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1 | /* |
2 | * Multifd zlib compression implementation | |
3 | * | |
4 | * Copyright (c) 2020 Red Hat Inc | |
5 | * | |
6 | * Authors: | |
7 | * Juan Quintela <quintela@redhat.com> | |
8 | * | |
9 | * This work is licensed under the terms of the GNU GPL, version 2 or later. | |
10 | * See the COPYING file in the top-level directory. | |
11 | */ | |
12 | ||
13 | #include "qemu/osdep.h" | |
14 | #include <zstd.h> | |
15 | #include "qemu/rcu.h" | |
16 | #include "exec/target_page.h" | |
17 | #include "qapi/error.h" | |
18 | #include "migration.h" | |
19 | #include "trace.h" | |
20 | #include "multifd.h" | |
21 | ||
22 | struct zstd_data { | |
23 | /* stream for compression */ | |
24 | ZSTD_CStream *zcs; | |
25 | /* stream for decompression */ | |
26 | ZSTD_DStream *zds; | |
27 | /* buffers */ | |
28 | ZSTD_inBuffer in; | |
29 | ZSTD_outBuffer out; | |
30 | /* compressed buffer */ | |
31 | uint8_t *zbuff; | |
32 | /* size of compressed buffer */ | |
33 | uint32_t zbuff_len; | |
34 | }; | |
35 | ||
36 | /* Multifd zstd compression */ | |
37 | ||
38 | /** | |
39 | * zstd_send_setup: setup send side | |
40 | * | |
41 | * Setup each channel with zstd compression. | |
42 | * | |
43 | * Returns 0 for success or -1 for error | |
44 | * | |
45 | * @p: Params for the channel that we are using | |
46 | * @errp: pointer to an error | |
47 | */ | |
48 | static int zstd_send_setup(MultiFDSendParams *p, Error **errp) | |
49 | { | |
50 | uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size(); | |
51 | struct zstd_data *z = g_new0(struct zstd_data, 1); | |
52 | int res; | |
53 | ||
54 | p->data = z; | |
55 | z->zcs = ZSTD_createCStream(); | |
56 | if (!z->zcs) { | |
57 | g_free(z); | |
58 | error_setg(errp, "multifd %d: zstd createCStream failed", p->id); | |
59 | return -1; | |
60 | } | |
61 | ||
62 | res = ZSTD_initCStream(z->zcs, migrate_multifd_zstd_level()); | |
63 | if (ZSTD_isError(res)) { | |
64 | ZSTD_freeCStream(z->zcs); | |
65 | g_free(z); | |
66 | error_setg(errp, "multifd %d: initCStream failed with error %s", | |
67 | p->id, ZSTD_getErrorName(res)); | |
68 | return -1; | |
69 | } | |
70 | /* We will never have more than page_count pages */ | |
71 | z->zbuff_len = page_count * qemu_target_page_size(); | |
72 | z->zbuff_len *= 2; | |
73 | z->zbuff = g_try_malloc(z->zbuff_len); | |
74 | if (!z->zbuff) { | |
75 | ZSTD_freeCStream(z->zcs); | |
76 | g_free(z); | |
77 | error_setg(errp, "multifd %d: out of memory for zbuff", p->id); | |
78 | return -1; | |
79 | } | |
80 | return 0; | |
81 | } | |
82 | ||
83 | /** | |
84 | * zstd_send_cleanup: cleanup send side | |
85 | * | |
86 | * Close the channel and return memory. | |
87 | * | |
88 | * @p: Params for the channel that we are using | |
89 | */ | |
90 | static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp) | |
91 | { | |
92 | struct zstd_data *z = p->data; | |
93 | ||
94 | ZSTD_freeCStream(z->zcs); | |
95 | z->zcs = NULL; | |
96 | g_free(z->zbuff); | |
97 | z->zbuff = NULL; | |
98 | g_free(p->data); | |
99 | p->data = NULL; | |
100 | } | |
101 | ||
102 | /** | |
103 | * zstd_send_prepare: prepare date to be able to send | |
104 | * | |
105 | * Create a compressed buffer with all the pages that we are going to | |
106 | * send. | |
107 | * | |
108 | * Returns 0 for success or -1 for error | |
109 | * | |
110 | * @p: Params for the channel that we are using | |
111 | * @used: number of pages used | |
112 | */ | |
113 | static int zstd_send_prepare(MultiFDSendParams *p, uint32_t used, Error **errp) | |
114 | { | |
115 | struct iovec *iov = p->pages->iov; | |
