]>
Commit | Line | Data |
---|---|---|
3e7ee490 HJ |
1 | /* |
2 | * | |
3 | * Copyright (c) 2009, Microsoft Corporation. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms and conditions of the GNU General Public License, | |
7 | * version 2, as published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
12 | * more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License along with | |
15 | * this program; if not, write to the Free Software Foundation, Inc., 59 Temple | |
16 | * Place - Suite 330, Boston, MA 02111-1307 USA. | |
17 | * | |
18 | * Authors: | |
19 | * Haiyang Zhang <haiyangz@microsoft.com> | |
20 | * Hank Janssen <hjanssen@microsoft.com> | |
b2a5a585 | 21 | * K. Y. Srinivasan <kys@microsoft.com> |
3e7ee490 HJ |
22 | * |
23 | */ | |
0a46618d | 24 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
3e7ee490 | 25 | |
a0086dc5 GKH |
26 | #include <linux/kernel.h> |
27 | #include <linux/mm.h> | |
46a97191 | 28 | #include <linux/hyperv.h> |
011a7c3c | 29 | #include <linux/uio.h> |
9988ce68 VK |
30 | #include <linux/vmalloc.h> |
31 | #include <linux/slab.h> | |
3f335ea2 | 32 | |
0f2a6619 | 33 | #include "hyperv_vmbus.h" |
3e7ee490 | 34 | |
6fdf3b21 S |
35 | void hv_begin_read(struct hv_ring_buffer_info *rbi) |
36 | { | |
37 | rbi->ring_buffer->interrupt_mask = 1; | |
dcd0eeca | 38 | virt_mb(); |
6fdf3b21 S |
39 | } |
40 | ||
41 | u32 hv_end_read(struct hv_ring_buffer_info *rbi) | |
42 | { | |
6fdf3b21 S |
43 | |
44 | rbi->ring_buffer->interrupt_mask = 0; | |
dcd0eeca | 45 | virt_mb(); |
6fdf3b21 S |
46 | |
47 | /* | |
48 | * Now check to see if the ring buffer is still empty. | |
49 | * If it is not, we raced and we need to process new | |
50 | * incoming messages. | |
51 | */ | |
a6341f00 | 52 | return hv_get_bytes_to_read(rbi); |
6fdf3b21 S |
53 | } |
54 | ||
98fa8cf4 S |
55 | /* |
56 | * When we write to the ring buffer, check if the host needs to | |
57 | * be signaled. Here is the details of this protocol: | |
58 | * | |
59 | * 1. The host guarantees that while it is draining the | |
60 | * ring buffer, it will set the interrupt_mask to | |
61 | * indicate it does not need to be interrupted when | |
62 | * new data is placed. | |
63 | * | |
64 | * 2. The host guarantees that it will completely drain | |
65 | * the ring buffer before exiting the read loop. Further, | |
66 | * once the ring buffer is empty, it will clear the | |
67 | * interrupt_mask and re-check to see if new data has | |
68 | * arrived. | |
1f6ee4e7 S |
69 | * |
70 | * KYS: Oct. 30, 2016: | |
71 | * It looks like Windows hosts have logic to deal with DOS attacks that | |
72 | * can be triggered if it receives interrupts when it is not expecting | |
73 | * the interrupt. The host expects interrupts only when the ring | |
74 | * transitions from empty to non-empty (or full to non full on the guest | |
75 | * to host ring). | |
76 | * So, base the signaling decision solely on the ring state until the | |
77 | * host logic is fixed. | |
98fa8cf4 S |
78 | */ |
79 | ||
1f6ee4e7 S |
80 | static void hv_signal_on_write(u32 old_write, struct vmbus_channel *channel, |
81 | bool kick_q) | |
98fa8cf4 | 82 | { |
1f6ee4e7 S |
83 | struct hv_ring_buffer_info *rbi = &channel->outbound; |
84 | ||
dcd0eeca | 85 | virt_mb(); |
d45faaee | 86 | if (READ_ONCE(rbi->ring_buffer->interrupt_mask)) |
1f6ee4e7 | 87 | return; |
98fa8cf4 | 88 | |
e91e84fa | 89 | /* check interrupt_mask before read_index */ |
