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/ramblock.h" 17 #include "exec/target_page.h" 18 #include "qapi/error.h" 19 #include "migration.h" 20 #include "trace.h" 21 #include "options.h" 22 #include "multifd.h" 23 24 struct zstd_data { 25 /* stream for compression */ 26 ZSTD_CStream *zcs; 27 /* stream for decompression */ 28 ZSTD_DStream *zds; 29 /* buffers */ 30 ZSTD_inBuffer in; 31 ZSTD_outBuffer out; 32 /* compressed buffer */ 33 uint8_t *zbuff; 34 /* size of compressed buffer */ 35 uint32_t zbuff_len; 36 }; 37 38 /* Multifd zstd compression */ 39 40 /** 41 * zstd_send_setup: setup send side 42 * 43 * Setup each channel with zstd compression. 44 * 45 * Returns 0 for success or -1 for error 46 * 47 * @p: Params for the channel that we are using 48 * @errp: pointer to an error 49 */ 50 static int zstd_send_setup(MultiFDSendParams *p, Error **errp) 51 { 52 struct zstd_data *z = g_new0(struct zstd_data, 1); 53 int res; 54 55 p->data = z; 56 z->zcs = ZSTD_createCStream(); 57 if (!z->zcs) { 58 g_free(z); 59 error_setg(errp, "multifd %u: zstd createCStream failed", p->id); 60 return -1; 61 } 62 63 res = ZSTD_initCStream(z->zcs, migrate_multifd_zstd_level()); 64 if (ZSTD_isError(res)) { 65 ZSTD_freeCStream(z->zcs); 66 g_free(z); 67 error_setg(errp, "multifd %u: initCStream failed with error %s", 68 p->id, ZSTD_getErrorName(res)); 69 return -1; 70 } 71 /* This is the maxium size of the compressed buffer */ 72 z->zbuff_len = ZSTD_compressBound(MULTIFD_PACKET_SIZE); 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 %u: 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 * @errp: pointer to an error 90 */ 91 static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp) 92 { 93 struct zstd_data *z = p->data; 94 95 ZSTD_freeCStream(z->zcs); 96 z->zcs = NULL; 97 g_free(z->zbuff); 98 z->zbuff = NULL; 99 g_free(p->data); 100 p->data = NULL; 101 } 102 103 /** 104 * zstd_send_prepare: prepare date to be able to send 105 * 106 * Create a compressed buffer with all the pages that we are going to 107 * send. 108 * 109 * Returns 0 for success or -1 for error 110 * 111 * @p: Params for the channel that we are using 112 * @errp: pointer to an error 113 */ 114 static int zstd_send_prepare(MultiFDSendParams *p, Error **errp) 115 { 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 < p->normal_num; i++) { 125 ZSTD_EndDirective flush = ZSTD_e_continue; 126 127 if (i == p->normal_num - 1) { 128 flush = ZSTD_e_flush; 129 } 130 z->in.src = p->pages->block->host + p->normal[i]; 131 z->in.size = p->page_size; 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 %u: compressStream buffer too small", 148 p->id); 149 return -1; 150 } 151 if (ZSTD_isError(ret)) { 152 error_setg(errp, "multifd %u: compressStream error %s", 153 p->id, ZSTD_getErrorName(ret)); 154 return -1; 155 } 156 } 157 p->iov[p->iovs_num].iov_base = z->zbuff; 158 p->iov[p->iovs_num].iov_len = z->out.pos; 159 p->iovs_num++; 160 p->next_packet_size = z->out.pos; 161 p->flags |= MULTIFD_FLAG_ZSTD; 162 163 return 0; 164 } 165 166 /** 167 * zstd_recv_setup: setup receive side 168 * 169 * Create the compressed channel and buffer. 