116 | struct zstd_data *z = p->data; | |
117 | int ret; | |
118 | uint32_t i; | |
119 | ||
120 | z->out.dst = z->zbuff; | |
121 | z->out.size = z->zbuff_len; | |
122 | z->out.pos = 0; | |
123 | ||
124 | for (i = 0; i < used; i++) { | |
125 | ZSTD_EndDirective flush = ZSTD_e_continue; | |
126 | ||
127 | if (i == used - 1) { | |
128 | flush = ZSTD_e_flush; | |
129 | } | |
130 | z->in.src = iov[i].iov_base; | |
131 | z->in.size = iov[i].iov_len; | |
132 | z->in.pos = 0; | |
133 | ||
134 | /* | |
135 | * Welcome to compressStream2 semantics | |
136 | * | |
137 | * We need to loop while: | |
138 | * - return is > 0 | |
139 | * - there is input available | |
140 | * - there is output space free | |
141 | */ | |
142 | do { | |
143 | ret = ZSTD_compressStream2(z->zcs, &z->out, &z->in, flush); | |
144 | } while (ret > 0 && (z->in.size - z->in.pos > 0) | |
145 | && (z->out.size - z->out.pos > 0)); | |
146 | if (ret > 0 && (z->in.size - z->in.pos > 0)) { | |
147 | error_setg(errp, "multifd %d: compressStream buffer too small", | |
148 | p->id); | |
149 | return -1; | |
150 | } | |
151 | if (ZSTD_isError(ret)) { | |
152 | error_setg(errp, "multifd %d: compressStream error %s", | |
153 | p->id, ZSTD_getErrorName(ret)); | |
154 | return -1; | |
155 | } | |
156 | } | |
157 | p->next_packet_size = z->out.pos; | |
158 | p->flags |= MULTIFD_FLAG_ZSTD; | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
163 | /** | |
164 | * zstd_send_write: do the actual write of the data | |
165 | * | |
166 | * Do the actual write of the comprresed buffer. | |
167 | * | |
168 | * Returns 0 for success or -1 for error | |
169 | * | |
170 | * @p: Params for the channel that we are using | |
171 | * @used: number of pages used | |
172 | * @errp: pointer to an error | |
173 | */ | |
174 | static int zstd_send_write(MultiFDSendParams *p, uint32_t used, Error **errp) | |
175 | { | |
176 | struct zstd_data *z = p->data; | |
177 | ||
178 | return qio_channel_write_all(p->c, (void *)z->zbuff, p->next_packet_size, | |
179 | errp); | |
180 | } | |
181 | ||
182 | /** | |
183 | * zstd_recv_setup: setup receive side | |
184 | * | |
185 | * Create the compressed channel and buffer. | |
186 | * | |
187 | * Returns 0 for success or -1 for error | |
188 | * | |
189 | * @p: Params for the channel that we are using | |
190 | * @errp: pointer to an error | |
191 | */ | |
192 | static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp) | |
193 | { | |
194 | uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size(); | |
195 | struct zstd_data *z = g_new0(struct zstd_data, 1); | |
196 | int ret; | |
197 | ||
198 | p->data = z; | |
199 | z->zds = ZSTD_createDStream(); | |
200 | if (!z->zds) { | |
201 | g_free(z); | |
202 | error_setg(errp, "multifd %d: zstd createDStream failed", p->id); | |
203 | return -1; | |
204 | } | |
205 | ||
206 | ret = ZSTD_initDStream(z->zds); | |
207 | if (ZSTD_isError(ret)) { | |
208 | ZSTD_freeDStream(z->zds); | |
209 | g_free(z); | |
210 | error_setg(errp, "multifd %d: initDStream failed with error %s", | |
211 | p->id, ZSTD_getErrorName(ret)); | |
212 | return -1; | |
213 | } | |
214 | ||
215 | /* We will never have more than page_count pages */ | |
216 | z->zbuff_len = page_count * qemu_target_page_size(); | |
217 | /* We know compression "could" use more space */ | |
218 | z->zbuff_len *= 2; | |
219 | z->zbuff = g_try_malloc(z->zbuff_len); | |
220 | if (!z->zbuff) { | |
221 | ZSTD_freeDStream(z->zds); | |
222 | g_free(z); | |
223 | error_setg(errp, "multifd %d: out of memory for zbuff", p->id); | |
224 | return -1; | |
225 | } | |
226 | return 0; | |
227 | } | |
228 | ||
229 | /** | |
