/*
* Multifd zlib compression implementation
*
* Copyright (c) 2020 Red Hat Inc
*
* Authors:
* Juan Quintela <quintela@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include <zstd.h>
#include "qemu/rcu.h"
#include "exec/target_page.h"
#include "qapi/error.h"
#include "migration.h"
#include "trace.h"
#include "multifd.h"
struct zstd_data {
/* stream for compression */
ZSTD_CStream *zcs;
/* stream for decompression */
ZSTD_DStream *zds;
/* buffers */
ZSTD_inBuffer in;
ZSTD_outBuffer out;
/* compressed buffer */
uint8_t *zbuff;
/* size of compressed buffer */
uint32_t zbuff_len;
};
/* Multifd zstd compression */
/**
* zstd_send_setup: setup send side
*
* Setup each channel with zstd compression.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
{
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
struct zstd_data *z = g_new0(struct zstd_data, 1);
int res;
p->data = z;
z->zcs = ZSTD_createCStream();
if (!z->zcs) {
g_free(z);
error_setg(errp, "multifd %d: zstd createCStream failed", p->id);
return -1;
}
res = ZSTD_initCStream(z->zcs, migrate_multifd_zstd_level());
if (ZSTD_isError(res)) {
ZSTD_freeCStream(z->zcs);
g_free(z);
error_setg(errp, "multifd %d: initCStream failed with error %s",
p->id, ZSTD_getErrorName(res));
return -1;
}
/* We will never have more than page_count pages */
z->zbuff_len = page_count * qemu_target_page_size();
z->zbuff_len *= 2;
z->zbuff = g_try_malloc(z->zbuff_len);
if (!z->zbuff) {
ZSTD_freeCStream(z->zcs);
g_free(z);
error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
return -1;
}
return 0;
}
/**
* zstd_send_cleanup: cleanup send side
*
* Close the channel and return memory.
*
* @p: Params for the channel that we are using
*/
static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp)
{
struct zstd_data *z = p->data;
ZSTD_freeCStream(z->zcs);
z->zcs = NULL;
g_free(z->zbuff);
z->zbuff = NULL;
g_free(p->data);
p->data = NULL;
}
/**
* zstd_send_prepare: prepare date to be able to send
*
* Create a compressed buffer with all the pages that we are going to
* send.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @used: number of pages used
*/
static int zstd_send_prepare(MultiFDSendParams *p, uint32_t used, Error **errp)
{
struct iovec *iov = p->pages->iov;
struct zstd_data *z = p->data;
int ret;
uint32_t i;
z->out.dst = z->zbuff;
z->out.size = z->zbuff_len;
z->out.pos = 0;
for (i = 0; i < used; i++) {
ZSTD_EndDirective flush = ZSTD_e_continue;
if (i == used - 1) {
flush = ZSTD_e_flush;
}
z->in.src = iov[i].iov_base;
z->in.size = iov[i].iov_len;
z->in.pos = 0;
/*
* Welcome to compressStream2 semantics
*
* We need to loop while:
* - return is > 0
* - there is input available
* - there is output space free
*/
do {
ret = ZSTD_compressStream2(z->zcs, &z->out, &z->in, flush);
} while (ret > 0 && (z->in.size - z->in.pos > 0)
&& (z->out.size - z->out.pos > 0));
if (ret > 0 && (z->in.size - z->in.pos > 0)) {
error_setg(errp, "multifd %d: compressStream buffer too small",
p->id);
return -1;
}
if (ZSTD_isError(ret)) {
error_setg(errp, "multifd %d: compressStream error %s",
p->id, ZSTD_getErrorName(ret));
return -1;
}
}
p->next_packet_size = z->out.pos;
p->flags |= MULTIFD_FLAG_ZSTD;
return 0;
}
/**
* zstd_send_write: do the actual write of the data
*
* Do the actual write of the comprresed buffer.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @used: number of pages used
* @errp: pointer to an error
*/
static int zstd_send_write(MultiFDSendParams *p, uint32_t used, Error **errp)
{
struct zstd_data *z = p->data;
