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-rw-r--r--drivers/Makefile1
-rw-r--r--drivers/vhost/Kconfig11
-rw-r--r--drivers/vhost/Makefile2
-rw-r--r--drivers/vhost/net.c661
-rw-r--r--drivers/vhost/vhost.c1098
-rw-r--r--drivers/vhost/vhost.h161
6 files changed, 1934 insertions, 0 deletions
diff --git a/drivers/Makefile b/drivers/Makefile
index 6ee53c7a57a1..81e36596b1e9 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -106,6 +106,7 @@ obj-$(CONFIG_HID) += hid/
106obj-$(CONFIG_PPC_PS3) += ps3/ 106obj-$(CONFIG_PPC_PS3) += ps3/
107obj-$(CONFIG_OF) += of/ 107obj-$(CONFIG_OF) += of/
108obj-$(CONFIG_SSB) += ssb/ 108obj-$(CONFIG_SSB) += ssb/
109obj-$(CONFIG_VHOST_NET) += vhost/
109obj-$(CONFIG_VIRTIO) += virtio/ 110obj-$(CONFIG_VIRTIO) += virtio/
110obj-$(CONFIG_VLYNQ) += vlynq/ 111obj-$(CONFIG_VLYNQ) += vlynq/
111obj-$(CONFIG_STAGING) += staging/ 112obj-$(CONFIG_STAGING) += staging/
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
new file mode 100644
index 000000000000..9f409f447aea
--- /dev/null
+++ b/drivers/vhost/Kconfig
@@ -0,0 +1,11 @@
1config VHOST_NET
2 tristate "Host kernel accelerator for virtio net (EXPERIMENTAL)"
3 depends on NET && EVENTFD && EXPERIMENTAL
4 ---help---
5 This kernel module can be loaded in host kernel to accelerate
6 guest networking with virtio_net. Not to be confused with virtio_net
7 module itself which needs to be loaded in guest kernel.
8
9 To compile this driver as a module, choose M here: the module will
10 be called vhost_net.
11
diff --git a/drivers/vhost/Makefile b/drivers/vhost/Makefile
new file mode 100644
index 000000000000..72dd02050bb9
--- /dev/null
+++ b/drivers/vhost/Makefile
@@ -0,0 +1,2 @@
1obj-$(CONFIG_VHOST_NET) += vhost_net.o
2vhost_net-y := vhost.o net.o
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
new file mode 100644
index 000000000000..4c8928319e1d
--- /dev/null
+++ b/drivers/vhost/net.c
@@ -0,0 +1,661 @@
1/* Copyright (C) 2009 Red Hat, Inc.
2 * Author: Michael S. Tsirkin <mst@redhat.com>
3 *
4 * This work is licensed under the terms of the GNU GPL, version 2.
5 *
6 * virtio-net server in host kernel.
7 */
8
9#include <linux/compat.h>
10#include <linux/eventfd.h>
11#include <linux/vhost.h>
12#include <linux/virtio_net.h>
13#include <linux/mmu_context.h>
14#include <linux/miscdevice.h>
15#include <linux/module.h>
16#include <linux/mutex.h>
17#include <linux/workqueue.h>
18#include <linux/rcupdate.h>
19#include <linux/file.h>
20
21#include <linux/net.h>
22#include <linux/if_packet.h>
23#include <linux/if_arp.h>
24#include <linux/if_tun.h>
25
26#include <net/sock.h>
27
28#include "vhost.h"
29
30/* Max number of bytes transferred before requeueing the job.
31 * Using this limit prevents one virtqueue from starving others. */
32#define VHOST_NET_WEIGHT 0x80000
33
34enum {
35 VHOST_NET_VQ_RX = 0,
36 VHOST_NET_VQ_TX = 1,
37 VHOST_NET_VQ_MAX = 2,
38};
39
40enum vhost_net_poll_state {
41 VHOST_NET_POLL_DISABLED = 0,
42 VHOST_NET_POLL_STARTED = 1,
43 VHOST_NET_POLL_STOPPED = 2,
44};
45
46struct vhost_net {
47 struct vhost_dev dev;
48 struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX];
49 struct vhost_poll poll[VHOST_NET_VQ_MAX];
50 /* Tells us whether we are polling a socket for TX.
51 * We only do this when socket buffer fills up.
52 * Protected by tx vq lock. */
53 enum vhost_net_poll_state tx_poll_state;
54};
55
56/* Pop first len bytes from iovec. Return number of segments used. */
57static int move_iovec_hdr(struct iovec *from, struct iovec *to,
58 size_t len, int iov_count)
59{
60 int seg = 0;
61 size_t size;
62 while (len && seg < iov_count) {
63 size = min(from->iov_len, len);
64 to->iov_base = from->iov_base;
65 to->iov_len = size;
66 from->iov_len -= size;
67 from->iov_base += size;
68 len -= size;
69 ++from;
70 ++to;
71 ++seg;
72 }
73 return seg;
74}
75
76/* Caller must have TX VQ lock */
77static void tx_poll_stop(struct vhost_net *net)
78{
79 if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED))
80 return;
81 vhost_poll_stop(net->poll + VHOST_NET_VQ_TX);
82 net->tx_poll_state = VHOST_NET_POLL_STOPPED;
83}
84
85/* Caller must have TX VQ lock */
86static void tx_poll_start(struct vhost_net *net, struct socket *sock)
87{
88 if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED))
89 return;
90 vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file);
91 net->tx_poll_state = VHOST_NET_POLL_STARTED;
92}
93
94/* Expects to be always run from workqueue - which acts as
95 * read-size critical section for our kind of RCU. */
96static void handle_tx(struct vhost_net *net)
97{
98 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
99 unsigned head, out, in, s;
100 struct msghdr msg = {
101 .msg_name = NULL,
102 .msg_namelen = 0,
103 .msg_control = NULL,
104 .msg_controllen = 0,
105 .msg_iov = vq->iov,
106 .msg_flags = MSG_DONTWAIT,
107 };
108 size_t len, total_len = 0;
109 int err, wmem;
110 size_t hdr_size;
111 struct socket *sock = rcu_dereference(vq->private_data);
112 if (!sock)
113 return;
114
115 wmem = atomic_read(&sock->sk->sk_wmem_alloc);
116 if (wmem >= sock->sk->sk_sndbuf)
117 return;
118
119 use_mm(net->dev.mm);
120 mutex_lock(&vq->mutex);
121 vhost_disable_notify(vq);
122
123 if (wmem < sock->sk->sk_sndbuf * 2)
124 tx_poll_stop(net);
125 hdr_size = vq->hdr_size;
126
127 for (;;) {
128 head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
129 ARRAY_SIZE(vq->iov),
130 &out, &in,
131 NULL, NULL);
132 /* Nothing new? Wait for eventfd to tell us they refilled. */
133 if (head == vq->num) {
134 wmem = atomic_read(&sock->sk->sk_wmem_alloc);
135 if (wmem >= sock->sk->sk_sndbuf * 3 / 4) {
136 tx_poll_start(net, sock);
137 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
138 break;
139 }
140 if (unlikely(vhost_enable_notify(vq))) {
141 vhost_disable_notify(vq);
142 continue;
143 }
144 break;
145 }
146 if (in) {
147 vq_err(vq, "Unexpected descriptor format for TX: "
148 "out %d, int %d\n", out, in);
149 break;
150 }
151 /* Skip header. TODO: support TSO. */
152 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out);
153 msg.msg_iovlen = out;
154 len = iov_length(vq->iov, out);
155 /* Sanity check */
156 if (!len) {
157 vq_err(vq, "Unexpected header len for TX: "
158 "%zd expected %zd\n",
159 iov_length(vq->hdr, s), hdr_size);
160 break;
161 }
162 /* TODO: Check specific error and bomb out unless ENOBUFS? */
163 err = sock->ops->sendmsg(NULL, sock, &msg, len);
164 if (unlikely(err < 0)) {
165 vhost_discard_vq_desc(vq);
166 tx_poll_start(net, sock);
167 break;
168 }
169 if (err != len)
170 pr_err("Truncated TX packet: "
171 " len %d != %zd\n", err, len);