dcd0eeca | 90 | virt_rmb(); |
98fa8cf4 S |
91 | /* |
92 | * This is the only case we need to signal when the | |
93 | * ring transitions from being empty to non-empty. | |
94 | */ | |
d45faaee | 95 | if (old_write == READ_ONCE(rbi->ring_buffer->read_index)) |
1f6ee4e7 | 96 | vmbus_setevent(channel); |
98fa8cf4 | 97 | |
1f6ee4e7 | 98 | return; |
98fa8cf4 S |
99 | } |
100 | ||
822f18d4 | 101 | /* Get the next write location for the specified ring buffer. */ |
4d643114 | 102 | static inline u32 |
2b8a912e | 103 | hv_get_next_write_location(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 104 | { |
fc8c72eb | 105 | u32 next = ring_info->ring_buffer->write_index; |
3e7ee490 | 106 | |
3e7ee490 HJ |
107 | return next; |
108 | } | |
109 | ||
822f18d4 | 110 | /* Set the next write location for the specified ring buffer. */ |
3e7ee490 | 111 | static inline void |
2b8a912e | 112 | hv_set_next_write_location(struct hv_ring_buffer_info *ring_info, |
fc8c72eb | 113 | u32 next_write_location) |
3e7ee490 | 114 | { |
fc8c72eb | 115 | ring_info->ring_buffer->write_index = next_write_location; |
3e7ee490 HJ |
116 | } |
117 | ||
822f18d4 | 118 | /* Get the next read location for the specified ring buffer. */ |
4d643114 | 119 | static inline u32 |
2b8a912e | 120 | hv_get_next_read_location(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 121 | { |
fc8c72eb | 122 | u32 next = ring_info->ring_buffer->read_index; |
3e7ee490 | 123 | |
3e7ee490 HJ |
124 | return next; |
125 | } | |
126 | ||
b2a5a585 | 127 | /* |
b2a5a585 | 128 | * Get the next read location + offset for the specified ring buffer. |
822f18d4 | 129 | * This allows the caller to skip. |
b2a5a585 | 130 | */ |
4d643114 | 131 | static inline u32 |
2b8a912e | 132 | hv_get_next_readlocation_withoffset(struct hv_ring_buffer_info *ring_info, |
1ac58644 | 133 | u32 offset) |
3e7ee490 | 134 | { |
fc8c72eb | 135 | u32 next = ring_info->ring_buffer->read_index; |
3e7ee490 | 136 | |
fc8c72eb HZ |
137 | next += offset; |
138 | next %= ring_info->ring_datasize; | |
3e7ee490 HJ |
139 | |
140 | return next; | |
141 | } | |
142 | ||
822f18d4 | 143 | /* Set the next read location for the specified ring buffer. */ |
3e7ee490 | 144 | static inline void |
2b8a912e | 145 | hv_set_next_read_location(struct hv_ring_buffer_info *ring_info, |
fc8c72eb | 146 | u32 next_read_location) |
3e7ee490 | 147 | { |
fc8c72eb | 148 | ring_info->ring_buffer->read_index = next_read_location; |
ab028db4 | 149 | ring_info->priv_read_index = next_read_location; |
3e7ee490 HJ |
150 | } |
151 | ||
822f18d4 | 152 | /* Get the size of the ring buffer. */ |
4d643114 | 153 | static inline u32 |
2b8a912e | 154 | hv_get_ring_buffersize(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 155 | { |
fc8c72eb | 156 | return ring_info->ring_datasize; |
3e7ee490 HJ |
157 | } |
158 | ||
822f18d4 | 159 | /* Get the read and write indices as u64 of the specified ring buffer. */ |
59471438 | 160 | static inline u64 |
2b8a912e | 161 | hv_get_ring_bufferindices(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 162 | { |
fc8c72eb | 163 | return (u64)ring_info->ring_buffer->write_index << 32; |
3e7ee490 HJ |
164 | } |
165 | ||
8f1136ae | 166 | /* |
8f1136ae S |
167 | * Helper routine to copy to source from ring buffer. |
168 | * Assume there is enough room. Handles wrap-around in src case only!! | |
8f1136ae S |
169 | */ |
