migration/multifd-zstd.c - qemu - Git at Google

 /*
  * 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/ramblock.h"
 #include "exec/target_page.h"
 #include "qapi/error.h"
 #include "migration.h"
 #include "trace.h"
 #include "options.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)
 {
     struct zstd_data *z = g_new0(struct zstd_data, 1);
     int res;

     p->compress_data = z;
     z->zcs = ZSTD_createCStream();
     if (!z->zcs) {
         g_free(z);
         error_setg(errp, "multifd %u: 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 %u: initCStream failed with error %s",
                    p->id, ZSTD_getErrorName(res));
         return -1;
     }
     /* This is the maximum size of the compressed buffer */
     z->zbuff_len = ZSTD_compressBound(MULTIFD_PACKET_SIZE);
     z->zbuff = g_try_malloc(z->zbuff_len);
     if (!z->zbuff) {
         ZSTD_freeCStream(z->zcs);
         g_free(z);
         error_setg(errp, "multifd %u: 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
  * @errp: pointer to an error
  */
 static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp)
 {
     struct zstd_data *z = p->compress_data;

     ZSTD_freeCStream(z->zcs);
     z->zcs = NULL;
     g_free(z->zbuff);
     z->zbuff = NULL;
     g_free(p->compress_data);
     p->compress_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
  * @errp: pointer to an error
  */
 static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)
 {
     MultiFDPages_t *pages = p->pages;
     struct zstd_data *z = p->compress_data;
     int ret;
     uint32_t i;

     if (!multifd_send_prepare_common(p)) {
         goto out;
     }

     z->out.dst = z->zbuff;
     z->out.size = z->zbuff_len;
     z->out.pos = 0;

     for (i = 0; i < pages->normal_num; i++) {
         ZSTD_EndDirective flush = ZSTD_e_continue;

         if (i == pages->normal_num - 1) {
             flush = ZSTD_e_flush;
         }
         z->in.src = p->pages->block->host + pages->offset[i];
         z->in.size = p->page_size;
         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 %u: compressStream buffer too small",
                        p->id);
             return -1;
         }
         if (ZSTD_isError(ret)) {
             error_setg(errp, "multifd %u: compressStream error %s",
                        p->id, ZSTD_getErrorName(ret));
             return -1;
         }
     }
     p->iov[p->iovs_num].iov_base = z->zbuff;
     p->iov[p->iovs_num].iov_len = z->out.pos;
     p->iovs_num++;
     p->next_packet_size = z->out.pos;

 out:
     p->flags |= MULTIFD_FLAG_ZSTD;
     multifd_send_fill_packet(p);
     return 0;
 }

 /**
  * 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)
 {
     struct zstd_data *z = g_new0(struct zstd_data, 1);
     int ret;

     p->compress_data = z;
     z->zds = ZSTD_createDStream();
     if (!z->zds) {
         g_free(z);
         error_setg(errp, "multifd %u: 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 %u: initDStream failed with error %s",
                    p->id, ZSTD_getErrorName(ret));
         return -1;
     }

     /* To be safe, we reserve twice the size of the packet */
     z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
     z->zbuff = g_try_malloc(z->zbuff_len);
     if (!z->zbuff) {
         ZSTD_freeDStream(z->zds);
         g_free(z);
         error_setg(errp, "multifd %u: 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->compress_data;

     ZSTD_freeDStream(z->zds);
     z->zds = NULL;
     g_free(z->zbuff);
     z->zbuff = NULL;
     g_free(p->compress_data);
     p->compress_data = NULL;
 }

 /**
  * zstd_recv: 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
  * @errp: pointer to an error
  */
 static int zstd_recv(MultiFDRecvParams *p, Error **errp)
 {
     uint32_t in_size = p->next_packet_size;
     uint32_t out_size = 0;
     uint32_t expected_size = p->normal_num * p->page_size;
     uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
     struct zstd_data *z = p->compress_data;
     int ret;
     int i;

     if (flags != MULTIFD_FLAG_ZSTD) {
         error_setg(errp, "multifd %u: flags received %x flags expected %x",
                    p->id, flags, MULTIFD_FLAG_ZSTD);
         return -1;
     }

     multifd_recv_zero_page_process(p);

     if (!p->normal_num) {
         assert(in_size == 0);
         return 0;
     }

     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 < p->normal_num; i++) {
         z->out.dst = p->host + p->normal[i];
         z->out.size = p->page_size;
         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 < p->page_size));
         if (ret > 0 && (z->out.pos < p->page_size)) {
             error_setg(errp, "multifd %u: decompressStream buffer too small",
                        p->id);
             return -1;
         }
         if (ZSTD_isError(ret)) {
             error_setg(errp, "multifd %u: decompressStream returned %s",
                        p->id, ZSTD_getErrorName(ret));
             return ret;
         }
         out_size += z->out.pos;
     }
     if (out_size != expected_size) {
         error_setg(errp, "multifd %u: packet size received %u size expected %u",
                    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,
     .recv_setup = zstd_recv_setup,
     .recv_cleanup = zstd_recv_cleanup,
     .recv = zstd_recv
 };

 static void multifd_zstd_register(void)
 {
     multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops);
 }