172 vhost_add_used_and_signal(&net->dev, vq, head, 0);
173 total_len += len;
174 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
175 vhost_poll_queue(&vq->poll);
176 break;
177 }
178 }
179
180 mutex_unlock(&vq->mutex);
181 unuse_mm(net->dev.mm);
182}
183
184/* Expects to be always run from workqueue - which acts as
185 * read-size critical section for our kind of RCU. */
186static void handle_rx(struct vhost_net *net)
187{
188 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
189 unsigned head, out, in, log, s;
190 struct vhost_log *vq_log;
191 struct msghdr msg = {
192 .msg_name = NULL,
193 .msg_namelen = 0,
194 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
195 .msg_controllen = 0,
196 .msg_iov = vq->iov,
197 .msg_flags = MSG_DONTWAIT,
198 };
199
200 struct virtio_net_hdr hdr = {
201 .flags = 0,
202 .gso_type = VIRTIO_NET_HDR_GSO_NONE
203 };
204
205 size_t len, total_len = 0;
206 int err;
207 size_t hdr_size;
208 struct socket *sock = rcu_dereference(vq->private_data);
209 if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue))
210 return;
211
212 use_mm(net->dev.mm);
213 mutex_lock(&vq->mutex);
214 vhost_disable_notify(vq);
215 hdr_size = vq->hdr_size;
216
217 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
218 vq->log : NULL;
219
220 for (;;) {
221 head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
222 ARRAY_SIZE(vq->iov),
223 &out, &in,
224 vq_log, &log);
225 /* OK, now we need to know about added descriptors. */
226 if (head == vq->num) {
227 if (unlikely(vhost_enable_notify(vq))) {
228 /* They have slipped one in as we were
229 * doing that: check again. */
230 vhost_disable_notify(vq);
231 continue;
232 }
233 /* Nothing new? Wait for eventfd to tell us
234 * they refilled. */
235 break;
236 }
237 /* We don't need to be notified again. */
238 if (out) {
239 vq_err(vq, "Unexpected descriptor format for RX: "
240 "out %d, int %d\n",
241 out, in);
242 break;
243 }
244 /* Skip header. TODO: support TSO/mergeable rx buffers. */
245 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, in);
246 msg.msg_iovlen = in;
247 len = iov_length(vq->iov, in);
248 /* Sanity check */
249 if (!len) {
250 vq_err(vq, "Unexpected header len for RX: "
251 "%zd expected %zd\n",
252 iov_length(vq->hdr, s), hdr_size);
253 break;
254 }
255 err = sock->ops->recvmsg(NULL, sock, &msg,
256 len, MSG_DONTWAIT | MSG_TRUNC);
257 /* TODO: Check specific error and bomb out unless EAGAIN? */
258 if (err < 0) {
259 vhost_discard_vq_desc(vq);
260 break;
261 }
262 /* TODO: Should check and handle checksum. */
263 if (err > len) {
264 pr_err("Discarded truncated rx packet: "
265 " len %d > %zd\n", err, len);
266 vhost_discard_vq_desc(vq);
267 continue;
268 }
269 len = err;
270 err = memcpy_toiovec(vq->hdr, (unsigned char *)&hdr, hdr_size);
271 if (err) {
272 vq_err(vq, "Unable to write vnet_hdr at addr %p: %d\n",
273 vq->iov->iov_base, err);
274 break;
275 }
276 len += hdr_size;
277 vhost_add_used_and_signal(&net->dev, vq, head, len);
278 if (unlikely(vq_log))
279 vhost_log_write(vq, vq_log, log, len);
280 total_len += len;
281 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
282 vhost_poll_queue(&vq->poll);
283 break;
284 }
285 }
286
287 mutex_unlock(&vq->mutex);
288 unuse_mm(net->dev.mm);
289}
290
291static void handle_tx_kick(struct work_struct *work)
292{
293 struct vhost_virtqueue *vq;
294 struct vhost_net *net;
295 vq = container_of(work, struct vhost_virtqueue, poll.work);
296 net = container_of(vq->dev, struct vhost_net, dev);
297 handle_tx(net);
298}
299
300static void handle_rx_kick(struct work_struct *work)
301{
302 struct vhost_virtqueue *vq;
303 struct vhost_net *net;
304 vq = container_of(work, struct vhost_virtqueue, poll.work);
305 net = container_of(vq->dev, struct vhost_net, dev);
306 handle_rx(net);
307}
308
309static void handle_tx_net(struct work_struct *work)
310{
311 struct vhost_net *net;
312 net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_TX].work);
313 handle_tx(net);
314}
315
316static void handle_rx_net(struct work_struct *work)
317{
318 struct vhost_net *net;
319 net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_RX].work);
320 handle_rx(net);
321}
322
323static int vhost_net_open(struct inode *inode, struct file *f)
324{
325 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
326 int r;
327 if (!n)
328 return -ENOMEM;
329 n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;
330 n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;
331 r = vhost_dev_init(&n->dev, n->vqs, VHOST_NET_VQ_MAX);
332 if (r < 0) {
333 kfree(n);
334 return r;
335 }
336
337 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT);
338 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN);
339 n->tx_poll_state = VHOST_NET_POLL_DISABLED;
340
341 f->private_data = n;
342
343 return 0;
344}
345
346static void vhost_net_disable_vq(struct vhost_net *n,
347 struct vhost_virtqueue *vq)
348{
349 if (!vq->private_data)
350 return;
351 if (vq == n->vqs + VHOST_NET_VQ_TX) {
352 tx_poll_stop(n);
353 n->tx_poll_state = VHOST_NET_POLL_DISABLED;
354 } else
355 vhost_poll_stop(n->poll + VHOST_NET_VQ_RX);
356}
357
358static void vhost_net_enable_vq(struct vhost_net *n,
359 struct vhost_virtqueue *vq)
360{
361 struct socket *sock = vq->private_data;
362 if (!sock)
363 return;
364 if (vq == n->vqs + VHOST_NET_VQ_TX) {
365 n->tx_poll_state = VHOST_NET_POLL_STOPPED;
366 tx_poll_start(n, sock);
367 } else
368 vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file);
369}
370
371static struct socket *vhost_net_stop_vq(struct vhost_net *n,
372 struct vhost_virtqueue *vq)
373{
374 struct socket *sock;
375
376 mutex_lock(&vq->mutex);
377 sock = vq->private_data;
378 vhost_net_disable_vq(n, vq);
379 rcu_assign_pointer(vq->private_data, NULL);
380 mutex_unlock(&vq->mutex);
381 return sock;
382}
383
384static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
385 struct socket **rx_sock)
386{
387 *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX);
388 *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX);
389}
390
391static void vhost_net_flush_vq(struct vhost_net *n, int index)
392{
393 vhost_poll_flush(n->poll + index);
394 vhost_poll_flush(&n->dev.vqs[index].poll);
395}
396
397static void vhost_net_flush(struct vhost_net *n)
398{
399 vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
400 vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
401}
402
403static int vhost_net_release(struct inode *inode, struct file *f)
404{
405 struct vhost_net *n = f->private_data;
406 struct socket *tx_sock;
407 struct socket *rx_sock;
408
409 vhost_net_stop(n, &tx_sock, &rx_sock);
410 vhost_net_flush(n);
