migration/multifd-zlib.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 <zlib.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 zlib_data {
  24     /* stream for compression */
  25     z_stream zs;
  26     /* compressed buffer */
  27     uint8_t *zbuff;
  28     /* size of compressed buffer */
  29     uint32_t zbuff_len;
  30 };
  31
  32 /* Multifd zlib compression */
  33
  34 /**
  35  * zlib_send_setup: setup send side
  36  *
  37  * Setup each channel with zlib compression.
  38  *
  39  * Returns 0 for success or -1 for error
  40  *
  41  * @p: Params for the channel that we are using
  42  * @errp: pointer to an error
  43  */
  44 static int zlib_send_setup(MultiFDSendParams *p, Error **errp)
  45 {
  46     struct zlib_data *z = g_malloc0(sizeof(struct zlib_data));
  47     z_stream *zs = &z->zs;
  48
  49     zs->zalloc = Z_NULL;
  50     zs->zfree = Z_NULL;
  51     zs->opaque = Z_NULL;
  52     if (deflateInit(zs, migrate_multifd_zlib_level()) != Z_OK) {
  53         g_free(z);
  54         error_setg(errp, "multifd %d: deflate init failed", p->id);
  55         return -1;
  56     }
  57     /* To be safe, we reserve twice the size of the packet */
  58     z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
  59     z->zbuff = g_try_malloc(z->zbuff_len);
  60     if (!z->zbuff) {
  61         deflateEnd(&z->zs);
  62         g_free(z);
  63         error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
  64         return -1;
  65     }
  66     p->data = z;
  67     return 0;
  68 }
  69
  70 /**
  71  * zlib_send_cleanup: cleanup send side
  72  *
  73  * Close the channel and return memory.
  74  *
  75  * @p: Params for the channel that we are using
  76  * @errp: pointer to an error
  77  */
  78 static void zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
  79 {
  80     struct zlib_data *z = p->data;
  81
  82     deflateEnd(&z->zs);
  83     g_free(z->zbuff);
  84     z->zbuff = NULL;
  85     g_free(p->data);
  86     p->data = NULL;
  87 }
  88
  89 /**
  90  * zlib_send_prepare: prepare date to be able to send
  91  *
  92  * Create a compressed buffer with all the pages that we are going to
  93  * send.
  94  *
  95  * Returns 0 for success or -1 for error
  96  *
  97  * @p: Params for the channel that we are using
  98  * @errp: pointer to an error
  99  */
 100 static int zlib_send_prepare(MultiFDSendParams *p, Error **errp)
 101 {
 102     struct zlib_data *z = p->data;
 103     size_t page_size = qemu_target_page_size();
 104     z_stream *zs = &z->zs;
 105     uint32_t out_size = 0;
 106     int ret;
 107     uint32_t i;
 108
 109     for (i = 0; i < p->pages->num; i++) {
 110         uint32_t available = z->zbuff_len - out_size;
 111         int flush = Z_NO_FLUSH;
 112
 113         if (i == p->pages->num - 1) {
 114             flush = Z_SYNC_FLUSH;
 115         }
 116
 117         zs->avail_in = page_size;
 118         zs->next_in = p->pages->block->host + p->pages->offset[i];
 119
 120         zs->avail_out = available;
 121         zs->next_out = z->zbuff + out_size;
 122
 123         /*
 124          * Welcome to deflate semantics
 125          *
 126          * We need to loop while:
 127          * - return is Z_OK
 128          * - there are stuff to be compressed
 129          * - there are output space free
 130          */
 131         do {
 132             ret = deflate(zs, flush);
 133         } while (ret == Z_OK && zs->avail_in && zs->avail_out);
 134         if (ret == Z_OK && zs->avail_in) {
 135             error_setg(errp, "multifd %d: deflate failed to compress all input",
 136                        p->id);
 137             return -1;
 138         }
 139         if (ret != Z_OK) {
 140             error_setg(errp, "multifd %d: deflate returned %d instead of Z_OK",
 141                        p->id, ret);
 142             return -1;
 143         }
 144         out_size += available - zs->avail_out;
 145     }
 146     p->next_packet_size = out_size;
 147     p->flags |= MULTIFD_FLAG_ZLIB;
 148
 149     return 0;
 150 }
 151
 152 /**
 153  * zlib_send_write: do the actual write of the data
 154  *
 155  * Do the actual write of the comprresed buffer.
 156  *
 157  * Returns 0 for success or -1 for error
 158  *
 159  * @p: Params for the channel that we are using
 160  * @used: number of pages used
 161  * @errp: pointer to an error
 162  */
 163 static int zlib_send_write(MultiFDSendParams *p, uint32_t used, Error **errp)
 164 {
 165     struct zlib_data *z = p->data;
 166
 167     return qio_channel_write_all(p->c, (void *)z->zbuff, p->next_packet_size,
 168                                  errp);
 169 }
 170
 171 /**
 172  * zlib_recv_setup: setup receive side
 173  *
 174  * Create the compressed channel and buffer.
