migration/multifd-zstd.c

   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 "multifd.h"
  22
  23 struct zstd_data {
  24     /* stream for compression */
  25     ZSTD_CStream *zcs;
  26     /* stream for decompression */
  27     ZSTD_DStream *zds;
  28     /* buffers */
  29     ZSTD_inBuffer in;
  30     ZSTD_outBuffer out;
  31     /* compressed buffer */
  32     uint8_t *zbuff;
  33     /* size of compressed buffer */
  34     uint32_t zbuff_len;
  35 };
  36
  37 /* Multifd zstd compression */
  38
  39 /**
  40  * zstd_send_setup: setup send side
  41  *
  42  * Setup each channel with zstd compression.
  43  *
  44  * Returns 0 for success or -1 for error
  45  *
  46  * @p: Params for the channel that we are using
  47  * @errp: pointer to an error
  48  */
  49 static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
  50 {
  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     /* To be safe, we reserve twice the size of the packet */
  71     z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
  72     z->zbuff = g_try_malloc(z->zbuff_len);
  73     if (!z->zbuff) {
  74         ZSTD_freeCStream(z->zcs);
  75         g_free(z);
  76         error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
  77         return -1;
  78     }
  79     return 0;
  80 }
  81
  82 /**
  83  * zstd_send_cleanup: cleanup send side
  84  *
  85  * Close the channel and return memory.
  86  *
  87  * @p: Params for the channel that we are using
  88  * @errp: pointer to an error
  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  * @errp: pointer to an error
 112  */
 113 static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)
 114 {
 115     struct zstd_data *z = p->data;
 116     size_t page_size = qemu_target_page_size();
 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->pages->num; i++) {
 125         ZSTD_EndDirective flush = ZSTD_e_continue;
 126
 127         if (i == p->pages->num - 1) {
 128             flush = ZSTD_e_flush;
 129         }
 130         z->in.src = p->pages->block->host + p->pages->offset[i];
 131         z->in.size = 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 %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     struct zstd_data *z = g_new0(struct zstd_data, 1);
 195     int ret;
 196
 197     p->data = z;
 198     z->zds = ZSTD_createDStream();
 199     if (!z->zds) {
 200         g_free(z);
 201         error_setg(errp, "multifd %d: zstd createDStream failed", p->id);
 202         return -1;
 203     }
 204
 205     ret = ZSTD_initDStream(z->zds);
 206     if (ZSTD_isError(ret)) {
 207         ZSTD_freeDStream(z->zds);
 208         g_free(z);
 209         error_setg(errp, "multifd %d: initDStream failed with error %s",
 210                    p->id, ZSTD_getErrorName(ret));
 211         return -1;
 212     }
 213
 214     /* To be safe, we reserve twice the size of the packet */
 215     z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
 216     z->zbuff = g_try_malloc(z->zbuff_len);
 217     if (!z->zbuff) {
 218         ZSTD_freeDStream(z->zds);
 219         g_free(z);
 220         error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
 221         return -1;
 222     }
 223     return 0;
 224 }
 225
 226 /**
 227  * zstd_recv_cleanup: setup receive side
 228  *
 229  * For no compression this function does nothing.
 230  *
 231  * @p: Params for the channel that we are using
 232  */
 233 static void zstd_recv_cleanup(MultiFDRecvParams *p)
 234 {
 235     struct zstd_data *z = p->data;
 236
 237     ZSTD_freeDStream(z->zds);
 238     z->zds = NULL;
 239     g_free(z->zbuff);
 240     z->zbuff = NULL;
 241     g_free(p->data);
 242     p->data = NULL;
 243 }
 244
 245 /**
 246  * zstd_recv_pages: read the data from the channel into actual pages
 247  *
 248  * Read the compressed buffer, and uncompress it into the actual
 249  * pages.
 250  *
 251  * Returns 0 for success or -1 for error
 252  *
 253  * @p: Params for the channel that we are using
 254  * @errp: pointer to an error
 255  */
 256 static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp)
 257 {
 258     uint32_t in_size = p->next_packet_size;
 259     uint32_t out_size = 0;
 260     size_t page_size = qemu_target_page_size();
 261     uint32_t expected_size = p->pages->num * page_size;
 262     uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
 263     struct zstd_data *z = p->data;
 264     int ret;
 265     int i;
 266
 267     if (flags != MULTIFD_FLAG_ZSTD) {
 268         error_setg(errp, "multifd %d: flags received %x flags expected %x",
 269                    p->id, flags, MULTIFD_FLAG_ZSTD);
 270         return -1;
 271     }
 272     ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp);
 273
 274     if (ret != 0) {
 275         return ret;
 276     }
 277
 278     z->in.src = z->zbuff;
 279     z->in.size = in_size;
 280     z->in.pos = 0;
 281
 282     for (i = 0; i < p->pages->num; i++) {
 283         z->out.dst = p->pages->block->host + p->pages->offset[i];
 284         z->out.size = page_size;
 285         z->out.pos = 0;
 286
 287         /*
 288          * Welcome to decompressStream semantics
 289          *
 290          * We need to loop while:
 291          * - return is > 0
 292          * - there is input available
 293          * - we haven't put out a full page
 294          */
 295         do {
 296             ret = ZSTD_decompressStream(z->zds, &z->out, &z->in);
 297         } while (ret > 0 && (z->in.size - z->in.pos > 0)
 298                          && (z->out.pos < page_size));
 299         if (ret > 0 && (z->out.pos < page_size)) {
 300             error_setg(errp, "multifd %d: decompressStream buffer too small",
 301                        p->id);
 302             return -1;
 303         }
 304         if (ZSTD_isError(ret)) {
 305             error_setg(errp, "multifd %d: decompressStream returned %s",
 306                        p->id, ZSTD_getErrorName(ret));
 307             return ret;
 308         }
 309         out_size += z->out.pos;
 310     }
 311     if (out_size != expected_size) {
 312         error_setg(errp, "multifd %d: packet size received %d size expected %d",
 313                    p->id, out_size, expected_size);
 314         return -1;
 315     }
 316     return 0;
 317 }
 318
 319 static MultiFDMethods multifd_zstd_ops = {
 320     .send_setup = zstd_send_setup,
 321     .send_cleanup = zstd_send_cleanup,
 322     .send_prepare = zstd_send_prepare,
 323     .send_write = zstd_send_write,
 324     .recv_setup = zstd_recv_setup,
 325     .recv_cleanup = zstd_recv_cleanup,
 326     .recv_pages = zstd_recv_pages
 327 };
 328
 329 static void multifd_zstd_register(void)
 330 {
 331     multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops);
 332 }
 333
 334 migration_init(multifd_zstd_register);