411 vhost_dev_cleanup(&n->dev);
412 if (tx_sock)
413 fput(tx_sock->file);
414 if (rx_sock)
415 fput(rx_sock->file);
416 /* We do an extra flush before freeing memory,
417 * since jobs can re-queue themselves. */
418 vhost_net_flush(n);
419 kfree(n);
420 return 0;
421}
422
423static struct socket *get_raw_socket(int fd)
424{
425 struct {
426 struct sockaddr_ll sa;
427 char buf[MAX_ADDR_LEN];
428 } uaddr;
429 int uaddr_len = sizeof uaddr, r;
430 struct socket *sock = sockfd_lookup(fd, &r);
431 if (!sock)
432 return ERR_PTR(-ENOTSOCK);
433
434 /* Parameter checking */
435 if (sock->sk->sk_type != SOCK_RAW) {
436 r = -ESOCKTNOSUPPORT;
437 goto err;
438 }
439
440 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa,
441 &uaddr_len, 0);
442 if (r)
443 goto err;
444
445 if (uaddr.sa.sll_family != AF_PACKET) {
446 r = -EPFNOSUPPORT;
447 goto err;
448 }
449 return sock;
450err:
451 fput(sock->file);
452 return ERR_PTR(r);
453}
454
455static struct socket *get_tun_socket(int fd)
456{
457 struct file *file = fget(fd);
458 struct socket *sock;
459 if (!file)
460 return ERR_PTR(-EBADF);
461 sock = tun_get_socket(file);
462 if (IS_ERR(sock))
463 fput(file);
464 return sock;
465}
466
467static struct socket *get_socket(int fd)
468{
469 struct socket *sock;
470 /* special case to disable backend */
471 if (fd == -1)
472 return NULL;
473 sock = get_raw_socket(fd);
474 if (!IS_ERR(sock))
475 return sock;
476 sock = get_tun_socket(fd);
477 if (!IS_ERR(sock))
478 return sock;
479 return ERR_PTR(-ENOTSOCK);
480}
481
482static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
483{
484 struct socket *sock, *oldsock;
485 struct vhost_virtqueue *vq;
486 int r;
487
488 mutex_lock(&n->dev.mutex);
489 r = vhost_dev_check_owner(&n->dev);
490 if (r)
491 goto err;
492
493 if (index >= VHOST_NET_VQ_MAX) {
494 r = -ENOBUFS;
495 goto err;
496 }
497 vq = n->vqs + index;
498 mutex_lock(&vq->mutex);
499
500 /* Verify that ring has been setup correctly. */
501 if (!vhost_vq_access_ok(vq)) {
502 r = -EFAULT;
503 goto err;
504 }
505 sock = get_socket(fd);
506 if (IS_ERR(sock)) {
507 r = PTR_ERR(sock);
508 goto err;
509 }
510
511 /* start polling new socket */
512 oldsock = vq->private_data;
513 if (sock == oldsock)
514 goto done;
515
516 vhost_net_disable_vq(n, vq);
517 rcu_assign_pointer(vq->private_data, sock);
518 vhost_net_enable_vq(n, vq);
519 mutex_unlock(&vq->mutex);
520done:
521 if (oldsock) {
522 vhost_net_flush_vq(n, index);
523 fput(oldsock->file);
524 }
525err:
526 mutex_unlock(&n->dev.mutex);
527 return r;
528}
529
530static long vhost_net_reset_owner(struct vhost_net *n)
531{
532 struct socket *tx_sock = NULL;
533 struct socket *rx_sock = NULL;
534 long err;
535 mutex_lock(&n->dev.mutex);
536 err = vhost_dev_check_owner(&n->dev);
537 if (err)
538 goto done;
539 vhost_net_stop(n, &tx_sock, &rx_sock);
540 vhost_net_flush(n);
541 err = vhost_dev_reset_owner(&n->dev);
542done:
543 mutex_unlock(&n->dev.mutex);
544 if (tx_sock)
545 fput(tx_sock->file);
546 if (rx_sock)
547 fput(rx_sock->file);
548 return err;
549}
550
551static int vhost_net_set_features(struct vhost_net *n, u64 features)
552{
553 size_t hdr_size = features & (1 << VHOST_NET_F_VIRTIO_NET_HDR) ?
554 sizeof(struct virtio_net_hdr) : 0;
555 int i;
556 mutex_lock(&n->dev.mutex);
557 if ((features & (1 << VHOST_F_LOG_ALL)) &&
558 !vhost_log_access_ok(&n->dev)) {
559 mutex_unlock(&n->dev.mutex);
560 return -EFAULT;
561 }
562 n->dev.acked_features = features;
563 smp_wmb();
564 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
565 mutex_lock(&n->vqs[i].mutex);
566 n->vqs[i].hdr_size = hdr_size;
567 mutex_unlock(&n->vqs[i].mutex);
568 }
569 vhost_net_flush(n);
570 mutex_unlock(&n->dev.mutex);
571 return 0;
572}
573
574static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
575 unsigned long arg)
576{
577 struct vhost_net *n = f->private_data;
578 void __user *argp = (void __user *)arg;
579 u64 __user *featurep = argp;
580 struct vhost_vring_file backend;
581 u64 features;
582 int r;
583 switch (ioctl) {
584 case VHOST_NET_SET_BACKEND:
585 r = copy_from_user(&backend, argp, sizeof backend);
586 if (r < 0)
587 return r;
588 return vhost_net_set_backend(n, backend.index, backend.fd);
589 case VHOST_GET_FEATURES:
590 features = VHOST_FEATURES;
591 return copy_to_user(featurep, &features, sizeof features);
592 case VHOST_SET_FEATURES:
593 r = copy_from_user(&features, featurep, sizeof features);
594 if (r < 0)
595 return r;
596 if (features & ~VHOST_FEATURES)
597 return -EOPNOTSUPP;
598 return vhost_net_set_features(n, features);
599 case VHOST_RESET_OWNER:
600 return vhost_net_reset_owner(n);
601 default:
602 mutex_lock(&n->dev.mutex);
603 r = vhost_dev_ioctl(&n->dev, ioctl, arg);
604 vhost_net_flush(n);
605 mutex_unlock(&n->dev.mutex);
606 return r;
607 }
608}
609
610#ifdef CONFIG_COMPAT
611static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl,
612 unsigned long arg)
613{
614 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
615}
616#endif
617
618const static struct file_operations vhost_net_fops = {
619 .owner = THIS_MODULE,
620 .release = vhost_net_release,
621 .unlocked_ioctl = vhost_net_ioctl,
622#ifdef CONFIG_COMPAT
623 .compat_ioctl = vhost_net_compat_ioctl,
624#endif
625 .open = vhost_net_open,
626};
627
628static struct miscdevice vhost_net_misc = {
629 VHOST_NET_MINOR,
630 "vhost-net",
631 &vhost_net_fops,
632};
633
634int vhost_net_init(void)
635{
636 int r = vhost_init();
637 if (r)
638 goto err_init;
639 r = misc_register(&vhost_net_misc);
640 if (r)
641 goto err_reg;
642 return 0;
643err_reg:
644 vhost_cleanup();
645err_init:
646 return r;
647
648}
649module_init(vhost_net_init);
650
651void vhost_net_exit(void)
652{
653 misc_deregister(&vhost_net_misc);
654 vhost_cleanup();
655}
656module_exit(vhost_net_exit);
657
658MODULE_VERSION("0.0.1");
659MODULE_LICENSE("GPL v2");
660MODULE_AUTHOR("Michael S. Tsirkin");
661MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
new file mode 100644
index 000000000000..c8c25dbc5857
--- /dev/null
+++ b/drivers/vhost/vhost.c
@@ -0,0 +1,1098 @@
1/* 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
7 * Documentation/lguest/lguest.c, by Rusty Russell
8 *
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>
18#include <linux/miscdevice.h>
19#include <linux/mutex.h>
20#include <linux/workqueue.h>
21#include <linux/rcupdate.h>
22#include <linux/poll.h>
23#include <linux/file.h>
24#include <linux/highmem.h>
25
26#include <linux/net.h>
27#include <linux/if_packet.h>
28#include <linux/if_arp.h>
29
30#include <net/sock.h>
31
32#include "vhost.h"
33
34enum {
35 VHOST_MEMORY_MAX_NREGIONS = 64,