170 * 171 * Returns 0 for success or -1 for error 172 * 173 * @p: Params for the channel that we are using 174 * @errp: pointer to an error 175 */ 176 static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp) 177 { 178 struct zstd_data *z = g_new0(struct zstd_data, 1); 179 int ret; 180 181 p->data = z; 182 z->zds = ZSTD_createDStream(); 183 if (!z->zds) { 184 g_free(z); 185 error_setg(errp, "multifd %u: zstd createDStream failed", p->id); 186 return -1; 187 } 188 189 ret = ZSTD_initDStream(z->zds); 190 if (ZSTD_isError(ret)) { 191 ZSTD_freeDStream(z->zds); 192 g_free(z); 193 error_setg(errp, "multifd %u: initDStream failed with error %s", 194 p->id, ZSTD_getErrorName(ret)); 195 return -1; 196 } 197 198 /* To be safe, we reserve twice the size of the packet */ 199 z->zbuff_len = MULTIFD_PACKET_SIZE * 2; 200 z->zbuff = g_try_malloc(z->zbuff_len); 201 if (!z->zbuff) { 202 ZSTD_freeDStream(z->zds); 203 g_free(z); 204 error_setg(errp, "multifd %u: out of memory for zbuff", p->id); 205 return -1; 206 } 207 return 0; 208 } 209 210 /** 211 * zstd_recv_cleanup: setup receive side 212 * 213 * For no compression this function does nothing. 214 * 215 * @p: Params for the channel that we are using 216 */ 217 static void zstd_recv_cleanup(MultiFDRecvParams *p) 218 { 219 struct zstd_data *z = p->data; 220 221 ZSTD_freeDStream(z->zds); 222 z->zds = NULL; 223 g_free(z->zbuff); 224 z->zbuff = NULL; 225 g_free(p->data); 226 p->data = NULL; 227 } 228 229 /** 230 * zstd_recv_pages: read the data from the channel into actual pages 231 * 232 * Read the compressed buffer, and uncompress it into the actual 233 * pages. 234 * 235 * Returns 0 for success or -1 for error 236 * 237 * @p: Params for the channel that we are using 238 * @errp: pointer to an error 239 */ 240 static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp) 241 { 242 uint32_t in_size = p->next_packet_size; 243 uint32_t out_size = 0; 244 uint32_t expected_size = p->normal_num * p->page_size; 245 uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK; 246 struct zstd_data *z = p->data; 247 int ret; 248 int i; 249 250 if (flags != MULTIFD_FLAG_ZSTD) { 251 error_setg(errp, "multifd %u: flags received %x flags expected %x", 252 p->id, flags, MULTIFD_FLAG_ZSTD); 253 return -1; 254 } 255 ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp); 256 257 if (ret != 0) { 258 return ret; 259 } 260 261 z->in.src = z->zbuff; 262 z->in.size = in_size; 263 z->in.pos = 0; 264 265 for (i = 0; i < p->normal_num; i++) { 266 z->out.dst = p->host + p->normal[i]; 267 z->out.size = p->page_size; 268 z->out.pos = 0; 269 270 /* 271 * Welcome to decompressStream semantics 272 * 273 * We need to loop while: 274 * - return is > 0 275 * - there is input available 276 * - we haven't put out a full page 277 */ 278 do { 279 ret = ZSTD_decompressStream(z->zds, &z->out, &z->in); 280 } while (ret > 0 && (z->in.size - z->in.pos > 0) 281 && (z->out.pos < p->page_size)); 282 if (ret > 0 && (z->out.pos < p->page_size)) { 283 error_setg(errp, "multifd %u: decompressStream buffer too small", 284 p->id); 285 return -1; 286 } 287 if (ZSTD_isError(ret)) { 288 error_setg(errp, "multifd %u: decompressStream returned %s", 289 p->id, ZSTD_getErrorName(ret)); 290 return ret; 291 } 292 out_size += z->out.pos; 293 } 294 if (out_size != expected_size) { 295 error_setg(errp, "multifd %u: packet size received %u size expected %u", 296 p->id, out_size, expected_size); 297 return -1; 298 } 299 return 0; 300 } 301 302 static MultiFDMethods multifd_zstd_ops = { 303 .send_setup = zstd_send_setup, 304 .send_cleanup = zstd_send_cleanup, 305 .send_prepare = zstd_send_prepare, 306 .recv_setup = zstd_recv_setup, 307 .recv_cleanup = zstd_recv_cleanup, 308 .recv_pages = zstd_recv_pages 309 }; 310 311 static void multifd_zstd_register(void) 312 { 313 multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops); 314 } 315 316 migration_init(multifd_zstd_register); 317