev->index, id);
+ port->debugfs_file = debugfs_create_file(debugfs_name, 0444,
+ pdrvdata.debugfs_dir,
+ port, &port_debugfs_fops);
+ return 0;
+
+free_inbufs:
+free_device:
+ device_destroy(pdrvdata.class, port->dev->devt);
+free_cdev:
+ cdev_del(port->cdev);
+free_port:
+ kfree(port);
+fail:
+ /* The host might want to notify management sw about port add failure */
+ __send_control_msg(portdev, id, VIRTIO_CONSOLE_PORT_READY, 0);
+ return err;
+}
+
+/* No users remain, remove all port-specific data. */
+static void remove_port(struct kref *kref)
+{
+ struct port *port;
+
+ port = container_of(kref, struct port, kref);
+
+ kfree(port);
+}
+
+static void remove_port_data(struct port *port)
+{
+ spin_lock_irq(&port->inbuf_lock);
+ /* Remove unused data this port might have received. */
+ discard_port_data(port);
+ spin_unlock_irq(&port->inbuf_lock);
+
+ spin_lock_irq(&port->outvq_lock);
+ reclaim_consumed_buffers(port);
+ spin_unlock_irq(&port->outvq_lock);
+}
+
+/*
+ * Port got unplugged. Remove port from portdev's list and drop the
+ * kref reference. If no userspace has this port opened, it will
+ * result in immediate removal the port.
+ */
+static void unplug_port(struct port *port)
+{
+ spin_lock_irq(&port->portdev->ports_lock);
+ list_del(&port->list);
+ spin_unlock_irq(&port->portdev->ports_lock);
+
+ spin_lock_irq(&port->inbuf_lock);
+ if (port->guest_connected) {
+ /* Let the app know the port is going down. */
+ send_sigio_to_port(port);
+
+ /* Do this after sigio is actually sent */
+ port->guest_connected = false;
+ port->host_connected = false;
+
+ wake_up_interruptible(&port->waitqueue);
+ }
+ spin_unlock_irq(&port->inbuf_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);
+ }
+
+ remove_port_data(port);
+
+ /*
+ * We should just assume the device itself has gone off --
+ * else a close on an open port later will try to send out a
+ * control message.
+ */
+ port->portdev = NULL;
+
+ sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
+ device_destroy(pdrvdata.class, port->dev->devt);
+ cdev_del(port->cdev);
+
+ debugfs_remove(port->debugfs_file);
+ kfree(port->name);
+
+ /*
+ * Locks around here are not necessary - a port can't be
+ * opened after we removed the port struct from ports_list
+ * above.
+ */
+ kref_put(&port->kref, remove_port);
+}
+
+/* Any private messages that the Host and Guest want to share */
+static void handle_control_message(struct virtio_device *vdev,
+ struct ports_device *portdev,
+ struct port_buffer *buf)
+{
+ struct virtio_console_control *cpkt;
+ struct port *port;
+ size_t name_size;
+ int err;
+
+ cpkt = (struct virtio_console_control *)(buf->buf + buf->offset);
+
+ port = find_port_by_id(portdev, virtio32_to_cpu(vdev, cpkt->id));
+ if (!port &&
+ cpkt->event != cpu_to_virtio16(vdev, VIRTIO_CONSOLE_PORT_ADD)) {
+ /* No valid header at start of buffer. Drop it. */
+ dev_dbg(&portdev->vdev->dev,
+ "Invalid index %u in control packet\n", cpkt->id);
+ return;
+ }
+
+ switch (virtio16_to_cpu(vdev, cpkt->event)) {
+ case VIRTIO_CONSOLE_PORT_ADD:
+ if (port) {
+ dev_dbg(&portdev->vdev->dev,
+ "Port %u already added\n", port->id);
+ send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
+ break;
+ }
+ if (virtio32_to_cpu(vdev, cpkt->id) >=
+ portdev->max_nr_ports) {
+ dev_warn(&portdev->vdev->dev,
+ "Request for adding port with "
+ "out-of-bound id %u, max. supported id: %u\n",
+ cpkt->id, portdev->max_nr_ports - 1);
+ break;
+ }
+ add_port(portdev, virtio32_to_cpu(vdev, cpkt->id));
+ break;
+ case VIRTIO_CONSOLE_PORT_REMOVE:
+ unplug_port(port);
+ break;
+ case VIRTIO_CONSOLE_CONSOLE_PORT:
+ if (!cpkt->value)
+ break;
+ if (is_console_port(port))
+ 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.