36 VHOST_MEMORY_F_LOG = 0x1,
37};
38
39static struct workqueue_struct *vhost_workqueue;
40
41static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
42 poll_table *pt)
43{
44 struct vhost_poll *poll;
45 poll = container_of(pt, struct vhost_poll, table);
46
47 poll->wqh = wqh;
48 add_wait_queue(wqh, &poll->wait);
49}
50
51static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,
52 void *key)
53{
54 struct vhost_poll *poll;
55 poll = container_of(wait, struct vhost_poll, wait);
56 if (!((unsigned long)key & poll->mask))
57 return 0;
58
59 queue_work(vhost_workqueue, &poll->work);
60 return 0;
61}
62
63/* Init poll structure */
64void vhost_poll_init(struct vhost_poll *poll, work_func_t func,
65 unsigned long mask)
66{
67 INIT_WORK(&poll->work, func);
68 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
69 init_poll_funcptr(&poll->table, vhost_poll_func);
70 poll->mask = mask;
71}
72
73/* Start polling a file. We add ourselves to file's wait queue. The caller must
74 * keep a reference to a file until after vhost_poll_stop is called. */
75void vhost_poll_start(struct vhost_poll *poll, struct file *file)
76{
77 unsigned long mask;
78 mask = file->f_op->poll(file, &poll->table);
79 if (mask)
80 vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
81}
82
83/* Stop polling a file. After this function returns, it becomes safe to drop the
84 * file reference. You must also flush afterwards. */
85void vhost_poll_stop(struct vhost_poll *poll)
86{
87 remove_wait_queue(poll->wqh, &poll->wait);
88}
89
90/* Flush any work that has been scheduled. When calling this, don't hold any
91 * locks that are also used by the callback. */
92void vhost_poll_flush(struct vhost_poll *poll)
93{
94 flush_work(&poll->work);
95}
96
97void vhost_poll_queue(struct vhost_poll *poll)
98{
99 queue_work(vhost_workqueue, &poll->work);
100}
101
102static void vhost_vq_reset(struct vhost_dev *dev,
103 struct vhost_virtqueue *vq)
104{
105 vq->num = 1;
106 vq->desc = NULL;
107 vq->avail = NULL;
108 vq->used = NULL;
109 vq->last_avail_idx = 0;
110 vq->avail_idx = 0;
111 vq->last_used_idx = 0;
112 vq->used_flags = 0;
113 vq->used_flags = 0;
114 vq->log_used = false;
115 vq->log_addr = -1ull;
116 vq->hdr_size = 0;
117 vq->private_data = NULL;
118 vq->log_base = NULL;
119 vq->error_ctx = NULL;
120 vq->error = NULL;
121 vq->kick = NULL;
122 vq->call_ctx = NULL;
123 vq->call = NULL;
124}
125
126long vhost_dev_init(struct vhost_dev *dev,
127 struct vhost_virtqueue *vqs, int nvqs)
128{
129 int i;
130 dev->vqs = vqs;
131 dev->nvqs = nvqs;
132 mutex_init(&dev->mutex);
133 dev->log_ctx = NULL;
134 dev->log_file = NULL;
135 dev->memory = NULL;
136 dev->mm = NULL;
137
138 for (i = 0; i < dev->nvqs; ++i) {
139 dev->vqs[i].dev = dev;
140 mutex_init(&dev->vqs[i].mutex);
141 vhost_vq_reset(dev, dev->vqs + i);
142 if (dev->vqs[i].handle_kick)
143 vhost_poll_init(&dev->vqs[i].poll,
144 dev->vqs[i].handle_kick,
145 POLLIN);
146 }
147 return 0;
148}
149
150/* Caller should have device mutex */
151long vhost_dev_check_owner(struct vhost_dev *dev)
152{
153 /* Are you the owner? If not, I don't think you mean to do that */
154 return dev->mm == current->mm ? 0 : -EPERM;
155}
156
157/* Caller should have device mutex */
158static long vhost_dev_set_owner(struct vhost_dev *dev)
159{
160 /* Is there an owner already? */
161 if (dev->mm)
162 return -EBUSY;
163 /* No owner, become one */
164 dev->mm = get_task_mm(current);
165 return 0;
166}
167
168/* Caller should have device mutex */
169long vhost_dev_reset_owner(struct vhost_dev *dev)
170{
171 struct vhost_memory *memory;
172
173 /* Restore memory to default empty mapping. */
174 memory = kmalloc(offsetof(struct vhost_memory, regions), GFP_KERNEL);
175 if (!memory)
176 return -ENOMEM;
177
178 vhost_dev_cleanup(dev);
179
180 memory->nregions = 0;
181 dev->memory = memory;
182 return 0;
183}
184
185/* Caller should have device mutex */
186void vhost_dev_cleanup(struct vhost_dev *dev)
187{
188 int i;
189 for (i = 0; i < dev->nvqs; ++i) {
190 if (dev->vqs[i].kick && dev->vqs[i].handle_kick) {
191 vhost_poll_stop(&dev->vqs[i].poll);
192 vhost_poll_flush(&dev->vqs[i].poll);
193 }
194 if (dev->vqs[i].error_ctx)
195 eventfd_ctx_put(dev->vqs[i].error_ctx);
196 if (dev->vqs[i].error)
197 fput(dev->vqs[i].error);
198 if (dev->vqs[i].kick)
199 fput(dev->vqs[i].kick);
200 if (dev->vqs[i].call_ctx)
201 eventfd_ctx_put(dev->vqs[i].call_ctx);
202 if (dev->vqs[i].call)
203 fput(dev->vqs[i].call);
204 vhost_vq_reset(dev, dev->vqs + i);
205 }
206 if (dev->log_ctx)
207 eventfd_ctx_put(dev->log_ctx);
208 dev->log_ctx = NULL;
209 if (dev->log_file)
210 fput(dev->log_file);
211 dev->log_file = NULL;
212 /* No one will access memory at this point */
213 kfree(dev->memory);
214 dev->memory = NULL;
215 if (dev->mm)
216 mmput(dev->mm);
217 dev->mm = NULL;
218}
219
220static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
221{
222 u64 a = addr / VHOST_PAGE_SIZE / 8;
223 /* Make sure 64 bit math will not overflow. */
224 if (a > ULONG_MAX - (unsigned long)log_base ||
225 a + (unsigned long)log_base > ULONG_MAX)
226 return -EFAULT;
227
228 return access_ok(VERIFY_WRITE, log_base + a,
229 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
230}
231
232/* Caller should have vq mutex and device mutex. */
233static int vq_memory_access_ok(void __user *log_base, struct vhost_memory *mem,
234 int log_all)
235{
236 int i;
237 for (i = 0; i < mem->nregions; ++i) {
238 struct vhost_memory_region *m = mem->regions + i;
239 unsigned long a = m->userspace_addr;
240 if (m->memory_size > ULONG_MAX)
241 return 0;
242 else if (!access_ok(VERIFY_WRITE, (void __user *)a,
243 m->memory_size))
244 return 0;
245 else if (log_all && !log_access_ok(log_base,
246 m->guest_phys_addr,
247 m->memory_size))
248 return 0;
249 }
250 return 1;
251}
252
253/* Can we switch to this memory table? */
254/* Caller should have device mutex but not vq mutex */
255static int memory_access_ok(struct vhost_dev *d, struct vhost_memory *mem,
256 int log_all)
257{
258 int i;
259 for (i = 0; i < d->nvqs; ++i) {
260 int ok;
261 mutex_lock(&d->vqs[i].mutex);
262 /* If ring is inactive, will check when it's enabled. */
263 if (d->vqs[i].private_data)
264 ok = vq_memory_access_ok(d->vqs[i].log_base, mem,
265 log_all);
266 else
267 ok = 1;
268 mutex_unlock(&d->vqs[i].mutex);
269 if (!ok)
270 return 0;
271 }
272 return 1;
273}
274
275static int vq_access_ok(unsigned int num,
276 struct vring_desc __user *desc,
277 struct vring_avail __user *avail,
278 struct vring_used __user *used)
279{
280 return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