 migration_init(multifd_zstd_register);
	/*
	* 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/ramblock.h"
	#include "exec/target_page.h"
	#include "qapi/error.h"
	#include "migration.h"
	#include "trace.h"
	#include "options.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)
	{
	struct zstd_data *z = g_new0(struct zstd_data, 1);
	int res;

	p->compress_data = z;
	z->zcs = ZSTD_createCStream();
	if (!z->zcs) {
	g_free(z);
	error_setg(errp, "multifd %u: 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 %u: initCStream failed with error %s",
	p->id, ZSTD_getErrorName(res));
	return -1;
	}
	/* This is the maximum size of the compressed buffer */
	z->zbuff_len = ZSTD_compressBound(MULTIFD_PACKET_SIZE);
	z->zbuff = g_try_malloc(z->zbuff_len);
	if (!z->zbuff) {
	ZSTD_freeCStream(z->zcs);
	g_free(z);
	error_setg(errp, "multifd %u: 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
	* @errp: pointer to an error
	*/
	static void zstd_send_cleanup(MultiFDSendParams p, Error *errp)
	{
	struct zstd_data *z = p->compress_data;

	ZSTD_freeCStream(z->zcs);
	z->zcs = NULL;
	g_free(z->zbuff);
	z->zbuff = NULL;
	g_free(p->compress_data);
	p->compress_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
	* @errp: pointer to an error
	*/
	static int zstd_send_prepare(MultiFDSendParams p, Error *errp)
	{
	MultiFDPages_t *pages = p->pages;
	struct zstd_data *z = p->compress_data;
	int ret;
	uint32_t i;

	if (!multifd_send_prepare_common(p)) {
	goto out;
	}

	z->out.dst = z->zbuff;
	z->out.size = z->zbuff_len;
	z->out.pos = 0;

	for (i = 0; i < pages->normal_num; i++) {
	ZSTD_EndDirective flush = ZSTD_e_continue;

	if (i == pages->normal_num - 1) {
	flush = ZSTD_e_flush;
	}
	z->in.src = p->pages->block->host + pages->offset[i];
	z->in.size = p->page_size;
	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 %u: compressStream buffer too small",
	p->id);
	return -1;
	}
	if (ZSTD_isError(ret)) {
	error_setg(errp, "multifd %u: compressStream error %s",
	p->id, ZSTD_getErrorName(ret));
	return -1;
	}
	}
	p->iov[p->iovs_num].iov_base = z->zbuff;
	p->iov[p->iovs_num].iov_len = z->out.pos;
	p->iovs_num++;
	p->next_packet_size = z->out.pos;

	out:
	p->flags \|= MULTIFD_FLAG_ZSTD;
	multifd_send_fill_packet(p);
	return 0;
	}

	/**
	* 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)
	{
	struct zstd_data *z = g_new0(struct zstd_data, 1);
	int ret;

	p->compress_data = z;
	z->zds = ZSTD_createDStream();
	if (!z->zds) {
	g_free(z);
	error_setg(errp, "multifd %u: 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 %u: initDStream failed with error %s",
	p->id, ZSTD_getErrorName(ret));
	return -1;
	}

	/* To be safe, we reserve twice the size of the packet */
	z->zbuff_len = MULTIFD_PACKET_SIZE * 2;
	z->zbuff = g_try_malloc(z->zbuff_len);
	if (!z->zbuff) {
	ZSTD_freeDStream(z->zds);
	g_free(z);
	error_setg(errp, "multifd %u: 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->compress_data;

	ZSTD_freeDStream(z->zds);
	z->zds = NULL;
	g_free(z->zbuff);
	z->zbuff = NULL;
	g_free(p->compress_data);
	p->compress_data = NULL;
	}

	/**
	* zstd_recv: 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
	* @errp: pointer to an error
	*/
	static int zstd_recv(MultiFDRecvParams p, Error *errp)
	{
	uint32_t in_size = p->next_packet_size;
	uint32_t out_size = 0;
	uint32_t expected_size = p->normal_num * p->page_size;
	uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
	struct zstd_data *z = p->compress_data;
	int ret;
	int i;

	if (flags != MULTIFD_FLAG_ZSTD) {
	error_setg(errp, "multifd %u: flags received %x flags expected %x",
	p->id, flags, MULTIFD_FLAG_ZSTD);
	return -1;
	}

	multifd_recv_zero_page_process(p);

	if (!p->normal_num) {
	assert(in_size == 0);
	return 0;
	}

	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 < p->normal_num; i++) {
	z->out.dst = p->host + p->normal[i];
	z->out.size = p->page_size;
	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 < p->page_size));
	if (ret > 0 && (z->out.pos < p->page_size)) {
	error_setg(errp, "multifd %u: decompressStream buffer too small",
	p->id);
	return -1;
	}
	if (ZSTD_isError(ret)) {
	error_setg(errp, "multifd %u: decompressStream returned %s",
	p->id, ZSTD_getErrorName(ret));
	return ret;
	}
	out_size += z->out.pos;
	}
	if (out_size != expected_size) {
	error_setg(errp, "multifd %u: packet size received %u size expected %u",
	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,
	.recv_setup = zstd_recv_setup,
	.recv_cleanup = zstd_recv_cleanup,
	.recv = zstd_recv
	};

	static void multifd_zstd_register(void)
	{
	multifd_register_ops(MULTIFD_COMPRESSION_ZSTD, &multifd_zstd_ops);
	}

	migration_init(multifd_zstd_register);