+ */
+ break;
+ case VIRTIO_CONSOLE_RESIZE: {
+ struct {
+ __u16 rows;
+ __u16 cols;
+ } size;
+
+ if (!is_console_port(port))
+ break;
+
+ memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt),
+ sizeof(size));
+ set_console_size(port, size.rows, size.cols);
+
+ port->cons.hvc->irq_requested = 1;
+ resize_console(port);
+ break;
+ }
+ case VIRTIO_CONSOLE_PORT_OPEN:
+ port->host_connected = virtio16_to_cpu(vdev, cpkt->value);
+ wake_up_interruptible(&port->waitqueue);
+ /*
+ * If the host port got closed and the host had any
+ * unconsumed buffers, we'll be able to reclaim them
+ * now.
+ */
+ spin_lock_irq(&port->outvq_lock);
+ reclaim_consumed_buffers(port);
+ spin_unlock_irq(&port->outvq_lock);
+
+ /*
+ * If the guest is connected, it'll be interested in
+ * knowing the host connection state changed.
+ */
+ spin_lock_irq(&port->inbuf_lock);
+ send_sigio_to_port(port);
+ spin_unlock_irq(&port->inbuf_lock);
+ 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
+ */
+ name_size = buf->len - buf->offset - sizeof(*cpkt) + 1;
+
+ port->name = kmalloc(name_size, GFP_KERNEL);
+ if (!port->name) {
+ dev_err(port->dev,
+ "Not enough space to store port name\n");
+ break;
+ }
+ strncpy(port->name, buf->buf + buf->offset + sizeof(*cpkt),
+ name_size - 1);
+ port->name[name_size - 1] = 0;
+
+ /*
+ * Since we only have one sysfs attribute, 'name',
+ * create it only if we have a name for the port.
+ */
+ err = sysfs_create_group(&port->dev->kobj,
+ &port_attribute_group);
+ if (err) {
+ dev_err(port->dev,
+ "Error %d creating sysfs device attributes\n",
+ err);
+ } else {
+ /*
+ * Generate a udev event so that appropriate
+ * symlinks can be created based on udev
+ * rules.
+ */
+ kobject_uevent(&port->dev->kobj, KOBJ_CHANGE);
+ }
+ break;
+ }
+}
+
+static void control_work_handler(struct work_struct *work)
+{
+ struct ports_device *portdev;
+ struct virtqueue *vq;
+ struct port_buffer *buf;
+ unsigned int len;
+
+ portdev = container_of(work, struct ports_device, control_work);
+ vq = portdev->c_ivq;
+
+ spin_lock(&portdev->c_ivq_lock);
+ while ((buf = virtqueue_get_buf(vq, &len))) {
+ spin_unlock(&portdev->c_ivq_lock);
+
+ buf->len = min_t(size_t, len, buf->size);
+ buf->offset = 0;
+
+ handle_control_message(vq->vdev, portdev, buf);
+
+ spin_lock(&portdev->c_ivq_lock);
+ if (add_inbuf(portdev->c_ivq, buf) < 0) {
+ dev_warn(&portdev->vdev->dev,
+ "Error adding buffer to queue\n");
+ free_buf(buf, false);
+ }
+ }
+ spin_unlock(&portdev->c_ivq_lock);
+}
+
+static void flush_bufs(struct virtqueue *vq, bool can_sleep)
+{
+ struct port_buffer *buf;
+ unsigned int len;
+
+ while ((buf = virtqueue_get_buf(vq, &len)))
+ free_buf(buf, can_sleep);
+}
+
+static void out_intr(struct virtqueue *vq)
+{
+ struct port *port;
+
+ port = find_port_by_vq(vq->vdev->priv, vq);
+ if (!port) {
+ flush_bufs(vq, false);
+ return;
+ }
+
+ wake_up_interruptible(&port->waitqueue);
+}
+
+static void in_intr(struct virtqueue *vq)
+{
+ struct port *port;
+ unsigned long flags;
+
+ port = find_port_by_vq(vq->vdev->priv, vq);
+ if (!port) {
+ flush_bufs(vq, false);
+ return;
+ }
+
+ spin_lock_irqsave(&port->inbuf_lock, flags);
+ port->inbuf = get_inbuf(port);
+
+ /*
+ * Normally the port should not accept data when the port is
+ * closed. For generic serial ports, the host won't (shouldn't)
+ * send data till the guest is connected. But this condition
+ * can be reached when a console port is not yet connected (no
+ * tty is spawned) and the other side sends out data over the
+ * vring, or when a remote devices start sending data before
+ * the ports are opened.