281 access_ok(VERIFY_READ, avail,
282 sizeof *avail + num * sizeof *avail->ring) &&
283 access_ok(VERIFY_WRITE, used,
284 sizeof *used + num * sizeof *used->ring);
285}
286
287/* Can we log writes? */
288/* Caller should have device mutex but not vq mutex */
289int vhost_log_access_ok(struct vhost_dev *dev)
290{
291 return memory_access_ok(dev, dev->memory, 1);
292}
293
294/* Verify access for write logging. */
295/* Caller should have vq mutex and device mutex */
296static int vq_log_access_ok(struct vhost_virtqueue *vq, void __user *log_base)
297{
298 return vq_memory_access_ok(log_base, vq->dev->memory,
299 vhost_has_feature(vq->dev, VHOST_F_LOG_ALL)) &&
300 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
301 sizeof *vq->used +
302 vq->num * sizeof *vq->used->ring));
303}
304
305/* Can we start vq? */
306/* Caller should have vq mutex and device mutex */
307int vhost_vq_access_ok(struct vhost_virtqueue *vq)
308{
309 return vq_access_ok(vq->num, vq->desc, vq->avail, vq->used) &&
310 vq_log_access_ok(vq, vq->log_base);
311}
312
313static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
314{
315 struct vhost_memory mem, *newmem, *oldmem;
316 unsigned long size = offsetof(struct vhost_memory, regions);
317 long r;
318 r = copy_from_user(&mem, m, size);
319 if (r)
320 return r;
321 if (mem.padding)
322 return -EOPNOTSUPP;
323 if (mem.nregions > VHOST_MEMORY_MAX_NREGIONS)
324 return -E2BIG;
325 newmem = kmalloc(size + mem.nregions * sizeof *m->regions, GFP_KERNEL);
326 if (!newmem)
327 return -ENOMEM;
328
329 memcpy(newmem, &mem, size);
330 r = copy_from_user(newmem->regions, m->regions,
331 mem.nregions * sizeof *m->regions);
332 if (r) {
333 kfree(newmem);
334 return r;
335 }
336
337 if (!memory_access_ok(d, newmem, vhost_has_feature(d, VHOST_F_LOG_ALL)))
338 return -EFAULT;
339 oldmem = d->memory;
340 rcu_assign_pointer(d->memory, newmem);
341 synchronize_rcu();
342 kfree(oldmem);
343 return 0;
344}
345
346static int init_used(struct vhost_virtqueue *vq,
347 struct vring_used __user *used)
348{
349 int r = put_user(vq->used_flags, &used->flags);
350 if (r)
351 return r;
352 return get_user(vq->last_used_idx, &used->idx);
353}
354
355static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp)
356{
357 struct file *eventfp, *filep = NULL,
358 *pollstart = NULL, *pollstop = NULL;
359 struct eventfd_ctx *ctx = NULL;
360 u32 __user *idxp = argp;
361 struct vhost_virtqueue *vq;
362 struct vhost_vring_state s;
363 struct vhost_vring_file f;
364 struct vhost_vring_addr a;
365 u32 idx;
366 long r;
367
368 r = get_user(idx, idxp);
369 if (r < 0)
370 return r;
371 if (idx > d->nvqs)
372 return -ENOBUFS;
373
374 vq = d->vqs + idx;
375
376 mutex_lock(&vq->mutex);
377
378 switch (ioctl) {
379 case VHOST_SET_VRING_NUM:
380 /* Resizing ring with an active backend?
381 * You don't want to do that. */
382 if (vq->private_data) {
383 r = -EBUSY;
384 break;
385 }
386 r = copy_from_user(&s, argp, sizeof s);
387 if (r < 0)
388 break;
389 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
390 r = -EINVAL;
391 break;
392 }
393 vq->num = s.num;
394 break;
395 case VHOST_SET_VRING_BASE:
396 /* Moving base with an active backend?
397 * You don't want to do that. */
398 if (vq->private_data) {
399 r = -EBUSY;
400 break;
401 }
402 r = copy_from_user(&s, argp, sizeof s);
403 if (r < 0)
404 break;
405 if (s.num > 0xffff) {
406 r = -EINVAL;
407 break;
408 }
409 vq->last_avail_idx = s.num;
410 /* Forget the cached index value. */
411 vq->avail_idx = vq->last_avail_idx;
412 break;
413 case VHOST_GET_VRING_BASE:
414 s.index = idx;
415 s.num = vq->last_avail_idx;
416 r = copy_to_user(argp, &s, sizeof s);
417 break;
418 case VHOST_SET_VRING_ADDR:
419 r = copy_from_user(&a, argp, sizeof a);
420 if (r < 0)
421 break;
422 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
423 r = -EOPNOTSUPP;
424 break;
425 }
426 /* For 32bit, verify that the top 32bits of the user
427 data are set to zero. */
428 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
429 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
430 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
431 r = -EFAULT;
432 break;
433 }
434 if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) ||
435 (a.used_user_addr & (sizeof *vq->used->ring - 1)) ||
436 (a.log_guest_addr & (sizeof *vq->used->ring - 1))) {
437 r = -EINVAL;
438 break;
439 }
440
441 /* We only verify access here if backend is configured.
442 * If it is not, we don't as size might not have been setup.
443 * We will verify when backend is configured. */
444 if (vq->private_data) {
445 if (!vq_access_ok(vq->num,
446 (void __user *)(unsigned long)a.desc_user_addr,
447 (void __user *)(unsigned long)a.avail_user_addr,
448 (void __user *)(unsigned long)a.used_user_addr)) {
449 r = -EINVAL;
450 break;
451 }
452
453 /* Also validate log access for used ring if enabled. */
454 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
455 !log_access_ok(vq->log_base, a.log_guest_addr,
456 sizeof *vq->used +
457 vq->num * sizeof *vq->used->ring)) {
458 r = -EINVAL;
459 break;
460 }
461 }
462
463 r = init_used(vq, (struct vring_used __user *)(unsigned long)
464 a.used_user_addr);
465 if (r)
466 break;
467 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
468 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
469 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
470 vq->log_addr = a.log_guest_addr;
471 vq->used = (void __user *)(unsigned long)a.used_user_addr;
472 break;
473 case VHOST_SET_VRING_KICK:
474 r = copy_from_user(&f, argp, sizeof f);
475 if (r < 0)
476 break;
477 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
478 if (IS_ERR(eventfp))
479 return PTR_ERR(eventfp);
480 if (eventfp != vq->kick) {
481 pollstop = filep = vq->kick;
482 pollstart = vq->kick = eventfp;
483 } else
484 filep = eventfp;
485 break;
486 case VHOST_SET_VRING_CALL:
487 r = copy_from_user(&f, argp, sizeof f);
488 if (r < 0)
489 break;
490 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
491 if (IS_ERR(eventfp))
492 return PTR_ERR(eventfp);
493 if (eventfp != vq->call) {
494 filep = vq->call;
495 ctx = vq->call_ctx;
496 vq->call = eventfp;
497 vq->call_ctx = eventfp ?
498 eventfd_ctx_fileget(eventfp) : NULL;
499 } else
500 filep = eventfp;
501 break;
502 case VHOST_SET_VRING_ERR:
503 r = copy_from_user(&f, argp, sizeof f);
504 if (r < 0)
505 break;
506 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
507 if (IS_ERR(eventfp))
508 return PTR_ERR(eventfp);
509 if (eventfp != vq->error) {
510 filep = vq->error;
511 vq->error = eventfp;
512 ctx = vq->error_ctx;
513 vq->error_ctx = eventfp ?
