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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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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/idr.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 <linux/string_choices.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 exporting per-port information to debugfs */ struct dentry *debugfs_dir;
/* List of all the devices we're handling */ struct list_head portdevs;
/* All the console devices handled by this driver */ struct list_head consoles;};
static struct ports_driver_data pdrvdata;
static const struct class port_class = { .name = "virtio-ports",};
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;};
static DEFINE_IDA(vtermno_ida);
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[] __counted_by(sgpages);};
/* * 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;
/* * Set to true during PM freeze to block TX paths that may race * with virtqueue teardown (e.g. hvc put_chars with no_console_suspend). */ bool pm_freezing;};
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;};
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;}
/* * Finds a port by the virtqueue and returns a pointer to struct port * with the reference count incremented. * * Callers MUST decrement it when finished. */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) { kref_get(&port->kref); 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, gfp_t gfp){ 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_flex(*buf, sg, pages, gfp); 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); } else { buf->dev = NULL; buf->buf = kmalloc(buf_size, gfp); }
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, struct port_buffer *buf, bool nonblock){ struct virtqueue *out_vq; int err; unsigned long flags; unsigned int len; struct ports_device *portdev;
spin_lock_irqsave(&port->outvq_lock, flags);
portdev = READ_ONCE(port->portdev);
if (!portdev) { in_count = 0; goto free_and_done; }
/* * Check freeze flag under the lock so that the flag check and * virtqueue_add_outbuf() are atomic with respect to * remove_port_data() which also takes outvq_lock. This * guarantees that once remove_port_data() returns, no new * buffers can be added before remove_vqs() tears down the vq. * Pairs with smp_store_release() in virtcons_freeze/restore. */ if (smp_load_acquire(&portdev->pm_freezing)) /* pairs with freeze/restore */ goto free_and_done;
out_vq = port->out_vq;
reclaim_consumed_buffers(port);
err = virtqueue_add_outbuf(out_vq, sg, nents, buf, GFP_ATOMIC);
/* Tell Host to go! */ virtqueue_kick(out_vq);
if (err) { in_count = 0; goto free_and_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. * * Spin until host returns the buffer. * Capture the returned buf so we can free it. * If broken, buf == NULL and buf stays in the vq; * remove_vqs() will call virtqueue_detach_unused_buf() -> free_buf(). */ while (!(buf = virtqueue_get_buf(out_vq, &len)) && !virtqueue_is_broken(out_vq)) cpu_relax();
free_and_done: if (buf) free_buf(buf, false);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, u8 __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 u8 *)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, GFP_KERNEL); if (!buf) return -ENOMEM;
ret = copy_from_user(buf->buf, ubuf, count); if (ret) { free_buf(buf, true); return -EFAULT; }
/* * 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); return __send_to_port(port, sg, 1, count, buf, nonblock);}
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_local_page(buf->page); memcpy(page_address(page) + offset, src + buf->offset, len); kunmap_local(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_is_empty(pipe)) goto error_out;
ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK); if (ret < 0) goto error_out;
occupancy = pipe_buf_usage(pipe); buf = alloc_buf(port->portdev->vdev, 0, occupancy, GFP_KERNEL);
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); else 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,};
/* * 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 ssize_t put_chars(u32 vtermno, const u8 *buf, size_t count){ struct port *port; struct scatterlist sg[1]; struct port_buffer *pbuf; struct ports_device *portdev;
port = find_port_by_vtermno(vtermno); if (!port) return -EPIPE;