170 | static u32 hv_copyfrom_ringbuffer( | |
171 | struct hv_ring_buffer_info *ring_info, | |
172 | void *dest, | |
173 | u32 destlen, | |
174 | u32 start_read_offset) | |
175 | { | |
176 | void *ring_buffer = hv_get_ring_buffer(ring_info); | |
177 | u32 ring_buffer_size = hv_get_ring_buffersize(ring_info); | |
178 | ||
f24f0b49 | 179 | memcpy(dest, ring_buffer + start_read_offset, destlen); |
8f1136ae S |
180 | |
181 | start_read_offset += destlen; | |
182 | start_read_offset %= ring_buffer_size; | |
183 | ||
184 | return start_read_offset; | |
185 | } | |
186 | ||
187 | ||
7581578d | 188 | /* |
7581578d S |
189 | * Helper routine to copy from source to ring buffer. |
190 | * Assume there is enough room. Handles wrap-around in dest case only!! | |
7581578d S |
191 | */ |
192 | static u32 hv_copyto_ringbuffer( | |
fc8c72eb HZ |
193 | struct hv_ring_buffer_info *ring_info, |
194 | u32 start_write_offset, | |
195 | void *src, | |
7581578d S |
196 | u32 srclen) |
197 | { | |
198 | void *ring_buffer = hv_get_ring_buffer(ring_info); | |
199 | u32 ring_buffer_size = hv_get_ring_buffersize(ring_info); | |
f24f0b49 VK |
200 | |
201 | memcpy(ring_buffer + start_write_offset, src, srclen); | |
3e7ee490 | 202 | |
7581578d S |
203 | start_write_offset += srclen; |
204 | start_write_offset %= ring_buffer_size; | |
205 | ||
206 | return start_write_offset; | |
207 | } | |
3e7ee490 | 208 | |
822f18d4 | 209 | /* Get various debug metrics for the specified ring buffer. */ |
a75b61d5 | 210 | void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info, |
80682b7a | 211 | struct hv_ring_buffer_debug_info *debug_info) |
3e7ee490 | 212 | { |
fc8c72eb HZ |
213 | u32 bytes_avail_towrite; |
214 | u32 bytes_avail_toread; | |
3e7ee490 | 215 | |
fc8c72eb | 216 | if (ring_info->ring_buffer) { |
2b8a912e | 217 | hv_get_ringbuffer_availbytes(ring_info, |
fc8c72eb HZ |
218 | &bytes_avail_toread, |
219 | &bytes_avail_towrite); | |
3e7ee490 | 220 | |
fc8c72eb HZ |
221 | debug_info->bytes_avail_toread = bytes_avail_toread; |
222 | debug_info->bytes_avail_towrite = bytes_avail_towrite; | |
82f8bd40 | 223 | debug_info->current_read_index = |
fc8c72eb | 224 | ring_info->ring_buffer->read_index; |
82f8bd40 | 225 | debug_info->current_write_index = |
fc8c72eb | 226 | ring_info->ring_buffer->write_index; |
82f8bd40 | 227 | debug_info->current_interrupt_mask = |
fc8c72eb | 228 | ring_info->ring_buffer->interrupt_mask; |
3e7ee490 HJ |
229 | } |
230 | } | |
231 | ||
822f18d4 | 232 | /* Initialize the ring buffer. */ |
72a95cbc | 233 | int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info, |
9988ce68 | 234 | struct page *pages, u32 page_cnt) |
3e7ee490 | 235 | { |
9988ce68 VK |
236 | int i; |
237 | struct page **pages_wraparound; | |
238 | ||
239 | BUILD_BUG_ON((sizeof(struct hv_ring_buffer) != PAGE_SIZE)); | |
3e7ee490 | 240 | |
fc8c72eb | 241 | memset(ring_info, 0, sizeof(struct hv_ring_buffer_info)); |
3e7ee490 | 242 | |
9988ce68 VK |
243 | /* |
244 | * First page holds struct hv_ring_buffer, do wraparound mapping for | |
245 | * the rest. | |
246 | */ | |
247 | pages_wraparound = kzalloc(sizeof(struct page *) * (page_cnt * 2 - 1), | |
248 | GFP_KERNEL); | |
249 | if (!pages_wraparound) | |
250 | return -ENOMEM; | |
251 | ||
252 | pages_wraparound[0] = pages; | |
253 | for (i = 0; i < 2 * (page_cnt - 1); i++) | |
254 | pages_wraparound[i + 1] = &pages[i % (page_cnt - 1) + 1]; | |