514 eventfd_ctx_fileget(eventfp) : NULL;
515 } else
516 filep = eventfp;
517 break;
518 default:
519 r = -ENOIOCTLCMD;
520 }
521
522 if (pollstop && vq->handle_kick)
523 vhost_poll_stop(&vq->poll);
524
525 if (ctx)
526 eventfd_ctx_put(ctx);
527 if (filep)
528 fput(filep);
529
530 if (pollstart && vq->handle_kick)
531 vhost_poll_start(&vq->poll, vq->kick);
532
533 mutex_unlock(&vq->mutex);
534
535 if (pollstop && vq->handle_kick)
536 vhost_poll_flush(&vq->poll);
537 return r;
538}
539
540/* Caller must have device mutex */
541long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, unsigned long arg)
542{
543 void __user *argp = (void __user *)arg;
544 struct file *eventfp, *filep = NULL;
545 struct eventfd_ctx *ctx = NULL;
546 u64 p;
547 long r;
548 int i, fd;
549
550 /* If you are not the owner, you can become one */
551 if (ioctl == VHOST_SET_OWNER) {
552 r = vhost_dev_set_owner(d);
553 goto done;
554 }
555
556 /* You must be the owner to do anything else */
557 r = vhost_dev_check_owner(d);
558 if (r)
559 goto done;
560
561 switch (ioctl) {
562 case VHOST_SET_MEM_TABLE:
563 r = vhost_set_memory(d, argp);
564 break;
565 case VHOST_SET_LOG_BASE:
566 r = copy_from_user(&p, argp, sizeof p);
567 if (r < 0)
568 break;
569 if ((u64)(unsigned long)p != p) {
570 r = -EFAULT;
571 break;
572 }
573 for (i = 0; i < d->nvqs; ++i) {
574 struct vhost_virtqueue *vq;
575 void __user *base = (void __user *)(unsigned long)p;
576 vq = d->vqs + i;
577 mutex_lock(&vq->mutex);
578 /* If ring is inactive, will check when it's enabled. */
579 if (vq->private_data && !vq_log_access_ok(vq, base))
580 r = -EFAULT;
581 else
582 vq->log_base = base;
583 mutex_unlock(&vq->mutex);
584 }
585 break;
586 case VHOST_SET_LOG_FD:
587 r = get_user(fd, (int __user *)argp);
588 if (r < 0)
589 break;
590 eventfp = fd == -1 ? NULL : eventfd_fget(fd);
591 if (IS_ERR(eventfp)) {
592 r = PTR_ERR(eventfp);
593 break;
594 }
595 if (eventfp != d->log_file) {
596 filep = d->log_file;
597 ctx = d->log_ctx;
598 d->log_ctx = eventfp ?
599 eventfd_ctx_fileget(eventfp) : NULL;
600 } else
601 filep = eventfp;
602 for (i = 0; i < d->nvqs; ++i) {
603 mutex_lock(&d->vqs[i].mutex);
604 d->vqs[i].log_ctx = d->log_ctx;
605 mutex_unlock(&d->vqs[i].mutex);
606 }
607 if (ctx)
608 eventfd_ctx_put(ctx);
609 if (filep)
610 fput(filep);
611 break;
612 default:
613 r = vhost_set_vring(d, ioctl, argp);
614 break;
615 }
616done:
617 return r;
618}
619
620static const struct vhost_memory_region *find_region(struct vhost_memory *mem,
621 __u64 addr, __u32 len)
622{
623 struct vhost_memory_region *reg;
624 int i;
625 /* linear search is not brilliant, but we really have on the order of 6
626 * regions in practice */
627 for (i = 0; i < mem->nregions; ++i) {
628 reg = mem->regions + i;
629 if (reg->guest_phys_addr <= addr &&
630 reg->guest_phys_addr + reg->memory_size - 1 >= addr)
631 return reg;
632 }
633 return NULL;
634}
635
636/* TODO: This is really inefficient. We need something like get_user()
637 * (instruction directly accesses the data, with an exception table entry
638 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
639 */
640static int set_bit_to_user(int nr, void __user *addr)
641{
642 unsigned long log = (unsigned long)addr;
643 struct page *page;
644 void *base;
645 int bit = nr + (log % PAGE_SIZE) * 8;
646 int r;
647 r = get_user_pages_fast(log, 1, 1, &page);
648 if (r)
649 return r;
650 base = kmap_atomic(page, KM_USER0);
651 set_bit(bit, base);
652 kunmap_atomic(base, KM_USER0);
653 set_page_dirty_lock(page);
654 put_page(page);
655 return 0;
656}
657
658static int log_write(void __user *log_base,
659 u64 write_address, u64 write_length)
660{
661 int r;
662 if (!write_length)
663 return 0;
664 write_address /= VHOST_PAGE_SIZE;
665 for (;;) {
666 u64 base = (u64)(unsigned long)log_base;
667 u64 log = base + write_address / 8;
668 int bit = write_address % 8;
669 if ((u64)(unsigned long)log != log)
670 return -EFAULT;
671 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
672 if (r < 0)
673 return r;
674 if (write_length <= VHOST_PAGE_SIZE)
675 break;
676 write_length -= VHOST_PAGE_SIZE;
677 write_address += VHOST_PAGE_SIZE;
678 }
679 return r;
680}
681
682int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
683 unsigned int log_num, u64 len)
684{
685 int i, r;
686
687 /* Make sure data written is seen before log. */
688 wmb();
689 for (i = 0; i < log_num; ++i) {
690 u64 l = min(log[i].len, len);
691 r = log_write(vq->log_base, log[i].addr, l);
692 if (r < 0)
693 return r;
694 len -= l;
695 if (!len)
696 return 0;
697 }
698 if (vq->log_ctx)
699 eventfd_signal(vq->log_ctx, 1);
700 /* Length written exceeds what we have stored. This is a bug. */
701 BUG();
702 return 0;
703}
704
705int translate_desc(struct vhost_dev *dev, u64 addr, u32 len,
706 struct iovec iov[], int iov_size)
707{
708 const struct vhost_memory_region *reg;
709 struct vhost_memory *mem;
710 struct iovec *_iov;
711 u64 s = 0;
712 int ret = 0;
713
714 rcu_read_lock();
715
716 mem = rcu_dereference(dev->memory);
717 while ((u64)len > s) {
718 u64 size;
719 if (ret >= iov_size) {
720 ret = -ENOBUFS;
721 break;
722 }
723 reg = find_region(mem, addr, len);
724 if (!reg) {
725 ret = -EFAULT;
726 break;
727 }
728 _iov = iov + ret;
729 size = reg->memory_size - addr + reg->guest_phys_addr;
730 _iov->iov_len = min((u64)len, size);
731 _iov->iov_base = (void *)(unsigned long)
732 (reg->userspace_addr + addr - reg->guest_phys_addr);
733 s += size;
734 addr += size;
735 ++ret;
736 }
737
738 rcu_read_unlock();
739 return ret;
740}
741
742/* Each buffer in the virtqueues is actually a chain of descriptors. This
743 * function returns the next descriptor in the chain,
744 * or -1U if we're at the end. */
745static unsigned next_desc(struct vring_desc *desc)
746{
747 unsigned int next;
748
749 /* If this descriptor says it doesn't chain, we're done. */
750 if (!(desc->flags & VRING_DESC_F_NEXT))
751 return -1U;
752
753 /* Check they're not leading us off end of descriptors. */
754 next = desc->next;
755 /* Make sure compiler knows to grab that: we don't want it changing! */
756 /* We will use the result as an index in an array, so most
757 * architectures only need a compiler barrier here. */
758 read_barrier_depends();
759
760 return next;
761}
762
763static unsigned get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq,
764 struct iovec iov[], unsigned int iov_size,
765 unsigned int *out_num, unsigned int *in_num,
766 struct vhost_log *log, unsigned int *log_num,
767 struct vring_desc *indirect)
768{
769 struct vring_desc desc;
770 unsigned int i = 0, count, found = 0;
771 int ret;
772
773 /* Sanity check */
774 if (indirect->len % sizeof desc) {
775 vq_err(vq, "Invalid length in indirect descriptor: "
776 "len 0x%llx not multiple of 0x%zx\n",
777 (unsigned long long)indirect->len,
778 sizeof desc);
779 return -EINVAL;
780 }
781
782 ret = translate_desc(dev, indirect->addr, indirect->len, vq->indirect,
783 ARRAY_SIZE(vq->indirect));
784 if (ret < 0) {
785 vq_err(vq, "Translation failure %d in indirect.\n", ret);
786 return ret;
787 }
788
789 /* We will use the result as an address to read from, so most
790 * architectures only need a compiler barrier here. */
791 read_barrier_depends();
792
793 count = indirect->len / sizeof desc;
794 /* Buffers are chained via a 16 bit next field, so
795 * we can have at most 2^16 of these. */
796 if (count > USHORT_MAX + 1) {
797 vq_err(vq, "Indirect buffer length too big: %d\n",
798 indirect->len);
799 return -E2BIG;
800 }
801
802 do {
803 unsigned iov_count = *in_num + *out_num;
804 if (++found > count) {
805 vq_err(vq, "Loop detected: last one at %u "
806 "indirect size %u\n",
807 i, count);
808 return -EINVAL;
809 }
810 if (memcpy_fromiovec((unsigned char *)&desc, vq->indirect,
811 sizeof desc)) {
812 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
813 i, (size_t)indirect->addr + i * sizeof desc);
814 return -EINVAL;
815 }
816 if (desc.flags & VRING_DESC_F_INDIRECT) {
817 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
818 i, (size_t)indirect->addr + i * sizeof desc);
819 return -EINVAL;
820 }
821
822 ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count,
823 iov_size - iov_count);
824 if (ret < 0) {
825 vq_err(vq, "Translation failure %d indirect idx %d\n",
826 ret, i);
827 return ret;
828 }
829 /* If this is an input descriptor, increment that count. */
830 if (desc.flags & VRING_DESC_F_WRITE) {
831 *in_num += ret;
832 if (unlikely(log)) {
833 log[*log_num].addr = desc.addr;
834 log[*log_num].len = desc.len;
835 ++*log_num;
836 }
837 } else {
838 /* If it's an output descriptor, they're all supposed
839 * to come before any input descriptors. */
840 if (*in_num) {
841 vq_err(vq, "Indirect descriptor "
842 "has out after in: idx %d\n", i);
843 return -EINVAL;
844 }
845 *out_num += ret;
846 }
847 } while ((i = next_desc(&desc)) != -1);
848 return 0;
849}
850
851/* This looks in the virtqueue and for the first available buffer, and converts
852 * it to an iovec for convenient access. Since descriptors consist of some
853 * number of output then some number of input descriptors, it's actually two
854 * iovecs, but we pack them into one and note how many of each there were.