/* * Silently drop output in two cases, both by returning count so * that the hvc layer does not spin-retry: * * 1. Device hot-unplug (!portdev): portdev was NULLed by * unplug_port() after hvc_remove() was already called, so * the hvc layer will stop invoking put_chars() very soon. * Returning count avoids a pointless retry loop in the * interim. * * 2. PM freeze (pm_freezing): the hvc console stays active * under no_console_suspend but virtqueues are being torn * down. Drop the output silently so the hvc layer does not * stall suspend. * * This early check avoids a pointless GFP_ATOMIC allocation; * __send_to_port() rechecks under outvq_lock for correctness. * Pairs with smp_store_release() in virtcons_freeze/restore. */ portdev = READ_ONCE(port->portdev); if (!portdev || smp_load_acquire(&portdev->pm_freezing)) /* pairs with freeze/restore */ return count;
pbuf = alloc_buf(portdev->vdev, count, 0, GFP_ATOMIC); if (!pbuf) return -ENOMEM;
memcpy(pbuf->buf, buf, count); pbuf->len = count; sg_init_one(sg, pbuf->buf, count);
/* * Ownership of pbuf is transferred to __send_to_port(). * Do not touch or free pbuf after this call. */ return __send_to_port(port, sg, 1, count, pbuf, false);}
/* * 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 ssize_t get_chars(u32 vtermno, u8 *buf, size_t count){ struct port *port;
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 u8 __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,};
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. */ ret = ida_alloc_min(&vtermno_ida, 1, GFP_KERNEL); if (ret < 0) return ret;
port->cons.vtermno = ret; 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; ida_free(&vtermno_ida, port->cons.vtermno); return ret; } spin_lock_irq(&pdrvdata_lock); list_add_tail(&port->cons.list, &pdrvdata.consoles); spin_unlock_irq(&pdrvdata_lock); port->guest_connected = true;
/* 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", str_yes_no(is_console_port(port))); 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, GFP_KERNEL); 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){ struct port *port; dev_t devt; int err;
port = kmalloc_obj(*port); 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(&port_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 */ port->debugfs_file = debugfs_create_file(dev_name(port->dev), 0444, pdrvdata.debugfs_dir, port, &port_debugfs_fops); return 0;
free_inbufs:free_device: device_destroy(&port_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); ida_free(&vtermno_ida, port->cons.vtermno); }
remove_port_data(port);
/* * Null out portdev under outvq_lock so that __send_to_port() * cannot race: it checks port->portdev inside the same lock * and bails out if NULL, preventing any buffer from being * enqueued to an already torn-down virtqueue. Also prevents * a close on an open port later from sending a stale control * message. */ spin_lock_irq(&port->outvq_lock); port->portdev = NULL; spin_unlock_irq(&port->outvq_lock);
sysfs_remove_group(&port->dev->kobj, &port_attribute_group); device_destroy(&port_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", virtio32_to_cpu(vdev, 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", virtio32_to_cpu(vdev, 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 { __virtio16 cols; __virtio16 rows; } size;
if (!is_console_port(port)) break;
memcpy(&size, buf->buf + buf->offset + sizeof(*cpkt), sizeof(size)); set_console_size(port, virtio16_to_cpu(vdev, size.rows), virtio16_to_cpu(vdev, 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; } strscpy(port->name, buf->buf + buf->offset + sizeof(*cpkt), name_size);
/* * 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); kref_put(&port->kref, remove_port);}
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();
kref_put(&port->kref, remove_port);}
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 update_size_from_config(struct ports_device *portdev){ struct virtio_device *vdev; struct port *port; u16 rows, cols;
vdev = portdev->vdev;
/* * We'll use this way of resizing only for legacy support. * For multiport devices, use control messages to indicate * console size changes so that it can be done per-port. * * Don't test F_SIZE at all if we're rproc: not a valid feature. */ if (is_rproc_serial(vdev) || use_multiport(portdev) || !virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) return;
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); resize_console(port);}
static void config_work_handler(struct work_struct *work){ struct ports_device *portdev;
portdev = container_of(work, struct ports_device, config_work); update_size_from_config(portdev);}