255 | ||
256 | ring_info->ring_buffer = (struct hv_ring_buffer *) | |
257 | vmap(pages_wraparound, page_cnt * 2 - 1, VM_MAP, PAGE_KERNEL); | |
258 | ||
259 | kfree(pages_wraparound); | |
260 | ||
261 | ||
262 | if (!ring_info->ring_buffer) | |
263 | return -ENOMEM; | |
264 | ||
fc8c72eb HZ |
265 | ring_info->ring_buffer->read_index = |
266 | ring_info->ring_buffer->write_index = 0; | |
3e7ee490 | 267 | |
822f18d4 | 268 | /* Set the feature bit for enabling flow control. */ |
046c7911 S |
269 | ring_info->ring_buffer->feature_bits.value = 1; |
270 | ||
9988ce68 VK |
271 | ring_info->ring_size = page_cnt << PAGE_SHIFT; |
272 | ring_info->ring_datasize = ring_info->ring_size - | |
273 | sizeof(struct hv_ring_buffer); | |
3e7ee490 | 274 | |
fc8c72eb | 275 | spin_lock_init(&ring_info->ring_lock); |
3e7ee490 HJ |
276 | |
277 | return 0; | |
278 | } | |
279 | ||
822f18d4 | 280 | /* Cleanup the ring buffer. */ |
2dba688b | 281 | void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info) |
3e7ee490 | 282 | { |
9988ce68 | 283 | vunmap(ring_info->ring_buffer); |
3e7ee490 HJ |
284 | } |
285 | ||
822f18d4 | 286 | /* Write to the ring buffer. */ |
1f6ee4e7 S |
287 | int hv_ringbuffer_write(struct vmbus_channel *channel, |
288 | struct kvec *kv_list, u32 kv_count, bool lock, | |
289 | bool kick_q) | |
3e7ee490 | 290 | { |
4408f531 | 291 | int i = 0; |
fc8c72eb | 292 | u32 bytes_avail_towrite; |
fc8c72eb | 293 | u32 totalbytes_towrite = 0; |
3e7ee490 | 294 | |
66a60543 | 295 | u32 next_write_location; |
98fa8cf4 | 296 | u32 old_write; |
fc8c72eb | 297 | u64 prev_indices = 0; |
fe760e4d | 298 | unsigned long flags = 0; |
1f6ee4e7 | 299 | struct hv_ring_buffer_info *outring_info = &channel->outbound; |
3e7ee490 | 300 | |
011a7c3c S |
301 | for (i = 0; i < kv_count; i++) |
302 | totalbytes_towrite += kv_list[i].iov_len; | |
3e7ee490 | 303 | |
fc8c72eb | 304 | totalbytes_towrite += sizeof(u64); |
3e7ee490 | 305 | |
fe760e4d S |
306 | if (lock) |
307 | spin_lock_irqsave(&outring_info->ring_lock, flags); | |
3e7ee490 | 308 | |
a6341f00 | 309 | bytes_avail_towrite = hv_get_bytes_to_write(outring_info); |
3e7ee490 | 310 | |
822f18d4 VK |
311 | /* |
312 | * If there is only room for the packet, assume it is full. | |
313 | * Otherwise, the next time around, we think the ring buffer | |
314 | * is empty since the read index == write index. | |
315 | */ | |
fc8c72eb | 316 | if (bytes_avail_towrite <= totalbytes_towrite) { |
fe760e4d S |
317 | if (lock) |
318 | spin_unlock_irqrestore(&outring_info->ring_lock, flags); | |
d2598f01 | 319 | return -EAGAIN; |
3e7ee490 HJ |
320 | } |
321 | ||
454f18a9 | 322 | /* Write to the ring buffer */ |
2b8a912e | 323 | next_write_location = hv_get_next_write_location(outring_info); |
3e7ee490 | 324 | |
98fa8cf4 S |
325 | old_write = next_write_location; |
326 | ||
011a7c3c | 327 | for (i = 0; i < kv_count; i++) { |
2b8a912e | 328 | next_write_location = hv_copyto_ringbuffer(outring_info, |
fc8c72eb | 329 | next_write_location, |
011a7c3c S |
330 | kv_list[i].iov_base, |
331 | kv_list[i].iov_len); | |
3e7ee490 HJ |
332 | } |
333 | ||
454f18a9 | 334 | /* Set previous packet start */ |
2b8a912e | 335 | prev_indices = hv_get_ring_bufferindices(outring_info); |
3e7ee490 | 336 | |
2b8a912e | 337 | next_write_location = hv_copyto_ringbuffer(outring_info, |
fc8c72eb HZ |
338 | next_write_location, |
339 | &prev_indices, | |
b219b3f7 | 340 | sizeof(u64)); |