855 *
856 * This function returns the descriptor number found, or vq->num (which
857 * is never a valid descriptor number) if none was found. */
858unsigned vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
859 struct iovec iov[], unsigned int iov_size,
860 unsigned int *out_num, unsigned int *in_num,
861 struct vhost_log *log, unsigned int *log_num)
862{
863 struct vring_desc desc;
864 unsigned int i, head, found = 0;
865 u16 last_avail_idx;
866 int ret;
867
868 /* Check it isn't doing very strange things with descriptor numbers. */
869 last_avail_idx = vq->last_avail_idx;
870 if (get_user(vq->avail_idx, &vq->avail->idx)) {
871 vq_err(vq, "Failed to access avail idx at %p\n",
872 &vq->avail->idx);
873 return vq->num;
874 }
875
876 if ((u16)(vq->avail_idx - last_avail_idx) > vq->num) {
877 vq_err(vq, "Guest moved used index from %u to %u",
878 last_avail_idx, vq->avail_idx);
879 return vq->num;
880 }
881
882 /* If there's nothing new since last we looked, return invalid. */
883 if (vq->avail_idx == last_avail_idx)
884 return vq->num;
885
886 /* Only get avail ring entries after they have been exposed by guest. */
887 rmb();
888
889 /* Grab the next descriptor number they're advertising, and increment
890 * the index we've seen. */
891 if (get_user(head, &vq->avail->ring[last_avail_idx % vq->num])) {
892 vq_err(vq, "Failed to read head: idx %d address %p\n",
893 last_avail_idx,
894 &vq->avail->ring[last_avail_idx % vq->num]);
895 return vq->num;
896 }
897
898 /* If their number is silly, that's an error. */
899 if (head >= vq->num) {
900 vq_err(vq, "Guest says index %u > %u is available",
901 head, vq->num);
902 return vq->num;
903 }
904
905 /* When we start there are none of either input nor output. */
906 *out_num = *in_num = 0;
907 if (unlikely(log))
908 *log_num = 0;
909
910 i = head;
911 do {
912 unsigned iov_count = *in_num + *out_num;
913 if (i >= vq->num) {
914 vq_err(vq, "Desc index is %u > %u, head = %u",
915 i, vq->num, head);
916 return vq->num;
917 }
918 if (++found > vq->num) {
919 vq_err(vq, "Loop detected: last one at %u "
920 "vq size %u head %u\n",
921 i, vq->num, head);
922 return vq->num;
923 }
924 ret = copy_from_user(&desc, vq->desc + i, sizeof desc);
925 if (ret) {
926 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
927 i, vq->desc + i);
928 return vq->num;
929 }
930 if (desc.flags & VRING_DESC_F_INDIRECT) {
931 ret = get_indirect(dev, vq, iov, iov_size,
932 out_num, in_num,
933 log, log_num, &desc);
934 if (ret < 0) {
935 vq_err(vq, "Failure detected "
936 "in indirect descriptor at idx %d\n", i);
937 return vq->num;
938 }
939 continue;
940 }
941
942 ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count,
943 iov_size - iov_count);
944 if (ret < 0) {
945 vq_err(vq, "Translation failure %d descriptor idx %d\n",
946 ret, i);
947 return vq->num;
948 }
949 if (desc.flags & VRING_DESC_F_WRITE) {
950 /* If this is an input descriptor,
951 * increment that count. */
952 *in_num += ret;
953 if (unlikely(log)) {
954 log[*log_num].addr = desc.addr;
955 log[*log_num].len = desc.len;
956 ++*log_num;
957 }
958 } else {
959 /* If it's an output descriptor, they're all supposed
960 * to come before any input descriptors. */
961 if (*in_num) {
962 vq_err(vq, "Descriptor has out after in: "
963 "idx %d\n", i);
964 return vq->num;
965 }
966 *out_num += ret;
967 }
968 } while ((i = next_desc(&desc)) != -1);
969
970 /* On success, increment avail index. */
971 vq->last_avail_idx++;
972 return head;
973}
974
975/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
976void vhost_discard_vq_desc(struct vhost_virtqueue *vq)
977{
978 vq->last_avail_idx--;
979}
980
981/* After we've used one of their buffers, we tell them about it. We'll then
982 * want to notify the guest, using eventfd. */
983int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
984{
985 struct vring_used_elem *used;
986
987 /* The virtqueue contains a ring of used buffers. Get a pointer to the
988 * next entry in that used ring. */
989 used = &vq->used->ring[vq->last_used_idx % vq->num];
990 if (put_user(head, &used->id)) {
991 vq_err(vq, "Failed to write used id");
992 return -EFAULT;
993 }
994 if (put_user(len, &used->len)) {
995 vq_err(vq, "Failed to write used len");
996 return -EFAULT;
997 }
998 /* Make sure buffer is written before we update index. */
999 wmb();
1000 if (put_user(vq->last_used_idx + 1, &vq->used->idx)) {
1001 vq_err(vq, "Failed to increment used idx");
1002 return -EFAULT;
1003 }
1004 if (unlikely(vq->log_used)) {
1005 /* Make sure data is seen before log. */
1006 wmb();
1007 log_write(vq->log_base, vq->log_addr + sizeof *vq->used->ring *
1008 (vq->last_used_idx % vq->num),
1009 sizeof *vq->used->ring);
1010 log_write(vq->log_base, vq->log_addr, sizeof *vq->used->ring);
1011 if (vq->log_ctx)
1012 eventfd_signal(vq->log_ctx, 1);
1013 }
1014 vq->last_used_idx++;
1015 return 0;
1016}
1017
1018/* This actually signals the guest, using eventfd. */
1019void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
1020{
1021 __u16 flags = 0;
1022 if (get_user(flags, &vq->avail->flags)) {
1023 vq_err(vq, "Failed to get flags");
1024 return;
1025 }
1026
1027 /* If they don't want an interrupt, don't signal, unless empty. */
1028 if ((flags & VRING_AVAIL_F_NO_INTERRUPT) &&
1029 (vq->avail_idx != vq->last_avail_idx ||
1030 !vhost_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY)))
1031 return;
1032
1033 /* Signal the Guest tell them we used something up. */
1034 if (vq->call_ctx)
1035 eventfd_signal(vq->call_ctx, 1);
1036}
1037
1038/* And here's the combo meal deal. Supersize me! */
1039void vhost_add_used_and_signal(struct vhost_dev *dev,
1040 struct vhost_virtqueue *vq,
1041 unsigned int head, int len)
1042{
1043 vhost_add_used(vq, head, len);
1044 vhost_signal(dev, vq);
1045}
1046
1047/* OK, now we need to know about added descriptors. */
1048bool vhost_enable_notify(struct vhost_virtqueue *vq)
1049{
1050 u16 avail_idx;
1051 int r;
1052 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
1053 return false;
1054 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
1055 r = put_user(vq->used_flags, &vq->used->flags);
1056 if (r) {
1057 vq_err(vq, "Failed to enable notification at %p: %d\n",