return qio_channel_write_all(p->c, (void *)z->zbuff, p->next_packet_size,
errp);
}
/**
* zstd_recv_setup: setup receive side
*
* Create the compressed channel and buffer.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp)
{
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
struct zstd_data *z = g_new0(struct zstd_data, 1);
int ret;
p->data = z;
z->zds = ZSTD_createDStream();
if (!z->zds) {
g_free(z);
error_setg(errp, "multifd %d: zstd createDStream failed", p->id);
return -1;
}
ret = ZSTD_initDStream(z->zds);
if (ZSTD_isError(ret)) {
ZSTD_freeDStream(z->zds);
g_free(z);
error_setg(errp, "multifd %d: initDStream failed with error %s",
p->id, ZSTD_getErrorName(ret));
return -1;
}
/* We will never have more than page_count pages */
z->zbuff_len = page_count * qemu_target_page_size();
/* We know compression "could" use more space */
z->zbuff_len *= 2;
z->zbuff = g_try_malloc(z->zbuff_len);
if (!z->zbuff) {
ZSTD_freeDStream(z->zds);
g_free(z);
error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
return -1;
}
return 0;
}
/**
* zstd_recv_cleanup: setup receive side
*
* For no compression this function does nothing.
*
* @p: Params for the channel that we are using
*/
static void zstd_recv_cleanup(MultiFDRecvParams *p)
{
struct zstd_data *z = p->data;
ZSTD_freeDStream(z->zds);
z->zds = NULL;
g_free(z->zbuff);
z->zbuff = NULL;
g_free(p->data);
p->data = NULL;
}
/**
* zstd_recv_pages: read the data from the channel into actual pages
*
* Read the compressed buffer, and uncompress it into the actual
* pages.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @used: number of pages used
* @errp: pointer to an error
*/
static int zstd_recv_pages(MultiFDRecvParams *p, uint32_t used, Error **errp)
{
uint32_t in_size = p->next_packet_size;
uint32_t out_size = 0;
uint32_t expected_size = used * qemu_target_page_size();
uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
struct zstd_data *z = p->data;
int ret;
int i;
if (flags != MULTIFD_FLAG_ZSTD) {
error_setg(errp, "multifd %d: flags received %x flags expected %x",
p->id, flags, MULTIFD_FLAG_ZSTD);
return -1;
}
ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp);
if (ret != 0) {
return ret;
}
z->in.src = z->zbuff;
z->in.size = in_size;
z->in.pos = 0;
for (i = 0; i < used; i++) {
struct iovec *iov = &p->pages->iov[i];
z->out.dst = iov->iov_base;
z->out.size = iov->iov_len;
z->out.pos = 0;
/*
* Welcome to decompressStream semantics
*
* We need to loop while:
* - return is > 0
* - there is input available
* - we haven't put out a full page
*/
do {
ret = ZSTD_decompressStream(z->zds, &z->out, &z->in);
} while (ret > 0 && (z->in.size - z->in.pos > 0)
&& (z->out.pos < iov->iov_len));
if (ret > 0 && (z->out.pos < iov->iov_len)) {
error_setg(errp, "multifd %d: decompressStream buffer too small",
p->id);
return -1;
}
if (ZSTD_isError(ret)) {
error_setg(errp, "multifd %d: decompressStream returned %s",
p->id, ZSTD_getErrorName(ret));
return ret;
}
out_size += z->out.pos;
}
if (out_size != expected_size) {
error_setg(errp, "multifd %d: packet size received %d size expected %d",
p->id, out_size, expected_size);
return -1;
}
return 0;
}
static MultiFDMethods multifd_zstd_ops = {
.send_setup = zstd_send_setup,
.send_cleanup = zstd_send_cleanup,
.send_prepare = zstd_send_prepare,
.send_write = zstd_send_write,
.recv_setup = zstd_recv_setup,
.recv_cleanup = zstd_recv_cleanup,
.recv_pages = zstd_recv_pages
};
static void multifd_zstd_register(void)
{
multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops);
}
migration_init(multifd_zstd_register);