static int init_vqs(struct ports_device *portdev){ struct virtqueue_info *vqs_info; 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_objs(struct virtqueue *, nr_queues); vqs_info = kzalloc_objs(*vqs_info, nr_queues); portdev->in_vqs = kmalloc_objs(struct virtqueue *, nr_ports); portdev->out_vqs = kmalloc_objs(struct virtqueue *, nr_ports); if (!vqs || !vqs_info || !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; vqs_info[j].callback = in_intr; vqs_info[j + 1].callback = out_intr; vqs_info[j].name = "input"; vqs_info[j + 1].name = "output"; j += 2;
if (use_multiport(portdev)) { vqs_info[j].callback = control_intr; vqs_info[j].name = "control-i"; vqs_info[j + 1].name = "control-o";
for (i = 1; i < nr_ports; i++) { j += 2; vqs_info[j].callback = in_intr; vqs_info[j + 1].callback = out_intr; vqs_info[j].name = "input"; vqs_info[j + 1].name = "output"; } } /* Find the queues. */ err = virtio_find_vqs(portdev->vdev, nr_queues, vqs, vqs_info, 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(vqs_info); kfree(vqs);
return 0;
free: kfree(portdev->out_vqs); kfree(portdev->in_vqs); kfree(vqs_info); 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; bool multiport = use_multiport(portdev);
virtio_device_for_each_vq(portdev->vdev, vq) { struct port_buffer *buf; unsigned int len;
/* * c_ovq cookies are &portdev->cpkt, not port_buffer. * Detach them but do not free_buf(). */ if (multiport && vq == portdev->c_ovq) { spin_lock(&portdev->c_ovq_lock); while (virtqueue_get_buf(vq, &len)) ; while (virtqueue_detach_unused_buf(vq)) ; spin_unlock(&portdev->c_ovq_lock); } else { flush_bufs(vq, true); while ((buf = virtqueue_detach_unused_buf(vq))) free_buf(buf, true); } cond_resched(); } 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;
/* 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; }
portdev = kmalloc_obj(*portdev); if (!portdev) { err = -ENOMEM; goto fail; }
/* Attach this portdev to this virtio_device, and vice-versa. */ portdev->vdev = vdev; vdev->priv = portdev; portdev->pm_freezing = false;
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; }
spin_lock_init(&portdev->ports_lock); INIT_LIST_HEAD(&portdev->ports); INIT_LIST_HEAD(&portdev->list);
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 = init_vqs(portdev); if (err < 0) { dev_err(&vdev->dev, "Error %d initializing vqs\n", err); goto free_chrdev; }
virtio_device_ready(portdev->vdev);
if (multiport) { 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);
update_size_from_config(portdev);
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_SLEEPstatic int virtcons_freeze(struct virtio_device *vdev){ struct ports_device *portdev; struct port *port; unsigned long flags;
portdev = vdev->priv;
/* * Block TX paths (put_chars, __send_to_port) before resetting the * device and tearing down virtqueues. This prevents races with * hvc console writes that remain active under no_console_suspend. */ smp_store_release(&portdev->pm_freezing, true);
/* * Synchronize with any concurrent __send_to_port() that may have * passed the pm_freezing check. By acquiring and releasing the * outvq_lock for each port, we ensure all active TX paths have * completed before we reset the device. */ spin_lock_irqsave(&portdev->ports_lock, flags); list_for_each_entry(port, &portdev->ports, list) { spin_lock(&port->outvq_lock); spin_unlock(&port->outvq_lock); } spin_unlock_irqrestore(&portdev->ports_lock, flags);
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);
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); }
/* * Populate the control receive queue only after the list iteration * is complete. If we fill this queue before iterating, the host could * immediately deliver a VIRTIO_CONSOLE_PORT_REMOVE message. * This would trigger the control workqueue, which modifies the * portdev->ports list concurrently with the unprotected loop above, * leading to a Use-After-Free and list corruption. */ if (use_multiport(portdev)) fill_queue(portdev->c_ivq, &portdev->c_ivq_lock);
/* * Allow TX paths only after all port->out_vq pointers have * been reassigned to the newly allocated virtqueues. */ smp_store_release(&portdev->pm_freezing, false);
return 0;}#endif
static struct virtio_driver virtio_console = { .feature_table = features, .feature_table_size = ARRAY_SIZE(features), .driver.name = KBUILD_MODNAME, .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", .id_table = rproc_serial_id_table, .probe = virtcons_probe, .remove = virtcons_remove,};
static int __init virtio_console_init(void){ int err;
err = class_register(&port_class); if (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_unregister(&port_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_unregister(&port_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");