arch_init.c 38.2 KB
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/*
 * QEMU System Emulator
 *
 * Copyright (c) 2003-2008 Fabrice Bellard
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include <stdint.h>
#include <stdarg.h>
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#include <stdlib.h>
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#ifndef _WIN32
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#include <sys/types.h>
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#include <sys/mman.h>
#endif
#include "config.h"
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#include "monitor/monitor.h"
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#include "sysemu/sysemu.h"
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#include "qemu/bitops.h"
#include "qemu/bitmap.h"
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#include "sysemu/arch_init.h"
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#include "audio/audio.h"
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#include "hw/i386/pc.h"
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#include "hw/pci/pci.h"
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#include "hw/audio/audio.h"
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#include "sysemu/kvm.h"
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#include "migration/migration.h"
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#include "hw/i386/smbios.h"
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#include "exec/address-spaces.h"
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#include "hw/audio/pcspk.h"
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#include "migration/page_cache.h"
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#include "qemu/config-file.h"
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#include "qemu/error-report.h"
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#include "qmp-commands.h"
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#include "trace.h"
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#include "exec/cpu-all.h"
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#include "exec/ram_addr.h"
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#include "hw/acpi/acpi.h"
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#include "qemu/host-utils.h"
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#ifdef DEBUG_ARCH_INIT
#define DPRINTF(fmt, ...) \
    do { fprintf(stdout, "arch_init: " fmt, ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
    do { } while (0)
#endif

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#ifdef TARGET_SPARC
int graphic_width = 1024;
int graphic_height = 768;
int graphic_depth = 8;
#else
int graphic_width = 800;
int graphic_height = 600;
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int graphic_depth = 32;
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#endif


#if defined(TARGET_ALPHA)
#define QEMU_ARCH QEMU_ARCH_ALPHA
#elif defined(TARGET_ARM)
#define QEMU_ARCH QEMU_ARCH_ARM
#elif defined(TARGET_CRIS)
#define QEMU_ARCH QEMU_ARCH_CRIS
#elif defined(TARGET_I386)
#define QEMU_ARCH QEMU_ARCH_I386
#elif defined(TARGET_M68K)
#define QEMU_ARCH QEMU_ARCH_M68K
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#elif defined(TARGET_LM32)
#define QEMU_ARCH QEMU_ARCH_LM32
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#elif defined(TARGET_MICROBLAZE)
#define QEMU_ARCH QEMU_ARCH_MICROBLAZE
#elif defined(TARGET_MIPS)
#define QEMU_ARCH QEMU_ARCH_MIPS
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#elif defined(TARGET_MOXIE)
#define QEMU_ARCH QEMU_ARCH_MOXIE
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#elif defined(TARGET_OPENRISC)
#define QEMU_ARCH QEMU_ARCH_OPENRISC
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#elif defined(TARGET_PPC)
#define QEMU_ARCH QEMU_ARCH_PPC
#elif defined(TARGET_S390X)
#define QEMU_ARCH QEMU_ARCH_S390X
#elif defined(TARGET_SH4)
#define QEMU_ARCH QEMU_ARCH_SH4
#elif defined(TARGET_SPARC)
#define QEMU_ARCH QEMU_ARCH_SPARC
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#elif defined(TARGET_XTENSA)
#define QEMU_ARCH QEMU_ARCH_XTENSA
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#elif defined(TARGET_UNICORE32)
#define QEMU_ARCH QEMU_ARCH_UNICORE32
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#endif

const uint32_t arch_type = QEMU_ARCH;
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static bool mig_throttle_on;
static int dirty_rate_high_cnt;
static void check_guest_throttling(void);
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static uint64_t bitmap_sync_count;

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/***********************************************************/
/* ram save/restore */

