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Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001/* Copyright (C) 2009 Red Hat, Inc.
2 * Copyright (C) 2006 Rusty Russell IBM Corporation
3 *
4 * Author: Michael S. Tsirkin <mst@redhat.com>
5 *
6 * Inspiration, some code, and most witty comments come from
Rob Landley61516582011-05-06 09:27:36 -07007 * Documentation/virtual/lguest/lguest.c, by Rusty Russell
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00008 *
9 * This work is licensed under the terms of the GNU GPL, version 2.
10 *
11 * Generic code for virtio server in host kernel.
12 */
13
14#include <linux/eventfd.h>
15#include <linux/vhost.h>
16#include <linux/virtio_net.h>
17#include <linux/mm.h>
Michael S. Tsirkin64e1c802010-10-06 15:34:45 +020018#include <linux/mmu_context.h>
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000019#include <linux/miscdevice.h>
20#include <linux/mutex.h>
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000021#include <linux/rcupdate.h>
22#include <linux/poll.h>
23#include <linux/file.h>
24#include <linux/highmem.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090025#include <linux/slab.h>
Tejun Heoc23f3442010-06-02 20:40:00 +020026#include <linux/kthread.h>
Michael S. Tsirkin9e3d1952010-07-27 22:56:50 +030027#include <linux/cgroup.h>
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000028
29#include <linux/net.h>
30#include <linux/if_packet.h>
31#include <linux/if_arp.h>
32
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000033#include "vhost.h"
34
35enum {
36 VHOST_MEMORY_MAX_NREGIONS = 64,
37 VHOST_MEMORY_F_LOG = 0x1,
38};
39
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +000040static unsigned vhost_zcopy_mask __read_mostly;
41
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +030042#define vhost_used_event(vq) ((u16 __user *)&vq->avail->ring[vq->num])
43#define vhost_avail_event(vq) ((u16 __user *)&vq->used->ring[vq->num])
44
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000045static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
46 poll_table *pt)
47{
48 struct vhost_poll *poll;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000049
Krishna Kumard47effe2011-03-01 17:06:37 +053050 poll = container_of(pt, struct vhost_poll, table);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000051 poll->wqh = wqh;
52 add_wait_queue(wqh, &poll->wait);
53}
54
55static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,
56 void *key)
57{
Tejun Heoc23f3442010-06-02 20:40:00 +020058 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
59
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000060 if (!((unsigned long)key & poll->mask))
61 return 0;
62
Tejun Heoc23f3442010-06-02 20:40:00 +020063 vhost_poll_queue(poll);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000064 return 0;
65}
66
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +030067static void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000068{
Tejun Heoc23f3442010-06-02 20:40:00 +020069 INIT_LIST_HEAD(&work->node);
70 work->fn = fn;
71 init_waitqueue_head(&work->done);
72 work->flushing = 0;
73 work->queue_seq = work->done_seq = 0;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000074}
75
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +030076/* Init poll structure */
77void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
78 unsigned long mask, struct vhost_dev *dev)
79{
80 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
81 init_poll_funcptr(&poll->table, vhost_poll_func);
82 poll->mask = mask;
83 poll->dev = dev;
84
85 vhost_work_init(&poll->work, fn);
86}
87
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000088/* Start polling a file. We add ourselves to file's wait queue. The caller must
89 * keep a reference to a file until after vhost_poll_stop is called. */
90void vhost_poll_start(struct vhost_poll *poll, struct file *file)
91{
92 unsigned long mask;
Krishna Kumard47effe2011-03-01 17:06:37 +053093
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +000094 mask = file->f_op->poll(file, &poll->table);
95 if (mask)
96 vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
97}
98
99/* Stop polling a file. After this function returns, it becomes safe to drop the
100 * file reference. You must also flush afterwards. */
101void vhost_poll_stop(struct vhost_poll *poll)
102{
103 remove_wait_queue(poll->wqh, &poll->wait);
104}
105
Michael S. Tsirkin0174b0c2011-01-10 10:03:20 +0200106static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work,
107 unsigned seq)
108{
109 int left;
Krishna Kumard47effe2011-03-01 17:06:37 +0530110
Michael S. Tsirkin0174b0c2011-01-10 10:03:20 +0200111 spin_lock_irq(&dev->work_lock);
112 left = seq - work->done_seq;
113 spin_unlock_irq(&dev->work_lock);
114 return left <= 0;
115}
116
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300117static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000118{
Tejun Heoc23f3442010-06-02 20:40:00 +0200119 unsigned seq;
Tejun Heoc23f3442010-06-02 20:40:00 +0200120 int flushing;
121
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300122 spin_lock_irq(&dev->work_lock);
Tejun Heoc23f3442010-06-02 20:40:00 +0200123 seq = work->queue_seq;
124 work->flushing++;
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300125 spin_unlock_irq(&dev->work_lock);
Michael S. Tsirkin0174b0c2011-01-10 10:03:20 +0200126 wait_event(work->done, vhost_work_seq_done(dev, work, seq));
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300127 spin_lock_irq(&dev->work_lock);
Tejun Heoc23f3442010-06-02 20:40:00 +0200128 flushing = --work->flushing;
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300129 spin_unlock_irq(&dev->work_lock);
Tejun Heoc23f3442010-06-02 20:40:00 +0200130 BUG_ON(flushing < 0);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000131}
132
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300133/* Flush any work that has been scheduled. When calling this, don't hold any
134 * locks that are also used by the callback. */
135void vhost_poll_flush(struct vhost_poll *poll)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000136{
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300137 vhost_work_flush(poll->dev, &poll->work);
138}
139
140static inline void vhost_work_queue(struct vhost_dev *dev,
141 struct vhost_work *work)
142{
Tejun Heoc23f3442010-06-02 20:40:00 +0200143 unsigned long flags;
144
145 spin_lock_irqsave(&dev->work_lock, flags);
146 if (list_empty(&work->node)) {
147 list_add_tail(&work->node, &dev->work_list);
148 work->queue_seq++;
149 wake_up_process(dev->worker);
150 }
151 spin_unlock_irqrestore(&dev->work_lock, flags);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000152}
153
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300154void vhost_poll_queue(struct vhost_poll *poll)
155{
156 vhost_work_queue(poll->dev, &poll->work);
157}
158
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000159static void vhost_vq_reset(struct vhost_dev *dev,
160 struct vhost_virtqueue *vq)
161{
162 vq->num = 1;
163 vq->desc = NULL;
164 vq->avail = NULL;
165 vq->used = NULL;
166 vq->last_avail_idx = 0;
167 vq->avail_idx = 0;
168 vq->last_used_idx = 0;
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300169 vq->signalled_used = 0;
170 vq->signalled_used_valid = false;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000171 vq->used_flags = 0;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000172 vq->log_used = false;
173 vq->log_addr = -1ull;
David Stevens8dd014a2010-07-27 18:52:21 +0300174 vq->vhost_hlen = 0;
175 vq->sock_hlen = 0;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000176 vq->private_data = NULL;
177 vq->log_base = NULL;
178 vq->error_ctx = NULL;
179 vq->error = NULL;
180 vq->kick = NULL;
181 vq->call_ctx = NULL;
182 vq->call = NULL;
Michael S. Tsirkin73a99f02010-02-23 11:23:45 +0200183 vq->log_ctx = NULL;
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000184 vq->upend_idx = 0;
185 vq->done_idx = 0;
186 vq->ubufs = NULL;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000187}
188
Tejun Heoc23f3442010-06-02 20:40:00 +0200189static int vhost_worker(void *data)
190{
191 struct vhost_dev *dev = data;
192 struct vhost_work *work = NULL;
193 unsigned uninitialized_var(seq);