+ *
+ * A generic serial port will discard data if not connected,
+ * while console ports and rproc-serial ports accepts data at
+ * any time. rproc-serial is initiated with guest_connected to
+ * false because port_fops_open expects this. Console ports are
+ * hooked up with an HVC console and is initialized with
+ * guest_connected to true.
+ */
+
+ if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
+ discard_port_data(port);
+
+ /* Send a SIGIO indicating new data in case the process asked for it */
+ send_sigio_to_port(port);
+
+ spin_unlock_irqrestore(&port->inbuf_lock, flags);
+
+ wake_up_interruptible(&port->waitqueue);
+
+ if (is_console_port(port) && hvc_poll(port->cons.hvc))
+ hvc_kick();
+}
+
+static void control_intr(struct virtqueue *vq)
+{
+ struct ports_device *portdev;
+
+ portdev = vq->vdev->priv;
+ schedule_work(&portdev->control_work);
+}
+
+static void config_intr(struct virtio_device *vdev)
+{
+ struct ports_device *portdev;
+
+ portdev = vdev->priv;
+
+ if (!use_multiport(portdev))
+ schedule_work(&portdev->config_work);
+}
+
+static void config_work_handler(struct work_struct *work)
+{
+ struct ports_device *portdev;
+
+ portdev = container_of(work, struct ports_device, config_work);
+ if (!use_multiport(portdev)) {
+ struct virtio_device *vdev;
+ struct port *port;
+ u16 rows, cols;
+
+ vdev = portdev->vdev;
+ virtio_cread(vdev, struct virtio_console_config, cols, &cols);
+ virtio_cread(vdev, struct virtio_console_config, rows, &rows);
+
+ port = find_port_by_id(portdev, 0);
+ set_console_size(port, rows, cols);
+
+ /*
+ * 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.
+ */
+ resize_console(port);
+ }
+}
+
+static int init_vqs(struct ports_device *portdev)
+{
+ vq_callback_t **io_callbacks;
+ char **io_names;
+ struct virtqueue **vqs;
+ u32 i, j, nr_ports, nr_queues;
+ int err;
+
+ nr_ports = portdev->max_nr_ports;
+ nr_queues = use_multiport(portdev) ? (nr_ports + 1) * 2 : 2;
+
+ vqs = kmalloc_array(nr_queues, sizeof(struct virtqueue *), GFP_KERNEL);
+ io_callbacks = kmalloc_array(nr_queues, sizeof(vq_callback_t *),
+ GFP_KERNEL);
+ io_names = kmalloc_array(nr_queues, sizeof(char *), GFP_KERNEL);
+ portdev->in_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
+ GFP_KERNEL);
+ portdev->out_vqs = kmalloc_array(nr_ports, sizeof(struct virtqueue *),
+ GFP_KERNEL);
+ if (!vqs || !io_callbacks || !io_names || !portdev->in_vqs ||
+ !portdev->out_vqs) {
+ err = -ENOMEM;
+ goto free;
+ }
+
+ /*
+ * For backward compat (newer host but older guest), the host
+ * spawns a console port first and also inits the vqs for port
+ * 0 before others.