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#define RAM_SAVE_FLAG_FULL     0x01 /* Obsolete, not used anymore */
#define RAM_SAVE_FLAG_COMPRESS 0x02
#define RAM_SAVE_FLAG_MEM_SIZE 0x04
#define RAM_SAVE_FLAG_PAGE     0x08
#define RAM_SAVE_FLAG_EOS      0x10
#define RAM_SAVE_FLAG_CONTINUE 0x20
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#define RAM_SAVE_FLAG_XBZRLE   0x40
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/* 0x80 is reserved in migration.h start with 0x100 next */
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static struct defconfig_file {
    const char *filename;
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    /* Indicates it is an user config file (disabled by -no-user-config) */
    bool userconfig;
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} default_config_files[] = {
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    { CONFIG_QEMU_CONFDIR "/qemu.conf",                   true },
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    { CONFIG_QEMU_CONFDIR "/target-" TARGET_NAME ".conf", true },
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    { NULL }, /* end of list */
};

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static const uint8_t ZERO_TARGET_PAGE[TARGET_PAGE_SIZE];
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int qemu_read_default_config_files(bool userconfig)
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{
    int ret;
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    struct defconfig_file *f;
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    for (f = default_config_files; f->filename; f++) {
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        if (!userconfig && f->userconfig) {
            continue;
        }
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        ret = qemu_read_config_file(f->filename);
        if (ret < 0 && ret != -ENOENT) {
            return ret;
        }
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    }
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    return 0;
}

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static inline bool is_zero_range(uint8_t *p, uint64_t size)
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{
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    return buffer_find_nonzero_offset(p, size) == size;
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}

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/* struct contains XBZRLE cache and a static page
   used by the compression */
static struct {
    /* buffer used for XBZRLE encoding */
    uint8_t *encoded_buf;
    /* buffer for storing page content */
    uint8_t *current_buf;
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    /* Cache for XBZRLE, Protected by lock. */
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    PageCache *cache;
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    QemuMutex lock;
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} XBZRLE;

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/* buffer used for XBZRLE decoding */
static uint8_t *xbzrle_decoded_buf;
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static void XBZRLE_cache_lock(void)
{
    if (migrate_use_xbzrle())
        qemu_mutex_lock(&XBZRLE.lock);
}

static void XBZRLE_cache_unlock(void)
{
    if (migrate_use_xbzrle())
        qemu_mutex_unlock(&XBZRLE.lock);
}

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/*
 * called from qmp_migrate_set_cache_size in main thread, possibly while
 * a migration is in progress.
 * A running migration maybe using the cache and might finish during this
 * call, hence changes to the cache are protected by XBZRLE.lock().
 */
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int64_t xbzrle_cache_resize(int64_t new_size)
{
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    PageCache *new_cache;
    int64_t ret;
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    if (new_size < TARGET_PAGE_SIZE) {
        return -1;
    }

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    XBZRLE_cache_lock();

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    if (XBZRLE.cache != NULL) {
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        if (pow2floor(new_size) == migrate_xbzrle_cache_size()) {
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            goto out_new_size;
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        }
        new_cache = cache_init(new_size / TARGET_PAGE_SIZE,
                                        TARGET_PAGE_SIZE);
        if (!new_cache) {
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            error_report("Error creating cache");
            ret = -1;
            goto out;
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        }

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        cache_fini(XBZRLE.cache);
        XBZRLE.cache = new_cache;
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    }
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out_new_size:
    ret = pow2floor(new_size);
out:
    XBZRLE_cache_unlock();
    return ret;
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}

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/* accounting for migration statistics */
typedef struct AccountingInfo {
    uint64_t dup_pages;
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    uint64_t skipped_pages;
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    uint64_t norm_pages;
    uint64_t iterations;
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    uint64_t xbzrle_bytes;
    uint64_t xbzrle_pages;
    uint64_t xbzrle_cache_miss;
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    double xbzrle_cache_miss_rate;
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    uint64_t xbzrle_overflows;
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} AccountingInfo;

static AccountingInfo acct_info;

static void acct_clear(void)
{
    memset(&acct_info, 0, sizeof(acct_info));
}

uint64_t dup_mig_bytes_transferred(void)
{
    return acct_info.dup_pages * TARGET_PAGE_SIZE;
}

uint64_t dup_mig_pages_transferred(void)
{
    return acct_info.dup_pages;
}

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uint64_t skipped_mig_bytes_transferred(void)
{
    return acct_info.skipped_pages * TARGET_PAGE_SIZE;
}

uint64_t skipped_mig_pages_transferred(void)
{
    return acct_info.skipped_pages;
}