194
Michael S. Tsirkin64e1c802010-10-06 15:34:45 +0200195 use_mm(dev->mm);
196
Tejun Heoc23f3442010-06-02 20:40:00 +0200197 for (;;) {
198 /* mb paired w/ kthread_stop */
199 set_current_state(TASK_INTERRUPTIBLE);
200
201 spin_lock_irq(&dev->work_lock);
202 if (work) {
203 work->done_seq = seq;
204 if (work->flushing)
205 wake_up_all(&work->done);
206 }
207
208 if (kthread_should_stop()) {
209 spin_unlock_irq(&dev->work_lock);
210 __set_current_state(TASK_RUNNING);
Michael S. Tsirkin64e1c802010-10-06 15:34:45 +0200211 break;
Tejun Heoc23f3442010-06-02 20:40:00 +0200212 }
213 if (!list_empty(&dev->work_list)) {
214 work = list_first_entry(&dev->work_list,
215 struct vhost_work, node);
216 list_del_init(&work->node);
217 seq = work->queue_seq;
218 } else
219 work = NULL;
220 spin_unlock_irq(&dev->work_lock);
221
222 if (work) {
223 __set_current_state(TASK_RUNNING);
224 work->fn(work);
225 } else
226 schedule();
227
228 }
Michael S. Tsirkin64e1c802010-10-06 15:34:45 +0200229 unuse_mm(dev->mm);
230 return 0;
Tejun Heoc23f3442010-06-02 20:40:00 +0200231}
232
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000233static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
234{
235 kfree(vq->indirect);
236 vq->indirect = NULL;
237 kfree(vq->log);
238 vq->log = NULL;
239 kfree(vq->heads);
240 vq->heads = NULL;
241 kfree(vq->ubuf_info);
242 vq->ubuf_info = NULL;
243}
244
245void vhost_enable_zcopy(int vq)
246{
247 vhost_zcopy_mask |= 0x1 << vq;
248}
249
Jason Wange0e9b402010-09-14 23:53:05 +0800250/* Helper to allocate iovec buffers for all vqs. */
251static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
252{
253 int i;
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000254 bool zcopy;
Krishna Kumard47effe2011-03-01 17:06:37 +0530255
Jason Wange0e9b402010-09-14 23:53:05 +0800256 for (i = 0; i < dev->nvqs; ++i) {
257 dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect *
258 UIO_MAXIOV, GFP_KERNEL);
259 dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV,
260 GFP_KERNEL);
261 dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads *
262 UIO_MAXIOV, GFP_KERNEL);
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000263 zcopy = vhost_zcopy_mask & (0x1 << i);
264 if (zcopy)
265 dev->vqs[i].ubuf_info =
266 kmalloc(sizeof *dev->vqs[i].ubuf_info *
267 UIO_MAXIOV, GFP_KERNEL);
Jason Wange0e9b402010-09-14 23:53:05 +0800268 if (!dev->vqs[i].indirect || !dev->vqs[i].log ||
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000269 !dev->vqs[i].heads ||
270 (zcopy && !dev->vqs[i].ubuf_info))
Jason Wange0e9b402010-09-14 23:53:05 +0800271 goto err_nomem;
272 }
273 return 0;
Krishna Kumard47effe2011-03-01 17:06:37 +0530274
Jason Wange0e9b402010-09-14 23:53:05 +0800275err_nomem:
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000276 for (; i >= 0; --i)
277 vhost_vq_free_iovecs(&dev->vqs[i]);
Jason Wange0e9b402010-09-14 23:53:05 +0800278 return -ENOMEM;
279}
280
281static void vhost_dev_free_iovecs(struct vhost_dev *dev)
282{
283 int i;
Krishna Kumard47effe2011-03-01 17:06:37 +0530284
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000285 for (i = 0; i < dev->nvqs; ++i)
286 vhost_vq_free_iovecs(&dev->vqs[i]);
Jason Wange0e9b402010-09-14 23:53:05 +0800287}
288
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000289long vhost_dev_init(struct vhost_dev *dev,
290 struct vhost_virtqueue *vqs, int nvqs)
291{
292 int i;
Tejun Heoc23f3442010-06-02 20:40:00 +0200293
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000294 dev->vqs = vqs;
295 dev->nvqs = nvqs;
296 mutex_init(&dev->mutex);
297 dev->log_ctx = NULL;
298 dev->log_file = NULL;
299 dev->memory = NULL;
300 dev->mm = NULL;
Tejun Heoc23f3442010-06-02 20:40:00 +0200301 spin_lock_init(&dev->work_lock);
302 INIT_LIST_HEAD(&dev->work_list);
303 dev->worker = NULL;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000304
305 for (i = 0; i < dev->nvqs; ++i) {
Jason Wange0e9b402010-09-14 23:53:05 +0800306 dev->vqs[i].log = NULL;
307 dev->vqs[i].indirect = NULL;
308 dev->vqs[i].heads = NULL;
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000309 dev->vqs[i].ubuf_info = NULL;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000310 dev->vqs[i].dev = dev;
311 mutex_init(&dev->vqs[i].mutex);
312 vhost_vq_reset(dev, dev->vqs + i);
313 if (dev->vqs[i].handle_kick)
314 vhost_poll_init(&dev->vqs[i].poll,
Tejun Heoc23f3442010-06-02 20:40:00 +0200315 dev->vqs[i].handle_kick, POLLIN, dev);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000316 }
Tejun Heoc23f3442010-06-02 20:40:00 +0200317
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000318 return 0;
319}
320
321/* Caller should have device mutex */
322long vhost_dev_check_owner(struct vhost_dev *dev)
323{
324 /* Are you the owner? If not, I don't think you mean to do that */
325 return dev->mm == current->mm ? 0 : -EPERM;
326}
327
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300328struct vhost_attach_cgroups_struct {
Krishna Kumard47effe2011-03-01 17:06:37 +0530329 struct vhost_work work;
330 struct task_struct *owner;
331 int ret;
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300332};
333
334static void vhost_attach_cgroups_work(struct vhost_work *work)
335{
Krishna Kumard47effe2011-03-01 17:06:37 +0530336 struct vhost_attach_cgroups_struct *s;
337
338 s = container_of(work, struct vhost_attach_cgroups_struct, work);
339 s->ret = cgroup_attach_task_all(s->owner, current);
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300340}
341
342static int vhost_attach_cgroups(struct vhost_dev *dev)
343{
Krishna Kumard47effe2011-03-01 17:06:37 +0530344 struct vhost_attach_cgroups_struct attach;
345
346 attach.owner = current;
347 vhost_work_init(&attach.work, vhost_attach_cgroups_work);
348 vhost_work_queue(dev, &attach.work);
349 vhost_work_flush(dev, &attach.work);
350 return attach.ret;
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300351}
352
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000353/* Caller should have device mutex */
354static long vhost_dev_set_owner(struct vhost_dev *dev)
355{
Tejun Heoc23f3442010-06-02 20:40:00 +0200356 struct task_struct *worker;
357 int err;
Krishna Kumard47effe2011-03-01 17:06:37 +0530358
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000359 /* Is there an owner already? */
Tejun Heoc23f3442010-06-02 20:40:00 +0200360 if (dev->mm) {
361 err = -EBUSY;
362 goto err_mm;
363 }
Krishna Kumard47effe2011-03-01 17:06:37 +0530364
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000365 /* No owner, become one */
366 dev->mm = get_task_mm(current);
Tejun Heoc23f3442010-06-02 20:40:00 +0200367 worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
368 if (IS_ERR(worker)) {
369 err = PTR_ERR(worker);
370 goto err_worker;
371 }
372
373 dev->worker = worker;
Michael S. Tsirkin87d6a412010-09-02 14:05:30 +0300374 wake_up_process(worker); /* avoid contributing to loadavg */
375
376 err = vhost_attach_cgroups(dev);
Michael S. Tsirkin9e3d1952010-07-27 22:56:50 +0300377 if (err)
378 goto err_cgroup;
Tejun Heoc23f3442010-06-02 20:40:00 +0200379
Jason Wange0e9b402010-09-14 23:53:05 +0800380 err = vhost_dev_alloc_iovecs(dev);
381 if (err)
382 goto err_cgroup;
383
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000384 return 0;
Michael S. Tsirkin9e3d1952010-07-27 22:56:50 +0300385err_cgroup:
386 kthread_stop(worker);
Michael S. Tsirkin615cc222010-09-02 14:16:36 +0300387 dev->worker = NULL;
Tejun Heoc23f3442010-06-02 20:40:00 +0200388err_worker:
389 if (dev->mm)
390 mmput(dev->mm);
391 dev->mm = NULL;
392err_mm:
393 return err;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000394}
395
396/* Caller should have device mutex */
397long vhost_dev_reset_owner(struct vhost_dev *dev)
398{
399 struct vhost_memory *memory;
400
401 /* Restore memory to default empty mapping. */
402 memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL);
403 if (!memory)
404 return -ENOMEM;
405
406 vhost_dev_cleanup(dev);
407
408 memory->nregions = 0;
Arnd Bergmann28457ee2010-03-09 19:24:45 +0100409 RCU_INIT_POINTER(dev->memory, memory);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000410 return 0;
411}
412
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000413/* In case of DMA done not in order in lower device driver for some reason.
