/*
* 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 <zlib.h>
#include "qemu/rcu.h"
#include "exec/target_page.h"
#include "qapi/error.h"
#include "migration.h"
#include "trace.h"
#include "multifd.h"
struct zlib_data {
/* stream for compression */
z_stream zs;
/* compressed buffer */
uint8_t *zbuff;
/* size of compressed buffer */
uint32_t zbuff_len;
};
/* Multifd zlib compression */
/**
* zlib_send_setup: setup send side
*
* Setup each channel with zlib 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 zlib_send_setup(MultiFDSendParams *p, Error **errp)
{
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
struct zlib_data *z = g_malloc0(sizeof(struct zlib_data));
z_stream *zs = &z->zs;
zs->zalloc = Z_NULL;
zs->zfree = Z_NULL;
zs->opaque = Z_NULL;
if (deflateInit(zs, migrate_multifd_zlib_level()) != Z_OK) {
g_free(z);
error_setg(errp, "multifd %d: deflate init failed", p->id);
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) {
deflateEnd(&z->zs);
g_free(z);
error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
return -1;
}
p->data = z;
return 0;
}
/**
* zlib_send_cleanup: cleanup send side
*
* Close the channel and return memory.
*
* @p: Params for the channel that we are using
*/
static void zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
{
struct zlib_data *z = p->data;
deflateEnd(&z->zs);
g_free(z->zbuff);
z->zbuff = NULL;
g_free(p->data);
p->data = NULL;
}
/**
* zlib_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 zlib_send_prepare(MultiFDSendParams *p, uint32_t used, Error **errp)
{
struct iovec *iov = p->pages->iov;
struct zlib_data *z = p->data;
z_stream *zs = &z->zs;
uint32_t out_size = 0;
int ret;
uint32_t i;
for (i = 0; i < used; i++) {
uint32_t available = z->zbuff_len - out_size;
int flush = Z_NO_FLUSH;
if (i == used - 1) {
flush = Z_SYNC_FLUSH;
}
zs->avail_in = iov[i].iov_len;
zs->next_in = iov[i].iov_base;
zs->avail_out = available;
zs->next_out = z->zbuff + out_size;
/*
* Welcome to deflate semantics
*
* We need to loop while:
* - return is Z_OK
* - there are stuff to be compressed
* - there are output space free
*/
do {
ret = deflate(zs, flush);
} while (ret == Z_OK && zs->avail_in && zs->avail_out);
if (ret == Z_OK && zs->avail_in) {
error_setg(errp, "multifd %d: deflate failed to compress all input",
p->id);
return -1;
}
if (ret != Z_OK) {
error_setg(errp, "multifd %d: deflate returned %d instead of Z_OK",
p->id, ret);
return -1;
}
out_size += available - zs->avail_out;
}
p->next_packet_size = out_size;
p->flags |= MULTIFD_FLAG_ZLIB;
return 0;
}
/**
* zlib_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 zlib_send_write(MultiFDSendParams *p, uint32_t used, Error **errp)
{
struct zlib_data *z = p->data;
return qio_channel_write_all(p->c, (void *)z->zbuff, p->next_packet_size,
errp);
}
/**
* zlib_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 zlib_recv_setup(MultiFDRecvParams *p, Error **errp)
{
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
struct zlib_data *z = g_malloc0(sizeof(struct zlib_data));
z_stream *zs = &z->zs;
p->data = z;
zs->zalloc = Z_NULL;
zs->zfree = Z_NULL;
zs->opaque = Z_NULL;
zs->avail_in = 0;
zs->next_in = Z_NULL;
if (inflateInit(zs) != Z_OK) {
error_setg(errp, "multifd %d: inflate init failed", p->id);
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) {
inflateEnd(zs);
error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
return -1;
}
return 0;
}
/**
* zlib_recv_cleanup: setup receive side
*
* For no compression this function does nothing.
*
* @p: Params for the channel that we are using
*/
static void zlib_recv_cleanup(MultiFDRecvParams *p)
{
struct zlib_data *z = p->data;
inflateEnd(&z->zs);
g_free(z->zbuff);
z->zbuff = NULL;
g_free(p->data);
p->data = NULL;
}
/**
* zlib_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 zlib_recv_pages(MultiFDRecvParams *p, uint32_t used, Error **errp)
{
struct zlib_data *z = p->data;
z_stream *zs = &z->zs;
uint32_t in_size = p->next_packet_size;
/* we measure the change of total_out */
uint32_t out_size = zs->total_out;
uint32_t expected_size = used * qemu_target_page_size();
uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
int ret;
int i;
if (flags != MULTIFD_FLAG_ZLIB) {
error_setg(errp, "multifd %d: flags received %x flags expected %x",
p->id, flags, MULTIFD_FLAG_ZLIB);
return -1;
}
ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp);
if (ret != 0) {
return ret;
}
zs->avail_in = in_size;
zs->next_in = z->zbuff;
for (i = 0; i < used; i++) {
struct iovec *iov = &p->pages->iov[i];
int flush = Z_NO_FLUSH;
unsigned long start = zs->total_out;
if (i == used - 1) {
flush = Z_SYNC_FLUSH;
}
zs->avail_out = iov->iov_len;
zs->next_out = iov->iov_base;
/*
* Welcome to inflate semantics
*
* We need to loop while:
* - return is Z_OK
* - there are input available
* - we haven't completed a full page
*/
do {
ret = inflate(zs, flush);
} while (ret == Z_OK && zs->avail_in
&& (zs->total_out - start) < iov->iov_len);
if (ret == Z_OK && (zs->total_out - start) < iov->iov_len) {
error_setg(errp, "multifd %d: inflate generated too few output",
p->id);
return -1;
}
if (ret != Z_OK) {
error_setg(errp, "multifd %d: inflate returned %d instead of Z_OK",
p->id, ret);
return -1;
}
}
out_size = zs->total_out - out_size;
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_zlib_ops = {
.send_setup = zlib_send_setup,
.send_cleanup = zlib_send_cleanup,
.send_prepare = zlib_send_prepare,
.send_write = zlib_send_write,
.recv_setup = zlib_recv_setup,
.recv_cleanup = zlib_recv_cleanup,
.recv_pages = zlib_recv_pages
};
static void multifd_zlib_register(void)
{
multifd_register_ops(MULTIFD_COMPRESSION_ZLIB, &multifd_zlib_ops);
}
migration_init(multifd_zlib_register);