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uint64_t norm_mig_bytes_transferred(void)
{
    return acct_info.norm_pages * TARGET_PAGE_SIZE;
}

uint64_t norm_mig_pages_transferred(void)
{
    return acct_info.norm_pages;
}

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uint64_t xbzrle_mig_bytes_transferred(void)
{
    return acct_info.xbzrle_bytes;
}

uint64_t xbzrle_mig_pages_transferred(void)
{
    return acct_info.xbzrle_pages;
}

uint64_t xbzrle_mig_pages_cache_miss(void)
{
    return acct_info.xbzrle_cache_miss;
}

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double xbzrle_mig_cache_miss_rate(void)
{
    return acct_info.xbzrle_cache_miss_rate;
}

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uint64_t xbzrle_mig_pages_overflow(void)
{
    return acct_info.xbzrle_overflows;
}

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static size_t save_block_hdr(QEMUFile *f, RAMBlock *block, ram_addr_t offset,
                             int cont, int flag)
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{
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    size_t size;

    qemu_put_be64(f, offset | cont | flag);
    size = 8;
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    if (!cont) {
        qemu_put_byte(f, strlen(block->idstr));
        qemu_put_buffer(f, (uint8_t *)block->idstr,
                        strlen(block->idstr));
        size += 1 + strlen(block->idstr);
    }
    return size;
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}

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/* This is the last block that we have visited serching for dirty pages
 */
static RAMBlock *last_seen_block;
/* This is the last block from where we have sent data */
static RAMBlock *last_sent_block;
static ram_addr_t last_offset;
static unsigned long *migration_bitmap;
static uint64_t migration_dirty_pages;
static uint32_t last_version;
static bool ram_bulk_stage;

/* Update the xbzrle cache to reflect a page that's been sent as all 0.
 * The important thing is that a stale (not-yet-0'd) page be replaced
 * by the new data.
 * As a bonus, if the page wasn't in the cache it gets added so that
 * when a small write is made into the 0'd page it gets XBZRLE sent
 */
static void xbzrle_cache_zero_page(ram_addr_t current_addr)
{
    if (ram_bulk_stage || !migrate_use_xbzrle()) {
        return;
    }

    /* We don't care if this fails to allocate a new cache page
     * as long as it updated an old one */
    cache_insert(XBZRLE.cache, current_addr, ZERO_TARGET_PAGE);
}

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#define ENCODING_FLAG_XBZRLE 0x1

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static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data,
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                            ram_addr_t current_addr, RAMBlock *block,
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                            ram_addr_t offset, int cont, bool last_stage)
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{
    int encoded_len = 0, bytes_sent = -1;
    uint8_t *prev_cached_page;

    if (!cache_is_cached(XBZRLE.cache, current_addr)) {
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        acct_info.xbzrle_cache_miss++;
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        if (!last_stage) {
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            if (cache_insert(XBZRLE.cache, current_addr, *current_data) == -1) {
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                return -1;
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            } else {
                /* update *current_data when the page has been
                   inserted into cache */
                *current_data = get_cached_data(XBZRLE.cache, current_addr);
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            }
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        }
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        return -1;
    }

    prev_cached_page = get_cached_data(XBZRLE.cache, current_addr);