414 * upend_idx is used to track end of used idx, done_idx is used to track head
415 * of used idx. Once lower device DMA done contiguously, we will signal KVM
416 * guest used idx.
417 */
418int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq)
419{
420 int i;
421 int j = 0;
422
423 for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
424 if ((vq->heads[i].len == VHOST_DMA_DONE_LEN)) {
425 vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
426 vhost_add_used_and_signal(vq->dev, vq,
427 vq->heads[i].id, 0);
428 ++j;
429 } else
430 break;
431 }
432 if (j)
433 vq->done_idx = i;
434 return j;
435}
436
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000437/* Caller should have device mutex */
438void vhost_dev_cleanup(struct vhost_dev *dev)
439{
440 int i;
Krishna Kumard47effe2011-03-01 17:06:37 +0530441
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000442 for (i = 0; i < dev->nvqs; ++i) {
443 if (dev->vqs[i].kick && dev->vqs[i].handle_kick) {
444 vhost_poll_stop(&dev->vqs[i].poll);
445 vhost_poll_flush(&dev->vqs[i].poll);
446 }
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +0000447 /* Wait for all lower device DMAs done. */
448 if (dev->vqs[i].ubufs)
449 vhost_ubuf_put_and_wait(dev->vqs[i].ubufs);
450
451 /* Signal guest as appropriate. */
452 vhost_zerocopy_signal_used(&dev->vqs[i]);
453
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000454 if (dev->vqs[i].error_ctx)
455 eventfd_ctx_put(dev->vqs[i].error_ctx);
456 if (dev->vqs[i].error)
457 fput(dev->vqs[i].error);
458 if (dev->vqs[i].kick)
459 fput(dev->vqs[i].kick);
460 if (dev->vqs[i].call_ctx)
461 eventfd_ctx_put(dev->vqs[i].call_ctx);
462 if (dev->vqs[i].call)
463 fput(dev->vqs[i].call);
464 vhost_vq_reset(dev, dev->vqs + i);
465 }
Jason Wange0e9b402010-09-14 23:53:05 +0800466 vhost_dev_free_iovecs(dev);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000467 if (dev->log_ctx)
468 eventfd_ctx_put(dev->log_ctx);
469 dev->log_ctx = NULL;
470 if (dev->log_file)
471 fput(dev->log_file);
472 dev->log_file = NULL;
473 /* No one will access memory at this point */
Arnd Bergmann28457ee2010-03-09 19:24:45 +0100474 kfree(rcu_dereference_protected(dev->memory,
475 lockdep_is_held(&dev->mutex)));
476 RCU_INIT_POINTER(dev->memory, NULL);
Tejun Heoc23f3442010-06-02 20:40:00 +0200477 WARN_ON(!list_empty(&dev->work_list));
Eric Dumazet78b620c2010-08-31 02:05:57 +0000478 if (dev->worker) {
479 kthread_stop(dev->worker);
480 dev->worker = NULL;
481 }
Michael S. Tsirkin533a19b2010-10-06 15:34:38 +0200482 if (dev->mm)
483 mmput(dev->mm);
484 dev->mm = NULL;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000485}
486
487static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
488{
489 u64 a = addr / VHOST_PAGE_SIZE / 8;
Krishna Kumard47effe2011-03-01 17:06:37 +0530490
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000491 /* Make sure 64 bit math will not overflow. */
492 if (a > ULONG_MAX - (unsigned long)log_base ||
493 a + (unsigned long)log_base > ULONG_MAX)
Dan Carpenter6d97e552010-10-11 19:24:19 +0200494 return 0;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000495
496 return access_ok(VERIFY_WRITE, log_base + a,
497 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
498}
499
500/* Caller should have vq mutex and device mutex. */
501static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem,
502 int log_all)
503{
504 int i;
Jeff Dike179b2842010-04-07 09:59:10 -0400505
Michael S. Tsirkinf8322fb2010-05-27 12:28:03 +0300506 if (!mem)
507 return 0;
Jeff Dike179b2842010-04-07 09:59:10 -0400508
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000509 for (i = 0; i < mem->nregions; ++i) {
510 struct vhost_memory_region *m = mem->regions + i;
511 unsigned long a = m->userspace_addr;
512 if (m->memory_size > ULONG_MAX)
513 return 0;
514 else if (!access_ok(VERIFY_WRITE, (void __user *)a,
515 m->memory_size))
516 return 0;
517 else if (log_all && !log_access_ok(log_base,
518 m->guest_phys_addr,
519 m->memory_size))
520 return 0;
521 }
522 return 1;
523}
524
525/* Can we switch to this memory table? */
526/* Caller should have device mutex but not vq mutex */
527static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem,
528 int log_all)
529{
530 int i;
Krishna Kumard47effe2011-03-01 17:06:37 +0530531
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000532 for (i = 0; i < d->nvqs; ++i) {
533 int ok;
534 mutex_lock(&d->vqs[i].mutex);
535 /* If ring is inactive, will check when it's enabled. */
536 if (d->vqs[i].private_data)
537 ok = vq_memory_access_ok(d->vqs[i].log_base, mem,
538 log_all);
539 else
540 ok = 1;
541 mutex_unlock(&d->vqs[i].mutex);
542 if (!ok)
543 return 0;
544 }
545 return 1;
546}
547
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300548static int vq_access_ok(struct vhost_dev *d, unsigned int num,
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000549 struct vring_desc __user *desc,
550 struct vring_avail __user *avail,
551 struct vring_used __user *used)
552{
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300553 size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000554 return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
555 access_ok(VERIFY_READ, avail,
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300556 sizeof *avail + num * sizeof *avail->ring + s) &&
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000557 access_ok(VERIFY_WRITE, used,
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300558 sizeof *used + num * sizeof *used->ring + s);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000559}
560
561/* Can we log writes? */
562/* Caller should have device mutex but not vq mutex */
563int vhost_log_access_ok(struct vhost_dev *dev)
564{
Arnd Bergmann28457ee2010-03-09 19:24:45 +0100565 struct vhost_memory *mp;
566
567 mp = rcu_dereference_protected(dev->memory,
568 lockdep_is_held(&dev->mutex));
569 return memory_access_ok(dev, mp, 1);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000570}
571
572/* Verify access for write logging. */
573/* Caller should have vq mutex and device mutex */
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300574static int vq_log_access_ok(struct vhost_dev *d, struct vhost_virtqueue *vq,
575 void __user *log_base)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000576{
Arnd Bergmann28457ee2010-03-09 19:24:45 +0100577 struct vhost_memory *mp;
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300578 size_t s = vhost_has_feature(d, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
Arnd Bergmann28457ee2010-03-09 19:24:45 +0100579
580 mp = rcu_dereference_protected(vq->dev->memory,
581 lockdep_is_held(&vq->mutex));
582 return vq_memory_access_ok(log_base, mp,
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000583 vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) &&
584 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
585 sizeof *vq->used +
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300586 vq->num * sizeof *vq->used->ring + s));
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000587}
588
589/* Can we start vq? */
590/* Caller should have vq mutex and device mutex */
591int vhost_vq_access_ok(struct vhost_virtqueue *vq)
592{
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300593 return vq_access_ok(vq->dev, vq->num, vq->desc, vq->avail, vq->used) &&
594 vq_log_access_ok(vq->dev, vq, vq->log_base);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000595}
596
597static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
598{
599 struct vhost_memory mem, *newmem, *oldmem;
600 unsigned long size = offsetof(struct vhost_memory, regions);
Krishna Kumard47effe2011-03-01 17:06:37 +0530601
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900602 if (copy_from_user(&mem, m, size))