+ */
+ j = 0;
+ io_callbacks[j] = in_intr;
+ io_callbacks[j + 1] = out_intr;
+ io_names[j] = "input";
+ io_names[j + 1] = "output";
+ j += 2;
+
+ if (use_multiport(portdev)) {
+ io_callbacks[j] = control_intr;
+ io_callbacks[j + 1] = NULL;
+ io_names[j] = "control-i";
+ io_names[j + 1] = "control-o";
+
+ for (i = 1; i < nr_ports; i++) {
+ j += 2;
+ io_callbacks[j] = in_intr;
+ io_callbacks[j + 1] = out_intr;
+ io_names[j] = "input";
+ io_names[j + 1] = "output";
+ }
+ }
+ /* Find the queues. */
+ err = virtio_find_vqs(portdev->vdev, nr_queues, vqs,
+ io_callbacks,
+ (const char **)io_names, NULL);
+ if (err)
+ goto free;
+
+ j = 0;
+ portdev->in_vqs[0] = vqs[0];
+ portdev->out_vqs[0] = vqs[1];
+ j += 2;
+ if (use_multiport(portdev)) {
+ portdev->c_ivq = vqs[j];
+ portdev->c_ovq = vqs[j + 1];
+
+ for (i = 1; i < nr_ports; i++) {
+ j += 2;
+ portdev->in_vqs[i] = vqs[j];
+ portdev->out_vqs[i] = vqs[j + 1];
+ }
+ }
+ kfree(io_names);
+ kfree(io_callbacks);
+ kfree(vqs);
+
+ return 0;
+
+free:
+ kfree(portdev->out_vqs);
+ kfree(portdev->in_vqs);
+ kfree(io_names);
+ kfree(io_callbacks);
+ kfree(vqs);
+
+ return err;
+}
+
+static const struct file_operations portdev_fops = {
+ .owner = THIS_MODULE,
+};
+
+static void remove_vqs(struct ports_device *portdev)
+{
+ struct virtqueue *vq;
+
+ virtio_device_for_each_vq(portdev->vdev, vq) {
+ struct port_buffer *buf;
+
+ flush_bufs(vq, true);
+ while ((buf = virtqueue_detach_unused_buf(vq)))
+ free_buf(buf, true);
+ }
+ portdev->vdev->config->del_vqs(portdev->vdev);
+ kfree(portdev->in_vqs);
+ kfree(portdev->out_vqs);
+}
+
+static void virtcons_remove(struct virtio_device *vdev)
+{
+ struct ports_device *portdev;
+ struct port *port, *port2;
+
+ portdev = vdev->priv;
+
+ spin_lock_irq(&pdrvdata_lock);
+ list_del(&portdev->list);
+ spin_unlock_irq(&pdrvdata_lock);
+
+ /* Device is going away, exit any polling for buffers */
+ virtio_break_device(vdev);
+ if (use_multiport(portdev))
+ flush_work(&portdev->control_work);
+ else
+ flush_work(&portdev->config_work);
+
+ /* Disable interrupts for vqs */
+ virtio_reset_device(vdev);
+ /* Finish up work that's lined up */
+ if (use_multiport(portdev))
+ cancel_work_sync(&portdev->control_work);
+ else
+ cancel_work_sync(&portdev->config_work);
+
+ list_for_each_entry_safe(port, port2, &portdev->ports, list)
+ unplug_port(port);
+
+ unregister_chrdev(portdev->chr_major, "virtio-portsdev");
+
+ /*
+ * When yanking out a device, we immediately lose the
+ * (device-side) queues. So there's no point in keeping the
+ * guest side around till we drop our final reference. This
+ * also means that any ports which are in an open state will
+ * have to just stop using the port, as the vqs are going
+ * away.
+ */
+ remove_vqs(portdev);
+ kfree(portdev);
+}
+
+/*
+ * Once we're further in boot, we get probed like any other virtio
+ * device.