    /* save current buffer into memory */
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    memcpy(XBZRLE.current_buf, *current_data, TARGET_PAGE_SIZE);
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    /* XBZRLE encoding (if there is no overflow) */
    encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf,
                                       TARGET_PAGE_SIZE, XBZRLE.encoded_buf,
                                       TARGET_PAGE_SIZE);
    if (encoded_len == 0) {
        DPRINTF("Skipping unmodified page\n");
        return 0;
    } else if (encoded_len == -1) {
        DPRINTF("Overflow\n");
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        acct_info.xbzrle_overflows++;
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        /* update data in the cache */
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        if (!last_stage) {
            memcpy(prev_cached_page, *current_data, TARGET_PAGE_SIZE);
            *current_data = prev_cached_page;
        }
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        return -1;
    }

    /* we need to update the data in the cache, in order to get the same data */
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    if (!last_stage) {
        memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
    }
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    /* Send XBZRLE based compressed page */
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    bytes_sent = save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_XBZRLE);
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    qemu_put_byte(f, ENCODING_FLAG_XBZRLE);
    qemu_put_be16(f, encoded_len);
    qemu_put_buffer(f, XBZRLE.encoded_buf, encoded_len);
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    bytes_sent += encoded_len + 1 + 2;
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    acct_info.xbzrle_pages++;
    acct_info.xbzrle_bytes += bytes_sent;
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    return bytes_sent;
}

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static inline
ram_addr_t migration_bitmap_find_and_reset_dirty(MemoryRegion *mr,
                                                 ram_addr_t start)
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{
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    unsigned long base = mr->ram_addr >> TARGET_PAGE_BITS;
    unsigned long nr = base + (start >> TARGET_PAGE_BITS);
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    uint64_t mr_size = TARGET_PAGE_ALIGN(memory_region_size(mr));
    unsigned long size = base + (mr_size >> TARGET_PAGE_BITS);
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    unsigned long next;

    if (ram_bulk_stage && nr > base) {
        next = nr + 1;
    } else {
        next = find_next_bit(migration_bitmap, size, nr);
    }
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    if (next < size) {
        clear_bit(next, migration_bitmap);
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        migration_dirty_pages--;
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    }
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    return (next - base) << TARGET_PAGE_BITS;
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}

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static inline bool migration_bitmap_set_dirty(ram_addr_t addr)
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{
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    bool ret;
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    int nr = addr >> TARGET_PAGE_BITS;
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    ret = test_and_set_bit(nr, migration_bitmap);

    if (!ret) {
        migration_dirty_pages++;
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    }
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    return ret;
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}

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static void migration_bitmap_sync_range(ram_addr_t start, ram_addr_t length)
{
    ram_addr_t addr;
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    unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);

    /* start address is aligned at the start of a word? */
    if (((page * BITS_PER_LONG) << TARGET_PAGE_BITS) == start) {
        int k;
        int nr = BITS_TO_LONGS(length >> TARGET_PAGE_BITS);
        unsigned long *src = ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION];

        for (k = page; k < page + nr; k++) {
            if (src[k]) {
                unsigned long new_dirty;
                new_dirty = ~migration_bitmap[k];
                migration_bitmap[k] |= src[k];
                new_dirty &= src[k];
                migration_dirty_pages += ctpopl(new_dirty);
                src[k] = 0;
            }
        }
    } else {
        for (addr = 0; addr < length; addr += TARGET_PAGE_SIZE) {
            if (cpu_physical_memory_get_dirty(start + addr,
                                              TARGET_PAGE_SIZE,
                                              DIRTY_MEMORY_MIGRATION)) {
                cpu_physical_memory_reset_dirty(start + addr,
                                                TARGET_PAGE_SIZE,
                                                DIRTY_MEMORY_MIGRATION);
                migration_bitmap_set_dirty(start + addr);
            }
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        }
    }
}


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/* Needs iothread lock! */

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static void migration_bitmap_sync(void)
{
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    RAMBlock *block;
    uint64_t num_dirty_pages_init = migration_dirty_pages;
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    MigrationState *s = migrate_get_current();
    static int64_t start_time;
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    static int64_t bytes_xfer_prev;
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    static int64_t num_dirty_pages_period;
    int64_t end_time;
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    int64_t bytes_xfer_now;
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    static uint64_t xbzrle_cache_miss_prev;
    static uint64_t iterations_prev;
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    bitmap_sync_count++;