603 return -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000604 if (mem.padding)
605 return -EOPNOTSUPP;
606 if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS)
607 return -E2BIG;
608 newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL);
609 if (!newmem)
610 return -ENOMEM;
611
612 memcpy(newmem, &mem, size);
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900613 if (copy_from_user(newmem->regions, m->regions,
614 mem.nregions * sizeof *m->regions)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000615 kfree(newmem);
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900616 return -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000617 }
618
Krishna Kumard47effe2011-03-01 17:06:37 +0530619 if (!memory_access_ok(d, newmem,
620 vhost_has_feature(d, VHOST_F_LOG_ALL))) {
Takuya Yoshikawaa02c3782010-05-27 19:03:56 +0900621 kfree(newmem);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000622 return -EFAULT;
Takuya Yoshikawaa02c3782010-05-27 19:03:56 +0900623 }
Arnd Bergmann28457ee2010-03-09 19:24:45 +0100624 oldmem = rcu_dereference_protected(d->memory,
625 lockdep_is_held(&d->mutex));
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000626 rcu_assign_pointer(d->memory, newmem);
627 synchronize_rcu();
628 kfree(oldmem);
629 return 0;
630}
631
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000632static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp)
633{
634 struct file *eventfp, *filep = NULL,
635 *pollstart = NULL, *pollstop = NULL;
636 struct eventfd_ctx *ctx = NULL;
637 u32 __user *idxp = argp;
638 struct vhost_virtqueue *vq;
639 struct vhost_vring_state s;
640 struct vhost_vring_file f;
641 struct vhost_vring_addr a;
642 u32 idx;
643 long r;
644
645 r = get_user(idx, idxp);
646 if (r < 0)
647 return r;
Krishna Kumar0f3d9a12010-05-25 11:10:36 +0530648 if (idx >= d->nvqs)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000649 return -ENOBUFS;
650
651 vq = d->vqs + idx;
652
653 mutex_lock(&vq->mutex);
654
655 switch (ioctl) {
656 case VHOST_SET_VRING_NUM:
657 /* Resizing ring with an active backend?
658 * You don't want to do that. */
659 if (vq->private_data) {
660 r = -EBUSY;
661 break;
662 }
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900663 if (copy_from_user(&s, argp, sizeof s)) {
664 r = -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000665 break;
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900666 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000667 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
668 r = -EINVAL;
669 break;
670 }
671 vq->num = s.num;
672 break;
673 case VHOST_SET_VRING_BASE:
674 /* Moving base with an active backend?
675 * You don't want to do that. */
676 if (vq->private_data) {
677 r = -EBUSY;
678 break;
679 }
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900680 if (copy_from_user(&s, argp, sizeof s)) {
681 r = -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000682 break;
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900683 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000684 if (s.num > 0xffff) {
685 r = -EINVAL;
686 break;
687 }
688 vq->last_avail_idx = s.num;
689 /* Forget the cached index value. */
690 vq->avail_idx = vq->last_avail_idx;
691 break;
692 case VHOST_GET_VRING_BASE:
693 s.index = idx;
694 s.num = vq->last_avail_idx;
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900695 if (copy_to_user(argp, &s, sizeof s))
696 r = -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000697 break;
698 case VHOST_SET_VRING_ADDR:
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900699 if (copy_from_user(&a, argp, sizeof a)) {
700 r = -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000701 break;
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900702 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000703 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
704 r = -EOPNOTSUPP;
705 break;
706 }
707 /* For 32bit, verify that the top 32bits of the user
708 data are set to zero. */
709 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
710 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
711 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
712 r = -EFAULT;
713 break;
714 }
715 if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) ||
716 (a.used_user_addr & (sizeof *vq->used->ring - 1)) ||
717 (a.log_guest_addr & (sizeof *vq->used->ring - 1))) {
718 r = -EINVAL;
719 break;
720 }
721
722 /* We only verify access here if backend is configured.
723 * If it is not, we don't as size might not have been setup.
724 * We will verify when backend is configured. */
725 if (vq->private_data) {
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300726 if (!vq_access_ok(d, vq->num,
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000727 (void __user *)(unsigned long)a.desc_user_addr,
728 (void __user *)(unsigned long)a.avail_user_addr,
729 (void __user *)(unsigned long)a.used_user_addr)) {
730 r = -EINVAL;
731 break;
732 }
733
734 /* Also validate log access for used ring if enabled. */
735 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
736 !log_access_ok(vq->log_base, a.log_guest_addr,
737 sizeof *vq->used +
738 vq->num * sizeof *vq->used->ring)) {
739 r = -EINVAL;
740 break;
741 }
742 }
743
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000744 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
745 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
746 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
747 vq->log_addr = a.log_guest_addr;
748 vq->used = (void __user *)(unsigned long)a.used_user_addr;
749 break;
750 case VHOST_SET_VRING_KICK:
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900751 if (copy_from_user(&f, argp, sizeof f)) {
752 r = -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000753 break;
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900754 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000755 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
Michael S. Tsirkin535297a2010-03-17 16:06:11 +0200756 if (IS_ERR(eventfp)) {
757 r = PTR_ERR(eventfp);
758 break;
759 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000760 if (eventfp != vq->kick) {
761 pollstop = filep = vq->kick;
762 pollstart = vq->kick = eventfp;
763 } else
764 filep = eventfp;
765 break;
766 case VHOST_SET_VRING_CALL:
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900767 if (copy_from_user(&f, argp, sizeof f)) {
768 r = -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000769 break;
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900770 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000771 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
Michael S. Tsirkin535297a2010-03-17 16:06:11 +0200772 if (IS_ERR(eventfp)) {
773 r = PTR_ERR(eventfp);
774 break;
775 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000776 if (eventfp != vq->call) {
777 filep = vq->call;
778 ctx = vq->call_ctx;
779 vq->call = eventfp;
780 vq->call_ctx = eventfp ?
781 eventfd_ctx_fileget(eventfp) : NULL;
782 } else
783 filep = eventfp;
784 break;
785 case VHOST_SET_VRING_ERR:
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900786 if (copy_from_user(&f, argp, sizeof f)) {
787 r = -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000788 break;
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900789 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000790 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
Michael S. Tsirkin535297a2010-03-17 16:06:11 +0200791 if (IS_ERR(eventfp)) {
792 r = PTR_ERR(eventfp);
793 break;
794 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000795 if (eventfp != vq->error) {
796 filep = vq->error;
797 vq->error = eventfp;
798 ctx = vq->error_ctx;
799 vq->error_ctx = eventfp ?