230 | * zstd_recv_cleanup: setup receive side | |
231 | * | |
232 | * For no compression this function does nothing. | |
233 | * | |
234 | * @p: Params for the channel that we are using | |
235 | */ | |
236 | static void zstd_recv_cleanup(MultiFDRecvParams *p) | |
237 | { | |
238 | struct zstd_data *z = p->data; | |
239 | ||
240 | ZSTD_freeDStream(z->zds); | |
241 | z->zds = NULL; | |
242 | g_free(z->zbuff); | |
243 | z->zbuff = NULL; | |
244 | g_free(p->data); | |
245 | p->data = NULL; | |
246 | } | |
247 | ||
248 | /** | |
249 | * zstd_recv_pages: read the data from the channel into actual pages | |
250 | * | |
251 | * Read the compressed buffer, and uncompress it into the actual | |
252 | * pages. | |
253 | * | |
254 | * Returns 0 for success or -1 for error | |
255 | * | |
256 | * @p: Params for the channel that we are using | |
257 | * @used: number of pages used | |
258 | * @errp: pointer to an error | |
259 | */ | |
260 | static int zstd_recv_pages(MultiFDRecvParams *p, uint32_t used, Error **errp) | |
261 | { | |
262 | uint32_t in_size = p->next_packet_size; | |
263 | uint32_t out_size = 0; | |
264 | uint32_t expected_size = used * qemu_target_page_size(); | |
265 | uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK; | |
266 | struct zstd_data *z = p->data; | |
267 | int ret; | |
268 | int i; | |
269 | ||
270 | if (flags != MULTIFD_FLAG_ZSTD) { | |
271 | error_setg(errp, "multifd %d: flags received %x flags expected %x", | |
272 | p->id, flags, MULTIFD_FLAG_ZSTD); | |
273 | return -1; | |
274 | } | |
275 | ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp); | |
276 | ||
277 | if (ret != 0) { | |
278 | return ret; | |
279 | } | |
280 | ||
281 | z->in.src = z->zbuff; | |
282 | z->in.size = in_size; | |
283 | z->in.pos = 0; | |
284 | ||
285 | for (i = 0; i < used; i++) { | |
286 | struct iovec *iov = &p->pages->iov[i]; | |
287 | ||
288 | z->out.dst = iov->iov_base; | |
289 | z->out.size = iov->iov_len; | |
290 | z->out.pos = 0; | |
291 | ||
292 | /* | |
293 | * Welcome to decompressStream semantics | |
294 | * | |
295 | * We need to loop while: | |
296 | * - return is > 0 | |
297 | * - there is input available | |
298 | * - we haven't put out a full page | |
299 | */ | |
300 | do { | |
301 | ret = ZSTD_decompressStream(z->zds, &z->out, &z->in); | |
302 | } while (ret > 0 && (z->in.size - z->in.pos > 0) | |
303 | && (z->out.pos < iov->iov_len)); | |
304 | if (ret > 0 && (z->out.pos < iov->iov_len)) { | |
305 | error_setg(errp, "multifd %d: decompressStream buffer too small", | |
306 | p->id); | |
307 | return -1; | |
308 | } | |
309 | if (ZSTD_isError(ret)) { | |
310 | error_setg(errp, "multifd %d: decompressStream returned %s", | |
311 | p->id, ZSTD_getErrorName(ret)); | |
312 | return ret; | |
313 | } | |
314 | out_size += z->out.pos; | |
315 | } | |
316 | if (out_size != expected_size) { | |
317 | error_setg(errp, "multifd %d: packet size received %d size expected %d", | |
318 | p->id, out_size, expected_size); | |
319 | return -1; | |
320 | } | |
321 | return 0; | |
322 | } | |
323 | ||
324 | static MultiFDMethods multifd_zstd_ops = { | |
325 | .send_setup = zstd_send_setup, | |
326 | .send_cleanup = zstd_send_cleanup, | |
327 | .send_prepare = zstd_send_prepare, | |
328 | .send_write = zstd_send_write, | |
329 | .recv_setup = zstd_recv_setup, | |
330 | .recv_cleanup = zstd_recv_cleanup, | |
331 | .recv_pages = zstd_recv_pages | |
332 | }; | |
333 | ||
334 | static void multifd_zstd_register(void) | |
335 | { | |
336 | multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops); | |
337 | } | |
338 | ||
339 | migration_init(multifd_zstd_register); |