+ *
+ * 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 virtcons_probe(struct virtio_device *vdev)
+{
+ struct ports_device *portdev;
+ int err;
+ bool multiport;
+ bool early = early_put_chars != NULL;
+
+ /* We only need a config space if features are offered */
+ if (!vdev->config->get &&
+ (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)
+ || virtio_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT))) {
+ dev_err(&vdev->dev, "%s failure: config access disabled\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ /* Ensure to read early_put_chars now */
+ barrier();
+
+ portdev = kmalloc(sizeof(*portdev), GFP_KERNEL);
+ if (!portdev) {
+ err = -ENOMEM;
+ goto fail;
+ }
+
+ /* Attach this portdev to this virtio_device, and vice-versa. */
+ portdev->vdev = vdev;
+ vdev->priv = portdev;
+
+ portdev->chr_major = register_chrdev(0, "virtio-portsdev",
+ &portdev_fops);
+ if (portdev->chr_major < 0) {
+ dev_err(&vdev->dev,
+ "Error %d registering chrdev for device %u\n",
+ portdev->chr_major, vdev->index);
+ err = portdev->chr_major;
+ goto free;
+ }
+
+ multiport = false;
+ portdev->max_nr_ports = 1;
+
+ /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
+ if (!is_rproc_serial(vdev) &&
+ virtio_cread_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
+ struct virtio_console_config, max_nr_ports,
+ &portdev->max_nr_ports) == 0) {
+ if (portdev->max_nr_ports == 0 ||
+ portdev->max_nr_ports > VIRTCONS_MAX_PORTS) {
+ dev_err(&vdev->dev,
+ "Invalidate max_nr_ports %d",
+ portdev->max_nr_ports);
+ err = -EINVAL;
+ goto free;
+ }
+ multiport = true;
+ }
+
+ err = init_vqs(portdev);
+ if (err < 0) {
+ dev_err(&vdev->dev, "Error %d initializing vqs\n", err);
+ goto free_chrdev;
+ }
+
+ spin_lock_init(&portdev->ports_lock);
+ INIT_LIST_HEAD(&portdev->ports);
+ INIT_LIST_HEAD(&portdev->list);
+
+ virtio_device_ready(portdev->vdev);
+
+ INIT_WORK(&portdev->config_work, &config_work_handler);
+ INIT_WORK(&portdev->control_work, &control_work_handler);
+
+ if (multiport) {
+ spin_lock_init(&portdev->c_ivq_lock);
+ spin_lock_init(&portdev->c_ovq_lock);
+
+ err = fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
+ if (err < 0) {
+ dev_err(&vdev->dev,
+ "Error allocating buffers for control queue\n");
+ /*
+ * The host might want to notify mgmt sw about device
+ * add failure.
+ */
+ __send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
+ VIRTIO_CONSOLE_DEVICE_READY, 0);
+ /* Device was functional: we need full cleanup. */
+ virtcons_remove(vdev);
+ return err;
+ }
+ } else {
+ /*
+ * For backward compatibility: Create a console port
+ * if we're running on older host.
+ */
+ add_port(portdev, 0);
+ }
+
+ spin_lock_irq(&pdrvdata_lock);
+ list_add_tail(&portdev->list, &pdrvdata.portdevs);
+ spin_unlock_irq(&pdrvdata_lock);
+
+ __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_chrdev:
+ unregister_chrdev(portdev->chr_major, "virtio-portsdev");
+free:
+ kfree(portdev);
+fail:
+ return err;
+}
+
+static const struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
+ { 0 },
+};
+MODULE_DEVICE_TABLE(virtio, id_table);
+
+static const unsigned int features[] = {
+ VIRTIO_CONSOLE_F_SIZE,
+ VIRTIO_CONSOLE_F_MULTIPORT,
+};
+
+static const struct virtio_device_id rproc_serial_id_table[] = {
+#if IS_ENABLED(CONFIG_REMOTEPROC)
+ { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
+#endif
+ { 0 },
+};
+MODULE_DEVICE_TABLE(virtio, rproc_serial_id_table);
+
+static const unsigned int rproc_serial_features[] = {
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int virtcons_freeze(struct virtio_device *vdev)
+{
+ struct ports_device *portdev;
+ struct port *port;
+
+ portdev = vdev->priv;
+
+ virtio_reset_device(vdev);
+
+ if (use_multiport(portdev))
+ virtqueue_disable_cb(portdev->c_ivq);
+ cancel_work_sync(&portdev->control_work);
+ cancel_work_sync(&portdev->config_work);
+ /*
+ * Once more: if control_work_handler() was running, it would
+ * enable the cb as the last step.