800 eventfd_ctx_fileget(eventfp) : NULL;
801 } else
802 filep = eventfp;
803 break;
804 default:
805 r = -ENOIOCTLCMD;
806 }
807
808 if (pollstop && vq->handle_kick)
809 vhost_poll_stop(&vq->poll);
810
811 if (ctx)
812 eventfd_ctx_put(ctx);
813 if (filep)
814 fput(filep);
815
816 if (pollstart && vq->handle_kick)
817 vhost_poll_start(&vq->poll, vq->kick);
818
819 mutex_unlock(&vq->mutex);
820
821 if (pollstop && vq->handle_kick)
822 vhost_poll_flush(&vq->poll);
823 return r;
824}
825
826/* Caller must have device mutex */
827long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg)
828{
829 void __user *argp = (void __user *)arg;
830 struct file *eventfp, *filep = NULL;
831 struct eventfd_ctx *ctx = NULL;
832 u64 p;
833 long r;
834 int i, fd;
835
836 /* If you are not the owner, you can become one */
837 if (ioctl == VHOST_SET_OWNER) {
838 r = vhost_dev_set_owner(d);
839 goto done;
840 }
841
842 /* You must be the owner to do anything else */
843 r = vhost_dev_check_owner(d);
844 if (r)
845 goto done;
846
847 switch (ioctl) {
848 case VHOST_SET_MEM_TABLE:
849 r = vhost_set_memory(d, argp);
850 break;
851 case VHOST_SET_LOG_BASE:
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900852 if (copy_from_user(&p, argp, sizeof p)) {
853 r = -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000854 break;
Takuya Yoshikawa7ad9c9d2010-05-27 18:58:03 +0900855 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000856 if ((u64)(unsigned long)p != p) {
857 r = -EFAULT;
858 break;
859 }
860 for (i = 0; i < d->nvqs; ++i) {
861 struct vhost_virtqueue *vq;
862 void __user *base = (void __user *)(unsigned long)p;
863 vq = d->vqs + i;
864 mutex_lock(&vq->mutex);
865 /* If ring is inactive, will check when it's enabled. */
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +0300866 if (vq->private_data && !vq_log_access_ok(d, vq, base))
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000867 r = -EFAULT;
868 else
869 vq->log_base = base;
870 mutex_unlock(&vq->mutex);
871 }
872 break;
873 case VHOST_SET_LOG_FD:
874 r = get_user(fd, (int __user *)argp);
875 if (r < 0)
876 break;
877 eventfp = fd == -1 ? NULL : eventfd_fget(fd);
878 if (IS_ERR(eventfp)) {
879 r = PTR_ERR(eventfp);
880 break;
881 }
882 if (eventfp != d->log_file) {
883 filep = d->log_file;
884 ctx = d->log_ctx;
885 d->log_ctx = eventfp ?
886 eventfd_ctx_fileget(eventfp) : NULL;
887 } else
888 filep = eventfp;
889 for (i = 0; i < d->nvqs; ++i) {
890 mutex_lock(&d->vqs[i].mutex);
891 d->vqs[i].log_ctx = d->log_ctx;
892 mutex_unlock(&d->vqs[i].mutex);
893 }
894 if (ctx)
895 eventfd_ctx_put(ctx);
896 if (filep)
897 fput(filep);
898 break;
899 default:
900 r = vhost_set_vring(d, ioctl, argp);
901 break;
902 }
903done:
904 return r;
905}
906
907static const struct vhost_memory_region *find_region(struct vhost_memory *mem,
908 __u64 addr, __u32 len)
909{
910 struct vhost_memory_region *reg;
911 int i;
Krishna Kumard47effe2011-03-01 17:06:37 +0530912
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000913 /* linear search is not brilliant, but we really have on the order of 6
914 * regions in practice */
915 for (i = 0; i < mem->nregions; ++i) {
916 reg = mem->regions + i;
917 if (reg->guest_phys_addr <= addr &&
918 reg->guest_phys_addr + reg->memory_size - 1 >= addr)
919 return reg;
920 }
921 return NULL;
922}
923
924/* TODO: This is really inefficient. We need something like get_user()
925 * (instruction directly accesses the data, with an exception table entry
926 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
927 */
928static int set_bit_to_user(int nr, void __user *addr)
929{
930 unsigned long log = (unsigned long)addr;
931 struct page *page;
932 void *base;
933 int bit = nr + (log % PAGE_SIZE) * 8;
934 int r;
Krishna Kumard47effe2011-03-01 17:06:37 +0530935
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000936 r = get_user_pages_fast(log, 1, 1, &page);
Michael S. Tsirkind6db3f52010-02-23 11:25:23 +0200937 if (r < 0)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000938 return r;
Michael S. Tsirkind6db3f52010-02-23 11:25:23 +0200939 BUG_ON(r != 1);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000940 base = kmap_atomic(page, KM_USER0);
941 set_bit(bit, base);
942 kunmap_atomic(base, KM_USER0);
943 set_page_dirty_lock(page);
944 put_page(page);
945 return 0;
946}
947
948static int log_write(void __user *log_base,
949 u64 write_address, u64 write_length)
950{
Michael S. Tsirkin28831ee2010-11-29 10:22:10 +0200951 u64 write_page = write_address / VHOST_PAGE_SIZE;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000952 int r;
Krishna Kumard47effe2011-03-01 17:06:37 +0530953
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000954 if (!write_length)
955 return 0;
Michael S. Tsirkin3bf9be42010-11-29 10:19:07 +0200956 write_length += write_address % VHOST_PAGE_SIZE;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000957 for (;;) {
958 u64 base = (u64)(unsigned long)log_base;
Michael S. Tsirkin28831ee2010-11-29 10:22:10 +0200959 u64 log = base + write_page / 8;
960 int bit = write_page % 8;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000961 if ((u64)(unsigned long)log != log)
962 return -EFAULT;
963 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
964 if (r < 0)
965 return r;
966 if (write_length <= VHOST_PAGE_SIZE)
967 break;
968 write_length -= VHOST_PAGE_SIZE;
Michael S. Tsirkin28831ee2010-11-29 10:22:10 +0200969 write_page += 1;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000970 }
971 return r;
972}
973
974int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
975 unsigned int log_num, u64 len)
976{
977 int i, r;
978
979 /* Make sure data written is seen before log. */
Michael S. Tsirkin56593382010-02-01 07:21:02 +0000980 smp_wmb();
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000981 for (i = 0; i < log_num; ++i) {
982 u64 l = min(log[i].len, len);
983 r = log_write(vq->log_base, log[i].addr, l);
984 if (r < 0)
985 return r;
986 len -= l;
Michael S. Tsirkin5786aee2010-09-22 12:31:53 +0200987 if (!len) {
988 if (vq->log_ctx)
989 eventfd_signal(vq->log_ctx, 1);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000990 return 0;
Michael S. Tsirkin5786aee2010-09-22 12:31:53 +0200991 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000992 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +0000993 /* Length written exceeds what we have stored. This is a bug. */
994 BUG();
995 return 0;
996}
997
Jason Wang2723fea2011-06-21 18:04:38 +0800998static int vhost_update_used_flags(struct vhost_virtqueue *vq)
999{
1000 void __user *used;
Michael S. Tsirkinb8342262011-07-19 17:15:43 +03001001 if (__put_user(vq->used_flags, &vq->used->flags) < 0)
Jason Wang2723fea2011-06-21 18:04:38 +08001002 return -EFAULT;
1003 if (unlikely(vq->log_used)) {
1004 /* Make sure the flag is seen before log. */
1005 smp_wmb();
1006 /* Log used flag write. */
1007 used = &vq->used->flags;
1008 log_write(vq->log_base, vq->log_addr +
1009 (used - (void __user *)vq->used),
1010 sizeof vq->used->flags);
1011 if (vq->log_ctx)
1012 eventfd_signal(vq->log_ctx, 1);