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    if (!bytes_xfer_prev) {
        bytes_xfer_prev = ram_bytes_transferred();
    }
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    if (!start_time) {
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        start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
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    }
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    trace_migration_bitmap_sync_start();
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    address_space_sync_dirty_bitmap(&address_space_memory);
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    QTAILQ_FOREACH(block, &ram_list.blocks, next) {
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        migration_bitmap_sync_range(block->mr->ram_addr, block->length);
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    }
    trace_migration_bitmap_sync_end(migration_dirty_pages
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                                    - num_dirty_pages_init);
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    num_dirty_pages_period += migration_dirty_pages - num_dirty_pages_init;
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    end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
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    /* more than 1 second = 1000 millisecons */
    if (end_time > start_time + 1000) {
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        if (migrate_auto_converge()) {
            /* The following detection logic can be refined later. For now:
               Check to see if the dirtied bytes is 50% more than the approx.
               amount of bytes that just got transferred since the last time we
               were in this routine. If that happens >N times (for now N==4)
               we turn on the throttle down logic */
            bytes_xfer_now = ram_bytes_transferred();
            if (s->dirty_pages_rate &&
               (num_dirty_pages_period * TARGET_PAGE_SIZE >
                   (bytes_xfer_now - bytes_xfer_prev)/2) &&
               (dirty_rate_high_cnt++ > 4)) {
                    trace_migration_throttle();
                    mig_throttle_on = true;
                    dirty_rate_high_cnt = 0;
             }
             bytes_xfer_prev = bytes_xfer_now;
        } else {
             mig_throttle_on = false;
        }
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        if (migrate_use_xbzrle()) {
            if (iterations_prev != 0) {
                acct_info.xbzrle_cache_miss_rate =
                   (double)(acct_info.xbzrle_cache_miss -
                            xbzrle_cache_miss_prev) /
                   (acct_info.iterations - iterations_prev);
            }
            iterations_prev = acct_info.iterations;
            xbzrle_cache_miss_prev = acct_info.xbzrle_cache_miss;
        }
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        s->dirty_pages_rate = num_dirty_pages_period * 1000
            / (end_time - start_time);
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        s->dirty_bytes_rate = s->dirty_pages_rate * TARGET_PAGE_SIZE;
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        start_time = end_time;
        num_dirty_pages_period = 0;
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        s->dirty_sync_count = bitmap_sync_count;
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    }
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}

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/*
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 * ram_save_page: Send the given page to the stream
 *
 * Returns: Number of bytes written.
 */
static int ram_save_page(QEMUFile *f, RAMBlock* block, ram_addr_t offset,
                         bool last_stage)
{
    int bytes_sent;
    int cont;
    ram_addr_t current_addr;
    MemoryRegion *mr = block->mr;
    uint8_t *p;
    int ret;
    bool send_async = true;

    cont = (block == last_sent_block) ? RAM_SAVE_FLAG_CONTINUE : 0;

    p = memory_region_get_ram_ptr(mr) + offset;

    /* In doubt sent page as normal */
    bytes_sent = -1;
    ret = ram_control_save_page(f, block->offset,
                           offset, TARGET_PAGE_SIZE, &bytes_sent);

    XBZRLE_cache_lock();

    current_addr = block->offset + offset;
    if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
        if (ret != RAM_SAVE_CONTROL_DELAYED) {
            if (bytes_sent > 0) {
                acct_info.norm_pages++;
            } else if (bytes_sent == 0) {
                acct_info.dup_pages++;
            }
        }
    } else if (is_zero_range(p, TARGET_PAGE_SIZE)) {
        acct_info.dup_pages++;
        bytes_sent = save_block_hdr(f, block, offset, cont,
                                    RAM_SAVE_FLAG_COMPRESS);
        qemu_put_byte(f, 0);
        bytes_sent++;
        /* Must let xbzrle know, otherwise a previous (now 0'd) cached
         * page would be stale
         */
        xbzrle_cache_zero_page(current_addr);
    } else if (!ram_bulk_stage && migrate_use_xbzrle()) {
        bytes_sent = save_xbzrle_page(f, &p, current_addr, block,
                                      offset, cont, last_stage);
        if (!last_stage) {
            /* Can't send this cached data async, since the cache page
             * might get updated before it gets to the wire
             */
            send_async = false;
        }
    }