+ */
+ if (use_multiport(portdev))
+ virtqueue_disable_cb(portdev->c_ivq);
+
+ list_for_each_entry(port, &portdev->ports, list) {
+ virtqueue_disable_cb(port->in_vq);
+ virtqueue_disable_cb(port->out_vq);
+ /*
+ * We'll ask the host later if the new invocation has
+ * the port opened or closed.
+ */
+ port->host_connected = false;
+ remove_port_data(port);
+ }
+ remove_vqs(portdev);
+
+ return 0;
+}
+
+static int virtcons_restore(struct virtio_device *vdev)
+{
+ struct ports_device *portdev;
+ struct port *port;
+ int ret;
+
+ portdev = vdev->priv;
+
+ ret = init_vqs(portdev);
+ if (ret)
+ return ret;
+
+ virtio_device_ready(portdev->vdev);
+
+ if (use_multiport(portdev))
+ fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
+
+ list_for_each_entry(port, &portdev->ports, list) {
+ port->in_vq = portdev->in_vqs[port->id];
+ port->out_vq = portdev->out_vqs[port->id];
+
+ fill_queue(port->in_vq, &port->inbuf_lock);
+
+ /* Get port open/close status on the host */
+ send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);
+
+ /*
+ * If a port was open at the time of suspending, we
+ * have to let the host know that it's still open.
+ */
+ if (port->guest_connected)
+ send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1);
+ }
+ return 0;
+}
+#endif
+
+static struct virtio_driver virtio_console = {
+ .feature_table = features,
+ .feature_table_size = ARRAY_SIZE(features),
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = virtcons_probe,
+ .remove = virtcons_remove,
+ .config_changed = config_intr,
+#ifdef CONFIG_PM_SLEEP
+ .freeze = virtcons_freeze,
+ .restore = virtcons_restore,
+#endif
+};
+
+static struct virtio_driver virtio_rproc_serial = {
+ .feature_table = rproc_serial_features,
+ .feature_table_size = ARRAY_SIZE(rproc_serial_features),
+ .driver.name = "virtio_rproc_serial",
+ .driver.owner = THIS_MODULE,
+ .id_table = rproc_serial_id_table,
+ .probe = virtcons_probe,
+ .remove = virtcons_remove,
+};
+
+static int __init virtio_console_init(void)
+{
+ int err;
+
+ pdrvdata.class = class_create(THIS_MODULE, "virtio-ports");
+ if (IS_ERR(pdrvdata.class)) {
+ err = PTR_ERR(pdrvdata.class);
+ pr_err("Error %d creating virtio-ports class\n", err);
+ return err;
+ }
+
+ pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);
+ INIT_LIST_HEAD(&pdrvdata.consoles);
+ INIT_LIST_HEAD(&pdrvdata.portdevs);
+
+ err = register_virtio_driver(&virtio_console);
+ if (err < 0) {
+ pr_err("Error %d registering virtio driver\n", err);
+ goto free;
+ }
+ err = register_virtio_driver(&virtio_rproc_serial);
+ if (err < 0) {
+ pr_err("Error %d registering virtio rproc serial driver\n",
+ err);
+ goto unregister;
+ }
+ return 0;
+unregister:
+ unregister_virtio_driver(&virtio_console);
+free:
+ debugfs_remove_recursive(pdrvdata.debugfs_dir);
+ class_destroy(pdrvdata.class);
+ return err;
+}
+
+static void __exit virtio_console_fini(void)
+{
+ reclaim_dma_bufs();
+
+ unregister_virtio_driver(&virtio_console);
+ unregister_virtio_driver(&virtio_rproc_serial);
+
+ class_destroy(pdrvdata.class);
+ debugfs_remove_recursive(pdrvdata.debugfs_dir);
+}
+module_init(virtio_console_init);
+module_exit(virtio_console_fini);
+
+MODULE_DESCRIPTION("Virtio console driver");
+MODULE_LICENSE("GPL");