1013 }
1014 return 0;
1015}
1016
1017static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1018{
Michael S. Tsirkinb8342262011-07-19 17:15:43 +03001019 if (__put_user(vq->avail_idx, vhost_avail_event(vq)))
Jason Wang2723fea2011-06-21 18:04:38 +08001020 return -EFAULT;
1021 if (unlikely(vq->log_used)) {
1022 void __user *used;
1023 /* Make sure the event is seen before log. */
1024 smp_wmb();
1025 /* Log avail event write */
1026 used = vhost_avail_event(vq);
1027 log_write(vq->log_base, vq->log_addr +
1028 (used - (void __user *)vq->used),
1029 sizeof *vhost_avail_event(vq));
1030 if (vq->log_ctx)
1031 eventfd_signal(vq->log_ctx, 1);
1032 }
1033 return 0;
1034}
1035
1036int vhost_init_used(struct vhost_virtqueue *vq)
1037{
1038 int r;
1039 if (!vq->private_data)
1040 return 0;
1041
1042 r = vhost_update_used_flags(vq);
1043 if (r)
1044 return r;
1045 vq->signalled_used_valid = false;
1046 return get_user(vq->last_used_idx, &vq->used->idx);
1047}
1048
Christoph Hellwiga8d37822010-04-13 14:11:25 -04001049static int translate_desc(struct vhost_dev *dev, u64 addr, u32 len,
1050 struct iovec iov[], int iov_size)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001051{
1052 const struct vhost_memory_region *reg;
1053 struct vhost_memory *mem;
1054 struct iovec *_iov;
1055 u64 s = 0;
1056 int ret = 0;
1057
1058 rcu_read_lock();
1059
1060 mem = rcu_dereference(dev->memory);
1061 while ((u64)len > s) {
1062 u64 size;
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001063 if (unlikely(ret >= iov_size)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001064 ret = -ENOBUFS;
1065 break;
1066 }
1067 reg = find_region(mem, addr, len);
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001068 if (unlikely(!reg)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001069 ret = -EFAULT;
1070 break;
1071 }
1072 _iov = iov + ret;
1073 size = reg->memory_size - addr + reg->guest_phys_addr;
1074 _iov->iov_len = min((u64)len, size);
Christoph Hellwiga8d37822010-04-13 14:11:25 -04001075 _iov->iov_base = (void __user *)(unsigned long)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001076 (reg->userspace_addr + addr - reg->guest_phys_addr);
1077 s += size;
1078 addr += size;
1079 ++ret;
1080 }
1081
1082 rcu_read_unlock();
1083 return ret;
1084}
1085
1086/* Each buffer in the virtqueues is actually a chain of descriptors. This
1087 * function returns the next descriptor in the chain,
1088 * or -1U if we're at the end. */
1089static unsigned next_desc(struct vring_desc *desc)
1090{
1091 unsigned int next;
1092
1093 /* If this descriptor says it doesn't chain, we're done. */
1094 if (!(desc->flags & VRING_DESC_F_NEXT))
1095 return -1U;
1096
1097 /* Check they're not leading us off end of descriptors. */
1098 next = desc->next;
1099 /* Make sure compiler knows to grab that: we don't want it changing! */
1100 /* We will use the result as an index in an array, so most
1101 * architectures only need a compiler barrier here. */
1102 read_barrier_depends();
1103
1104 return next;
1105}
1106
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001107static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq,
1108 struct iovec iov[], unsigned int iov_size,
1109 unsigned int *out_num, unsigned int *in_num,
1110 struct vhost_log *log, unsigned int *log_num,
1111 struct vring_desc *indirect)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001112{
1113 struct vring_desc desc;
1114 unsigned int i = 0, count, found = 0;
1115 int ret;
1116
1117 /* Sanity check */
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001118 if (unlikely(indirect->len % sizeof desc)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001119 vq_err(vq, "Invalid length in indirect descriptor: "
1120 "len 0x%llx not multiple of 0x%zx\n",
1121 (unsigned long long)indirect->len,
1122 sizeof desc);
1123 return -EINVAL;
1124 }
1125
1126 ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect,
Jason Wange0e9b402010-09-14 23:53:05 +08001127 UIO_MAXIOV);
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001128 if (unlikely(ret < 0)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001129 vq_err(vq, "Translation failure %d in indirect.\n", ret);
1130 return ret;
1131 }
1132
1133 /* We will use the result as an address to read from, so most
1134 * architectures only need a compiler barrier here. */
1135 read_barrier_depends();
1136
1137 count = indirect->len / sizeof desc;
1138 /* Buffers are chained via a 16 bit next field, so
1139 * we can have at most 2^16 of these. */
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001140 if (unlikely(count > USHRT_MAX + 1)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001141 vq_err(vq, "Indirect buffer length too big: %d\n",
1142 indirect->len);
1143 return -E2BIG;
1144 }
1145
1146 do {
1147 unsigned iov_count = *in_num + *out_num;
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001148 if (unlikely(++found > count)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001149 vq_err(vq, "Loop detected: last one at %u "
1150 "indirect size %u\n",
1151 i, count);
1152 return -EINVAL;
1153 }
Krishna Kumard47effe2011-03-01 17:06:37 +05301154 if (unlikely(memcpy_fromiovec((unsigned char *)&desc,
1155 vq->indirect, sizeof desc))) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001156 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
1157 i, (size_t)indirect->addr + i * sizeof desc);
1158 return -EINVAL;
1159 }
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001160 if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001161 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
1162 i, (size_t)indirect->addr + i * sizeof desc);
1163 return -EINVAL;
1164 }
1165
1166 ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count,
1167 iov_size - iov_count);
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001168 if (unlikely(ret < 0)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001169 vq_err(vq, "Translation failure %d indirect idx %d\n",
1170 ret, i);
1171 return ret;
1172 }
1173 /* If this is an input descriptor, increment that count. */
1174 if (desc.flags & VRING_DESC_F_WRITE) {
1175 *in_num += ret;
1176 if (unlikely(log)) {
1177 log[*log_num].addr = desc.addr;
1178 log[*log_num].len = desc.len;
1179 ++*log_num;
1180 }
1181 } else {
1182 /* If it's an output descriptor, they're all supposed
1183 * to come before any input descriptors. */
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001184 if (unlikely(*in_num)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001185 vq_err(vq, "Indirect descriptor "
1186 "has out after in: idx %d\n", i);
1187 return -EINVAL;
1188 }
1189 *out_num += ret;
1190 }
1191 } while ((i = next_desc(&desc)) != -1);
1192 return 0;
1193}
1194
1195/* This looks in the virtqueue and for the first available buffer, and converts
1196 * it to an iovec for convenient access. Since descriptors consist of some
1197 * number of output then some number of input descriptors, it's actually two
1198 * iovecs, but we pack them into one and note how many of each there were.