    /* XBZRLE overflow or normal page */
    if (bytes_sent == -1) {
        bytes_sent = save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_PAGE);
        if (send_async) {
            qemu_put_buffer_async(f, p, TARGET_PAGE_SIZE);
        } else {
            qemu_put_buffer(f, p, TARGET_PAGE_SIZE);
        }
        bytes_sent += TARGET_PAGE_SIZE;
        acct_info.norm_pages++;
    }

    XBZRLE_cache_unlock();

    return bytes_sent;
}

/*
 * ram_find_and_save_block: Finds a page to send and sends it to f
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 *
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 * Returns:  The number of bytes written.
 *           0 means no dirty pages
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 */

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static int ram_find_and_save_block(QEMUFile *f, bool last_stage)
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{
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    RAMBlock *block = last_seen_block;
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    ram_addr_t offset = last_offset;
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    bool complete_round = false;
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    int bytes_sent = 0;
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    MemoryRegion *mr;
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    if (!block)
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        block = QTAILQ_FIRST(&ram_list.blocks);
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    while (true) {
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        mr = block->mr;
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        offset = migration_bitmap_find_and_reset_dirty(mr, offset);
        if (complete_round && block == last_seen_block &&
            offset >= last_offset) {
            break;
        }
        if (offset >= block->length) {
            offset = 0;
            block = QTAILQ_NEXT(block, next);
            if (!block) {
                block = QTAILQ_FIRST(&ram_list.blocks);
                complete_round = true;
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                ram_bulk_stage = false;
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            }
        } else {
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            bytes_sent = ram_save_page(f, block, offset, last_stage);
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            /* if page is unmodified, continue to the next */
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            if (bytes_sent > 0) {
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                last_sent_block = block;
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                break;
            }
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        }
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    }
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    last_seen_block = block;
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    last_offset = offset;
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    return bytes_sent;
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}

static uint64_t bytes_transferred;

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void acct_update_position(QEMUFile *f, size_t size, bool zero)
{
    uint64_t pages = size / TARGET_PAGE_SIZE;
    if (zero) {
        acct_info.dup_pages += pages;
    } else {
        acct_info.norm_pages += pages;
        bytes_transferred += size;
        qemu_update_position(f, size);
    }
}

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static ram_addr_t ram_save_remaining(void)
{
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    return migration_dirty_pages;
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}

uint64_t ram_bytes_remaining(void)
{
    return ram_save_remaining() * TARGET_PAGE_SIZE;
}

uint64_t ram_bytes_transferred(void)
{
    return bytes_transferred;
}

uint64_t ram_bytes_total(void)
{
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    RAMBlock *block;
    uint64_t total = 0;

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    QTAILQ_FOREACH(block, &ram_list.blocks, next)
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        total += block->length;

    return total;
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}

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void free_xbzrle_decoded_buf(void)
{
    g_free(xbzrle_decoded_buf);
    xbzrle_decoded_buf = NULL;
}

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static void migration_end(void)
{
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    if (migration_bitmap) {
        memory_global_dirty_log_stop();
        g_free(migration_bitmap);
        migration_bitmap = NULL;
    }
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    XBZRLE_cache_lock();
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    if (XBZRLE.cache) {
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        cache_fini(XBZRLE.cache);
        g_free(XBZRLE.encoded_buf);
        g_free(XBZRLE.current_buf);
        XBZRLE.cache = NULL;
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        XBZRLE.encoded_buf = NULL;
        XBZRLE.current_buf = NULL;
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    }
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    XBZRLE_cache_unlock();
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}