 175  *
 176  * Returns 0 for success or -1 for error
 177  *
 178  * @p: Params for the channel that we are using
 179  * @errp: pointer to an error
 180  */
 181 static int zlib_recv_setup(MultiFDRecvParams *p, Error **errp)
 182 {
 183     struct zlib_data *z = g_malloc0(sizeof(struct zlib_data));
 184     z_stream *zs = &z->zs;
 185
 186     p->data = z;
 187     zs->zalloc = Z_NULL;
 188     zs->zfree = Z_NULL;
 189     zs->opaque = Z_NULL;
 190     zs->avail_in = 0;
 191     zs->next_in = Z_NULL;
 192     if (inflateInit(zs) != Z_OK) {
 193         error_setg(errp, "multifd %d: inflate init failed", p->id);
 194         return -1;
 195     }
 196     /* To be safe, we reserve twice the size of the packet */
 197     z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
 198     z->zbuff = g_try_malloc(z->zbuff_len);
 199     if (!z->zbuff) {
 200         inflateEnd(zs);
 201         error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
 202         return -1;
 203     }
 204     return 0;
 205 }
 206
 207 /**
 208  * zlib_recv_cleanup: setup receive side
 209  *
 210  * For no compression this function does nothing.
 211  *
 212  * @p: Params for the channel that we are using
 213  */
 214 static void zlib_recv_cleanup(MultiFDRecvParams *p)
 215 {
 216     struct zlib_data *z = p->data;
 217
 218     inflateEnd(&z->zs);
 219     g_free(z->zbuff);
 220     z->zbuff = NULL;
 221     g_free(p->data);
 222     p->data = NULL;
 223 }
 224
 225 /**
 226  * zlib_recv_pages: read the data from the channel into actual pages
 227  *
 228  * Read the compressed buffer, and uncompress it into the actual
 229  * pages.
 230  *
 231  * Returns 0 for success or -1 for error
 232  *
 233  * @p: Params for the channel that we are using
 234  * @errp: pointer to an error
 235  */
 236 static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
 237 {
 238     struct zlib_data *z = p->data;
 239     size_t page_size = qemu_target_page_size();
 240     z_stream *zs = &z->zs;
 241     uint32_t in_size = p->next_packet_size;
 242     /* we measure the change of total_out */
 243     uint32_t out_size = zs->total_out;
 244     uint32_t expected_size = p->pages->num * qemu_target_page_size();
 245     uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
 246     int ret;
 247     int i;
 248
 249     if (flags != MULTIFD_FLAG_ZLIB) {
 250         error_setg(errp, "multifd %d: flags received %x flags expected %x",
 251                    p->id, flags, MULTIFD_FLAG_ZLIB);
 252         return -1;
 253     }
 254     ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp);
 255
 256     if (ret != 0) {
 257         return ret;
 258     }
 259
 260     zs->avail_in = in_size;
 261     zs->next_in = z->zbuff;
 262
 263     for (i = 0; i < p->pages->num; i++) {
 264         int flush = Z_NO_FLUSH;
 265         unsigned long start = zs->total_out;
 266
 267         if (i == p->pages->num - 1) {
 268             flush = Z_SYNC_FLUSH;
 269         }
 270
 271         zs->avail_out = page_size;
 272         zs->next_out = p->pages->block->host + p->pages->offset[i];
 273
 274         /*
 275          * Welcome to inflate semantics
 276          *
 277          * We need to loop while:
 278          * - return is Z_OK
 279          * - there are input available
 280          * - we haven't completed a full page
 281          */
 282         do {
 283             ret = inflate(zs, flush);
 284         } while (ret == Z_OK && zs->avail_in
 285                              && (zs->total_out - start) < page_size);
 286         if (ret == Z_OK && (zs->total_out - start) < page_size) {
 287             error_setg(errp, "multifd %d: inflate generated too few output",
 288                        p->id);
 289             return -1;
 290         }
 291         if (ret != Z_OK) {
 292             error_setg(errp, "multifd %d: inflate returned %d instead of Z_OK",
 293                        p->id, ret);
 294             return -1;
 295         }
 296     }
 297     out_size = zs->total_out - out_size;
 298     if (out_size != expected_size) {
 299         error_setg(errp, "multifd %d: packet size received %d size expected %d",
 300                    p->id, out_size, expected_size);
 301         return -1;
 302     }
 303     return 0;
 304 }
 305
 306 static MultiFDMethods multifd_zlib_ops = {
 307     .send_setup = zlib_send_setup,
 308     .send_cleanup = zlib_send_cleanup,
 309     .send_prepare = zlib_send_prepare,
 310     .send_write = zlib_send_write,
 311     .recv_setup = zlib_recv_setup,
 312     .recv_cleanup = zlib_recv_cleanup,
 313     .recv_pages = zlib_recv_pages
 314 };
 315
 316 static void multifd_zlib_register(void)
 317 {
 318     multifd_register_ops(MULTIFD_COMPRESSION_ZLIB, &multifd_zlib_ops);
 319 }
 320
 321 migration_init(multifd_zlib_register);