1058 &vq->used->flags, r);
1059 return false;
1060 }
1061 /* They could have slipped one in as we were doing that: make
1062 * sure it's written, then check again. */
1063 mb();
1064 r = get_user(avail_idx, &vq->avail->idx);
1065 if (r) {
1066 vq_err(vq, "Failed to check avail idx at %p: %d\n",
1067 &vq->avail->idx, r);
1068 return false;
1069 }
1070
1071 return avail_idx != vq->last_avail_idx;
1072}
1073
1074/* We don't need to be notified again. */
1075void vhost_disable_notify(struct vhost_virtqueue *vq)
1076{
1077 int r;
1078 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
1079 return;
1080 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
1081 r = put_user(vq->used_flags, &vq->used->flags);
1082 if (r)
1083 vq_err(vq, "Failed to enable notification at %p: %d\n",
1084 &vq->used->flags, r);
1085}
1086
1087int vhost_init(void)
1088{
1089 vhost_workqueue = create_singlethread_workqueue("vhost");
1090 if (!vhost_workqueue)
1091 return -ENOMEM;
1092 return 0;
1093}
1094
1095void vhost_cleanup(void)
1096{
1097 destroy_workqueue(vhost_workqueue);
1098}
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
new file mode 100644
index 000000000000..44591ba9b07a
--- /dev/null
+++ b/drivers/vhost/vhost.h
@@ -0,0 +1,161 @@
1#ifndef _VHOST_H
2#define _VHOST_H
3
4#include <linux/eventfd.h>
5#include <linux/vhost.h>
6#include <linux/mm.h>
7#include <linux/mutex.h>
8#include <linux/workqueue.h>
9#include <linux/poll.h>
10#include <linux/file.h>
11#include <linux/skbuff.h>
12#include <linux/uio.h>
13#include <linux/virtio_config.h>
14#include <linux/virtio_ring.h>
15
16struct vhost_device;
17
18enum {
19 /* Enough place for all fragments, head, and virtio net header. */
20 VHOST_NET_MAX_SG = MAX_SKB_FRAGS + 2,
21};
22
23/* Poll a file (eventfd or socket) */
24/* Note: there's nothing vhost specific about this structure. */
25struct vhost_poll {
26 poll_table table;
27 wait_queue_head_t *wqh;
28 wait_queue_t wait;
29 /* struct which will handle all actual work. */
30 struct work_struct work;
31 unsigned long mask;
32};
33
34void vhost_poll_init(struct vhost_poll *poll, work_func_t func,
35 unsigned long mask);
36void vhost_poll_start(struct vhost_poll *poll, struct file *file);
37void vhost_poll_stop(struct vhost_poll *poll);
38void vhost_poll_flush(struct vhost_poll *poll);
39void vhost_poll_queue(struct vhost_poll *poll);
40
41struct vhost_log {
42 u64 addr;
43 u64 len;
44};
45
46/* The virtqueue structure describes a queue attached to a device. */
47struct vhost_virtqueue {
48 struct vhost_dev *dev;
49
50 /* The actual ring of buffers. */
51 struct mutex mutex;
52 unsigned int num;
53 struct vring_desc __user *desc;
54 struct vring_avail __user *avail;
55 struct vring_used __user *used;
56 struct file *kick;
57 struct file *call;
58 struct file *error;
59 struct eventfd_ctx *call_ctx;
60 struct eventfd_ctx *error_ctx;
61 struct eventfd_ctx *log_ctx;
62
63 struct vhost_poll poll;
64
65 /* The routine to call when the Guest pings us, or timeout. */
66 work_func_t handle_kick;
67
68 /* Last available index we saw. */
69 u16 last_avail_idx;
70
71 /* Caches available index value from user. */
72 u16 avail_idx;
73
74 /* Last index we used. */
75 u16 last_used_idx;
76
77 /* Used flags */
78 u16 used_flags;
79
80 /* Log writes to used structure. */
81 bool log_used;
82 u64 log_addr;
83
84 struct iovec indirect[VHOST_NET_MAX_SG];
85 struct iovec iov[VHOST_NET_MAX_SG];
86 struct iovec hdr[VHOST_NET_MAX_SG];
87 size_t hdr_size;
88 /* We use a kind of RCU to access private pointer.
89 * All readers access it from workqueue, which makes it possible to
90 * flush the workqueue instead of synchronize_rcu. Therefore readers do
91 * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
92 * work item execution acts instead of rcu_read_lock() and the end of
93 * work item execution acts instead of rcu_read_lock().
94 * Writers use virtqueue mutex. */
95 void *private_data;
96 /* Log write descriptors */
97 void __user *log_base;
98 struct vhost_log log[VHOST_NET_MAX_SG];
99};
100
101struct vhost_dev {
102 /* Readers use RCU to access memory table pointer
103 * log base pointer and features.
104 * Writers use mutex below.*/
105 struct vhost_memory *memory;
106 struct mm_struct *mm;
107 struct mutex mutex;
108 unsigned acked_features;
109 struct vhost_virtqueue *vqs;
110 int nvqs;
111 struct file *log_file;
112 struct eventfd_ctx *log_ctx;
113};
114
115long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
116long vhost_dev_check_owner(struct vhost_dev *);
117long vhost_dev_reset_owner(struct vhost_dev *);
118void vhost_dev_cleanup(struct vhost_dev *);
119long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
120int vhost_vq_access_ok(struct vhost_virtqueue *vq);
121int vhost_log_access_ok(struct vhost_dev *);
122
123unsigned vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
124 struct iovec iov[], unsigned int iov_count,
125 unsigned int *out_num, unsigned int *in_num,
126 struct vhost_log *log, unsigned int *log_num);
127void vhost_discard_vq_desc(struct vhost_virtqueue *);
128
129int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
130void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
131void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
132 unsigned int head, int len);
133void vhost_disable_notify(struct vhost_virtqueue *);
134bool vhost_enable_notify(struct vhost_virtqueue *);
135
136int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
137 unsigned int log_num, u64 len);
138
139int vhost_init(void);
140void vhost_cleanup(void);
141
142#define vq_err(vq, fmt, ...) do { \
143 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
144 if ((vq)->error_ctx) \
145 eventfd_signal((vq)->error_ctx, 1);\
146 } while (0)
147
148enum {
149 VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) |
150 (1 << VIRTIO_RING_F_INDIRECT_DESC) |
151 (1 << VHOST_F_LOG_ALL) |
152 (1 << VHOST_NET_F_VIRTIO_NET_HDR),
153};
154
155static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
156{
157 unsigned acked_features = rcu_dereference(dev->acked_features);
158 return acked_features & (1 << bit);
159}
160
161#endif
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-20 14:11:39 -0500