3e7ee490 | 341 | |
98fa8cf4 | 342 | /* Issue a full memory barrier before updating the write index */ |
dcd0eeca | 343 | virt_mb(); |
3e7ee490 | 344 | |
454f18a9 | 345 | /* Now, update the write location */ |
2b8a912e | 346 | hv_set_next_write_location(outring_info, next_write_location); |
3e7ee490 | 347 | |
3e7ee490 | 348 | |
fe760e4d S |
349 | if (lock) |
350 | spin_unlock_irqrestore(&outring_info->ring_lock, flags); | |
98fa8cf4 | 351 | |
1f6ee4e7 | 352 | hv_signal_on_write(old_write, channel, kick_q); |
3e7ee490 HJ |
353 | return 0; |
354 | } | |
355 | ||
3372592a | 356 | int hv_ringbuffer_read(struct vmbus_channel *channel, |
940b68e2 | 357 | void *buffer, u32 buflen, u32 *buffer_actual_len, |
3372592a | 358 | u64 *requestid, bool raw) |
3e7ee490 | 359 | { |
fc8c72eb HZ |
360 | u32 bytes_avail_toread; |
361 | u32 next_read_location = 0; | |
362 | u64 prev_indices = 0; | |
940b68e2 VK |
363 | struct vmpacket_descriptor desc; |
364 | u32 offset; | |
365 | u32 packetlen; | |
366 | int ret = 0; | |
3372592a | 367 | struct hv_ring_buffer_info *inring_info = &channel->inbound; |
3e7ee490 | 368 | |
fc8c72eb | 369 | if (buflen <= 0) |
a16e1485 | 370 | return -EINVAL; |
3e7ee490 | 371 | |
3e7ee490 | 372 | |
940b68e2 VK |
373 | *buffer_actual_len = 0; |
374 | *requestid = 0; | |
375 | ||
a6341f00 | 376 | bytes_avail_toread = hv_get_bytes_to_read(inring_info); |
454f18a9 | 377 | /* Make sure there is something to read */ |
940b68e2 VK |
378 | if (bytes_avail_toread < sizeof(desc)) { |
379 | /* | |
380 | * No error is set when there is even no header, drivers are | |
381 | * supposed to analyze buffer_actual_len. | |
382 | */ | |
3eba9a77 | 383 | return ret; |
940b68e2 | 384 | } |
3e7ee490 | 385 | |
940b68e2 VK |
386 | next_read_location = hv_get_next_read_location(inring_info); |
387 | next_read_location = hv_copyfrom_ringbuffer(inring_info, &desc, | |
388 | sizeof(desc), | |
389 | next_read_location); | |
390 | ||
391 | offset = raw ? 0 : (desc.offset8 << 3); | |
392 | packetlen = (desc.len8 << 3) - offset; | |
393 | *buffer_actual_len = packetlen; | |
394 | *requestid = desc.trans_id; | |
395 | ||
3eba9a77 S |
396 | if (bytes_avail_toread < packetlen + offset) |
397 | return -EAGAIN; | |
940b68e2 | 398 | |
3eba9a77 S |
399 | if (packetlen > buflen) |
400 | return -ENOBUFS; | |
3e7ee490 | 401 | |
1ac58644 | 402 | next_read_location = |
2b8a912e | 403 | hv_get_next_readlocation_withoffset(inring_info, offset); |
3e7ee490 | 404 | |
2b8a912e | 405 | next_read_location = hv_copyfrom_ringbuffer(inring_info, |
fc8c72eb | 406 | buffer, |
940b68e2 | 407 | packetlen, |
fc8c72eb | 408 | next_read_location); |
3e7ee490 | 409 | |
2b8a912e | 410 | next_read_location = hv_copyfrom_ringbuffer(inring_info, |
fc8c72eb | 411 | &prev_indices, |
4408f531 | 412 | sizeof(u64), |
fc8c72eb | 413 | next_read_location); |
3e7ee490 | 414 | |
822f18d4 VK |
415 | /* |
416 | * Make sure all reads are done before we update the read index since | |
417 | * the writer may start writing to the read area once the read index | |
418 | * is updated. | |
419 | */ | |
dcd0eeca | 420 | virt_mb(); |
3e7ee490 | 421 | |
454f18a9 | 422 | /* Update the read index */ |
2b8a912e | 423 | hv_set_next_read_location(inring_info, next_read_location); |
3e7ee490 | 424 | |
3372592a | 425 | hv_signal_on_read(channel); |
c2b8e520 | 426 | |
940b68e2 | 427 | return ret; |
b5f53dde | 428 | } |