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static void ram_migration_cancel(void *opaque)
{
    migration_end();
}

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static void reset_ram_globals(void)
{
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    last_seen_block = NULL;
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    last_sent_block = NULL;
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    last_offset = 0;
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    last_version = ram_list.version;
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    ram_bulk_stage = true;
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}

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#define MAX_WAIT 50 /* ms, half buffered_file limit */

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static int ram_save_setup(QEMUFile *f, void *opaque)
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{
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    RAMBlock *block;
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    int64_t ram_bitmap_pages; /* Size of bitmap in pages, including gaps */
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    mig_throttle_on = false;
    dirty_rate_high_cnt = 0;
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    bitmap_sync_count = 0;
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    if (migrate_use_xbzrle()) {
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        XBZRLE_cache_lock();
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        XBZRLE.cache = cache_init(migrate_xbzrle_cache_size() /
                                  TARGET_PAGE_SIZE,
                                  TARGET_PAGE_SIZE);
        if (!XBZRLE.cache) {
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            XBZRLE_cache_unlock();
            error_report("Error creating cache");
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            return -1;
        }
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        XBZRLE_cache_unlock();
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        /* We prefer not to abort if there is no memory */
        XBZRLE.encoded_buf = g_try_malloc0(TARGET_PAGE_SIZE);
        if (!XBZRLE.encoded_buf) {
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            error_report("Error allocating encoded_buf");
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            return -1;
        }

        XBZRLE.current_buf = g_try_malloc(TARGET_PAGE_SIZE);
        if (!XBZRLE.current_buf) {
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            error_report("Error allocating current_buf");
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            g_free(XBZRLE.encoded_buf);
            XBZRLE.encoded_buf = NULL;
            return -1;
        }

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        acct_clear();
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    }

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    qemu_mutex_lock_iothread();
    qemu_mutex_lock_ramlist();
    bytes_transferred = 0;
    reset_ram_globals();

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    ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
    migration_bitmap = bitmap_new(ram_bitmap_pages);
    bitmap_set(migration_bitmap, 0, ram_bitmap_pages);

    /*
     * Count the total number of pages used by ram blocks not including any
     * gaps due to alignment or unplugs.
     */
    migration_dirty_pages = 0;
    QTAILQ_FOREACH(block, &ram_list.blocks, next) {
        uint64_t block_pages;

        block_pages = block->length >> TARGET_PAGE_BITS;
        migration_dirty_pages += block_pages;
    }

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    memory_global_dirty_log_start();
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    migration_bitmap_sync();
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    qemu_mutex_unlock_iothread();
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    qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
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    QTAILQ_FOREACH(block, &ram_list.blocks, next) {
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        qemu_put_byte(f, strlen(block->idstr));
        qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
        qemu_put_be64(f, block->length);
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    }

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    qemu_mutex_unlock_ramlist();
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    ram_control_before_iterate(f, RAM_CONTROL_SETUP);
    ram_control_after_iterate(f, RAM_CONTROL_SETUP);

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    qemu_put_be64(f, RAM_SAVE_FLAG_EOS);

    return 0;
}

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static int ram_save_iterate(QEMUFile *f, void *opaque)
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{
    int ret;
    int i;
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    int64_t t0;
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    int total_sent = 0;
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    qemu_mutex_lock_ramlist();

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    if (ram_list.version != last_version) {
        reset_ram_globals();
    }

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    ram_control_before_iterate(f, RAM_CONTROL_ROUND);

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    t0 = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
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    i = 0;
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    while ((ret = qemu_file_rate_limit(f)) == 0) {
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        int bytes_sent;
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        bytes_sent = ram_find_and_save_block(f, false);
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        /* no more blocks to sent */
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        if (bytes_sent == 0) {
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            break;
        }
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        total_sent += bytes_sent;
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        acct_info.iterations++;
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        check_guest_throttling();
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        /* we want to check in the 1st loop, just in case it was the 1st time
           and we had to sync the dirty bitmap.
           qemu_get_clock_ns() is a bit expensive, so we only check each some
           iterations
        */
        if ((i & 63) == 0) {
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            uint64_t t1 = (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - t0) / 1000000;
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            if (t1 > MAX_WAIT) {
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                DPRINTF("big wait: %" PRIu64 " milliseconds, %d iterations\n",
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                        t1, i);
                break;
            }
        }
        i++;
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    }