1199 *
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001200 * This function returns the descriptor number found, or vq->num (which is
1201 * never a valid descriptor number) if none was found. A negative code is
1202 * returned on error. */
1203int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
1204 struct iovec iov[], unsigned int iov_size,
1205 unsigned int *out_num, unsigned int *in_num,
1206 struct vhost_log *log, unsigned int *log_num)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001207{
1208 struct vring_desc desc;
1209 unsigned int i, head, found = 0;
1210 u16 last_avail_idx;
1211 int ret;
1212
1213 /* Check it isn't doing very strange things with descriptor numbers. */
1214 last_avail_idx = vq->last_avail_idx;
Michael S. Tsirkin8b7347a2010-09-19 15:56:30 +02001215 if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001216 vq_err(vq, "Failed to access avail idx at %p\n",
1217 &vq->avail->idx);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001218 return -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001219 }
1220
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001221 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001222 vq_err(vq, "Guest moved used index from %u to %u",
1223 last_avail_idx, vq->avail_idx);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001224 return -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001225 }
1226
1227 /* If there's nothing new since last we looked, return invalid. */
1228 if (vq->avail_idx == last_avail_idx)
1229 return vq->num;
1230
1231 /* Only get avail ring entries after they have been exposed by guest. */
Michael S. Tsirkin56593382010-02-01 07:21:02 +00001232 smp_rmb();
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001233
1234 /* Grab the next descriptor number they're advertising, and increment
1235 * the index we've seen. */
Michael S. Tsirkin8b7347a2010-09-19 15:56:30 +02001236 if (unlikely(__get_user(head,
1237 &vq->avail->ring[last_avail_idx % vq->num]))) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001238 vq_err(vq, "Failed to read head: idx %d address %p\n",
1239 last_avail_idx,
1240 &vq->avail->ring[last_avail_idx % vq->num]);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001241 return -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001242 }
1243
1244 /* If their number is silly, that's an error. */
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001245 if (unlikely(head >= vq->num)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001246 vq_err(vq, "Guest says index %u > %u is available",
1247 head, vq->num);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001248 return -EINVAL;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001249 }
1250
1251 /* When we start there are none of either input nor output. */
1252 *out_num = *in_num = 0;
1253 if (unlikely(log))
1254 *log_num = 0;
1255
1256 i = head;
1257 do {
1258 unsigned iov_count = *in_num + *out_num;
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001259 if (unlikely(i >= vq->num)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001260 vq_err(vq, "Desc index is %u > %u, head = %u",
1261 i, vq->num, head);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001262 return -EINVAL;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001263 }
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001264 if (unlikely(++found > vq->num)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001265 vq_err(vq, "Loop detected: last one at %u "
1266 "vq size %u head %u\n",
1267 i, vq->num, head);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001268 return -EINVAL;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001269 }
Michael S. Tsirkinfcc042a2011-03-06 13:33:49 +02001270 ret = __copy_from_user(&desc, vq->desc + i, sizeof desc);
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001271 if (unlikely(ret)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001272 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
1273 i, vq->desc + i);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001274 return -EFAULT;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001275 }
1276 if (desc.flags & VRING_DESC_F_INDIRECT) {
1277 ret = get_indirect(dev, vq, iov, iov_size,
1278 out_num, in_num,
1279 log, log_num, &desc);
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001280 if (unlikely(ret < 0)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001281 vq_err(vq, "Failure detected "
1282 "in indirect descriptor at idx %d\n", i);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001283 return ret;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001284 }
1285 continue;
1286 }
1287
1288 ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count,
1289 iov_size - iov_count);
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001290 if (unlikely(ret < 0)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001291 vq_err(vq, "Translation failure %d descriptor idx %d\n",
1292 ret, i);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001293 return ret;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001294 }
1295 if (desc.flags & VRING_DESC_F_WRITE) {
1296 /* If this is an input descriptor,
1297 * increment that count. */
1298 *in_num += ret;
1299 if (unlikely(log)) {
1300 log[*log_num].addr = desc.addr;
1301 log[*log_num].len = desc.len;
1302 ++*log_num;
1303 }
1304 } else {
1305 /* If it's an output descriptor, they're all supposed
1306 * to come before any input descriptors. */
Michael S. Tsirkin7b3384f2010-07-01 18:40:12 +03001307 if (unlikely(*in_num)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001308 vq_err(vq, "Descriptor has out after in: "
1309 "idx %d\n", i);
Michael S. Tsirkind5675bd2010-06-24 16:59:59 +03001310 return -EINVAL;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001311 }
1312 *out_num += ret;
1313 }
1314 } while ((i = next_desc(&desc)) != -1);
1315
1316 /* On success, increment avail index. */
1317 vq->last_avail_idx++;
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001318
1319 /* Assume notifications from guest are disabled at this point,
1320 * if they aren't we would need to update avail_event index. */
1321 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001322 return head;
1323}
1324
1325/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
David Stevens8dd014a2010-07-27 18:52:21 +03001326void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001327{
David Stevens8dd014a2010-07-27 18:52:21 +03001328 vq->last_avail_idx -= n;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001329}
1330
1331/* After we've used one of their buffers, we tell them about it. We'll then
1332 * want to notify the guest, using eventfd. */
1333int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
1334{
Christoph Hellwiga8d37822010-04-13 14:11:25 -04001335 struct vring_used_elem __user *used;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001336
1337 /* The virtqueue contains a ring of used buffers. Get a pointer to the
1338 * next entry in that used ring. */
1339 used = &vq->used->ring[vq->last_used_idx % vq->num];
Michael S. Tsirkin8b7347a2010-09-19 15:56:30 +02001340 if (__put_user(head, &used->id)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001341 vq_err(vq, "Failed to write used id");
1342 return -EFAULT;
1343 }
Michael S. Tsirkin8b7347a2010-09-19 15:56:30 +02001344 if (__put_user(len, &used->len)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001345 vq_err(vq, "Failed to write used len");
1346 return -EFAULT;
1347 }
1348 /* Make sure buffer is written before we update index. */
Michael S. Tsirkin56593382010-02-01 07:21:02 +00001349 smp_wmb();
Michael S. Tsirkin8b7347a2010-09-19 15:56:30 +02001350 if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) {
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001351 vq_err(vq, "Failed to increment used idx");
1352 return -EFAULT;
1353 }
1354 if (unlikely(vq->log_used)) {
1355 /* Make sure data is seen before log. */
Michael S. Tsirkin56593382010-02-01 07:21:02 +00001356 smp_wmb();
Michael S. Tsirkin86e94242010-02-17 19:11:33 +02001357 /* Log used ring entry write. */
1358 log_write(vq->log_base,
Christoph Hellwiga8d37822010-04-13 14:11:25 -04001359 vq->log_addr +
1360 ((void __user *)used - (void __user *)vq->used),
Michael S. Tsirkin86e94242010-02-17 19:11:33 +02001361 sizeof *used);
1362 /* Log used index update. */
1363 log_write(vq->log_base,
1364 vq->log_addr + offsetof(struct vring_used, idx),
1365 sizeof vq->used->idx);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001366 if (vq->log_ctx)
1367 eventfd_signal(vq->log_ctx, 1);
1368 }
1369 vq->last_used_idx++;
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001370 /* If the driver never bothers to signal in a very long while,
1371 * used index might wrap around. If that happens, invalidate
1372 * signalled_used index we stored. TODO: make sure driver
1373 * signals at least once in 2^16 and remove this. */
1374 if (unlikely(vq->last_used_idx == vq->signalled_used))
1375 vq->signalled_used_valid = false;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001376 return 0;
1377}
1378
David Stevens8dd014a2010-07-27 18:52:21 +03001379static int __vhost_add_used_n(struct vhost_virtqueue *vq,
1380 struct vring_used_elem *heads,
1381 unsigned count)
1382{
1383 struct vring_used_elem __user *used;
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001384 u16 old, new;
David Stevens8dd014a2010-07-27 18:52:21 +03001385 int start;
1386
1387 start = vq->last_used_idx % vq->num;
1388 used = vq->used->ring + start;
Michael S. Tsirkindfe5ac52010-09-21 14:18:01 +02001389 if (__copy_to_user(used, heads, count * sizeof *used)) {
David Stevens8dd014a2010-07-27 18:52:21 +03001390 vq_err(vq, "Failed to write used");
1391 return -EFAULT;
1392 }
1393 if (unlikely(vq->log_used)) {
1394 /* Make sure data is seen before log. */
1395 smp_wmb();
1396 /* Log used ring entry write. */
1397 log_write(vq->log_base,
1398 vq->log_addr +
1399 ((void __user *)used - (void __user *)vq->used),
1400 count * sizeof *used);
1401 }
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001402 old = vq->last_used_idx;
1403 new = (vq->last_used_idx += count);
1404 /* If the driver never bothers to signal in a very long while,
1405 * used index might wrap around. If that happens, invalidate
1406 * signalled_used index we stored. TODO: make sure driver
1407 * signals at least once in 2^16 and remove this. */
1408 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
1409 vq->signalled_used_valid = false;
David Stevens8dd014a2010-07-27 18:52:21 +03001410 return 0;
1411}
1412
1413/* After we've used one of their buffers, we tell them about it. We'll then
1414 * want to notify the guest, using eventfd. */
1415int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
1416 unsigned count)
1417{
1418 int start, n, r;
1419
1420 start = vq->last_used_idx % vq->num;
1421 n = vq->num - start;
1422 if (n < count) {
1423 r = __vhost_add_used_n(vq, heads, n);
1424 if (r < 0)
1425 return r;
1426 heads += n;
1427 count -= n;
1428 }
1429 r = __vhost_add_used_n(vq, heads, count);
1430
1431 /* Make sure buffer is written before we update index. */
1432 smp_wmb();
1433 if (put_user(vq->last_used_idx, &vq->used->idx)) {
1434 vq_err(vq, "Failed to increment used idx");
1435 return -EFAULT;
1436 }
1437 if (unlikely(vq->log_used)) {
1438 /* Log used index update. */
1439 log_write(vq->log_base,
1440 vq->log_addr + offsetof(struct vring_used, idx),
1441 sizeof vq->used->idx);
1442 if (vq->log_ctx)
1443 eventfd_signal(vq->log_ctx, 1);
1444 }
1445 return r;
1446}
1447
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001448static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001449{
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001450 __u16 old, new, event;
1451 bool v;
Michael S. Tsirkin0d499352010-05-11 19:44:17 +03001452 /* Flush out used index updates. This is paired
1453 * with the barrier that the Guest executes when enabling
1454 * interrupts. */
1455 smp_mb();
1456
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001457 if (vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
1458 unlikely(vq->avail_idx == vq->last_avail_idx))
1459 return true;
1460
1461 if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
1462 __u16 flags;
1463 if (__get_user(flags, &vq->avail->flags)) {
1464 vq_err(vq, "Failed to get flags");
1465 return true;
1466 }
1467 return !(flags & VRING_AVAIL_F_NO_INTERRUPT);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001468 }
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001469 old = vq->signalled_used;
1470 v = vq->signalled_used_valid;
1471 new = vq->signalled_used = vq->last_used_idx;
1472 vq->signalled_used_valid = true;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001473
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001474 if (unlikely(!v))
1475 return true;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001476
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001477 if (get_user(event, vhost_used_event(vq))) {
1478 vq_err(vq, "Failed to get used event idx");
1479 return true;
1480 }
1481 return vring_need_event(event, new, old);
1482}
1483
1484/* This actually signals the guest, using eventfd. */
1485void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
1486{
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001487 /* Signal the Guest tell them we used something up. */
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001488 if (vq->call_ctx && vhost_notify(dev, vq))
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001489 eventfd_signal(vq->call_ctx, 1);
1490}
1491
1492/* And here's the combo meal deal. Supersize me! */
1493void vhost_add_used_and_signal(struct vhost_dev *dev,
1494 struct vhost_virtqueue *vq,
1495 unsigned int head, int len)
1496{
1497 vhost_add_used(vq, head, len);
1498 vhost_signal(dev, vq);
1499}
1500
David Stevens8dd014a2010-07-27 18:52:21 +03001501/* multi-buffer version of vhost_add_used_and_signal */
1502void vhost_add_used_and_signal_n(struct vhost_dev *dev,
1503 struct vhost_virtqueue *vq,
1504 struct vring_used_elem *heads, unsigned count)
1505{
1506 vhost_add_used_n(vq, heads, count);
1507 vhost_signal(dev, vq);
1508}
1509
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001510/* OK, now we need to know about added descriptors. */
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001511bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001512{
1513 u16 avail_idx;
1514 int r;
Krishna Kumard47effe2011-03-01 17:06:37 +05301515
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001516 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
1517 return false;
1518 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001519 if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
Jason Wang2723fea2011-06-21 18:04:38 +08001520 r = vhost_update_used_flags(vq);
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001521 if (r) {
1522 vq_err(vq, "Failed to enable notification at %p: %d\n",
1523 &vq->used->flags, r);
1524 return false;
1525 }
1526 } else {
Jason Wang2723fea2011-06-21 18:04:38 +08001527 r = vhost_update_avail_event(vq, vq->avail_idx);
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001528 if (r) {
1529 vq_err(vq, "Failed to update avail event index at %p: %d\n",
1530 vhost_avail_event(vq), r);
1531 return false;
1532 }
1533 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001534 /* They could have slipped one in as we were doing that: make
1535 * sure it's written, then check again. */
Michael S. Tsirkin56593382010-02-01 07:21:02 +00001536 smp_mb();
Michael S. Tsirkin8b7347a2010-09-19 15:56:30 +02001537 r = __get_user(avail_idx, &vq->avail->idx);
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001538 if (r) {
1539 vq_err(vq, "Failed to check avail idx at %p: %d\n",
1540 &vq->avail->idx, r);
1541 return false;
1542 }
1543
David Stevens8dd014a2010-07-27 18:52:21 +03001544 return avail_idx != vq->avail_idx;
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001545}
1546
1547/* We don't need to be notified again. */
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001548void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001549{
1550 int r;
Krishna Kumard47effe2011-03-01 17:06:37 +05301551
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001552 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
1553 return;
1554 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001555 if (!vhost_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
Jason Wang2723fea2011-06-21 18:04:38 +08001556 r = vhost_update_used_flags(vq);
Michael S. Tsirkin8ea8cf82011-05-20 02:10:54 +03001557 if (r)
1558 vq_err(vq, "Failed to enable notification at %p: %d\n",
1559 &vq->used->flags, r);
1560 }
Michael S. Tsirkin3a4d5c92010-01-14 06:17:27 +00001561}
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +00001562
1563static void vhost_zerocopy_done_signal(struct kref *kref)
1564{
1565 struct vhost_ubuf_ref *ubufs = container_of(kref, struct vhost_ubuf_ref,
1566 kref);
1567 wake_up(&ubufs->wait);
1568}
1569
1570struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq,
1571 bool zcopy)
1572{
1573 struct vhost_ubuf_ref *ubufs;
1574 /* No zero copy backend? Nothing to count. */
1575 if (!zcopy)
1576 return NULL;
1577 ubufs = kmalloc(sizeof *ubufs, GFP_KERNEL);
1578 if (!ubufs)
1579 return ERR_PTR(-ENOMEM);
1580 kref_init(&ubufs->kref);
Michael S. Tsirkinbab632d2011-07-18 03:48:46 +00001581 init_waitqueue_head(&ubufs->wait);
1582 ubufs->vq = vq;
1583 return ubufs;
1584}
1585
1586void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs)
1587{
1588 kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
1589}
1590
1591void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs)
1592{
1593 kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
1594 wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount));
1595 kfree(ubufs);
1596}
1597
1598void vhost_zerocopy_callback(void *arg)
1599{
1600 struct ubuf_info *ubuf = arg;
1601 struct vhost_ubuf_ref *ubufs = ubuf->arg;
1602 struct vhost_virtqueue *vq = ubufs->vq;
1603
1604 /* set len = 1 to mark this desc buffers done DMA */
1605 vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN;
1606 kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
1607}