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    qemu_mutex_unlock_ramlist();

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    /*
     * Must occur before EOS (or any QEMUFile operation)
     * because of RDMA protocol.
     */
    ram_control_after_iterate(f, RAM_CONTROL_ROUND);

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    bytes_transferred += total_sent;

    /*
     * Do not count these 8 bytes into total_sent, so that we can
     * return 0 if no page had been dirtied.
     */
    qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
    bytes_transferred += 8;

    ret = qemu_file_get_error(f);
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    if (ret < 0) {
        return ret;
    }

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    return total_sent;
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}

static int ram_save_complete(QEMUFile *f, void *opaque)
{
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    qemu_mutex_lock_ramlist();
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    migration_bitmap_sync();
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    ram_control_before_iterate(f, RAM_CONTROL_FINISH);

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    /* try transferring iterative blocks of memory */
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    /* flush all remaining blocks regardless of rate limiting */
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    while (true) {
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        int bytes_sent;

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        bytes_sent = ram_find_and_save_block(f, true);
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        /* no more blocks to sent */
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        if (bytes_sent == 0) {
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            break;
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        }
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        bytes_transferred += bytes_sent;
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    }
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    ram_control_after_iterate(f, RAM_CONTROL_FINISH);
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    migration_end();
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    qemu_mutex_unlock_ramlist();
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    qemu_put_be64(f, RAM_SAVE_FLAG_EOS);

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    return 0;
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}

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static uint64_t ram_save_pending(QEMUFile *f, void *opaque, uint64_t max_size)
{
    uint64_t remaining_size;

    remaining_size = ram_save_remaining() * TARGET_PAGE_SIZE;

    if (remaining_size < max_size) {
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        qemu_mutex_lock_iothread();
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        migration_bitmap_sync();
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        qemu_mutex_unlock_iothread();
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        remaining_size = ram_save_remaining() * TARGET_PAGE_SIZE;
    }
    return remaining_size;
}

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static int load_xbzrle(QEMUFile *f, ram_addr_t addr, void *host)
{
    unsigned int xh_len;
    int xh_flags;

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    if (!xbzrle_decoded_buf) {
        xbzrle_decoded_buf = g_malloc(TARGET_PAGE_SIZE);
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    }

    /* extract RLE header */
    xh_flags = qemu_get_byte(f);
    xh_len = qemu_get_be16(f);

    if (xh_flags != ENCODING_FLAG_XBZRLE) {
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        error_report("Failed to load XBZRLE page - wrong compression!");
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        return -1;
    }

    if (xh_len > TARGET_PAGE_SIZE) {
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        error_report("Failed to load XBZRLE page - len overflow!");
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        return -1;
    }
    /* load data and decode */
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    qemu_get_buffer(f, xbzrle_decoded_buf, xh_len);
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    /* decode RLE */
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    if (xbzrle_decode_buffer(xbzrle_decoded_buf, xh_len, host,
                             TARGET_PAGE_SIZE) == -1) {
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        error_report("Failed to load XBZRLE page - decode error!");
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        return -1;
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    }

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    return 0;
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}

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static inline void *host_from_stream_offset(QEMUFile *f,
                                            ram_addr_t offset,
                                            int flags)
{
    static RAMBlock *block = NULL;
    char id[256];
    uint8_t len;

    if (flags & RAM_SAVE_FLAG_CONTINUE) {
        if (!block) {
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            error_report("Ack, bad migration stream!");
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            return NULL;
        }

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        return memory_region_get_ram_ptr(block->mr) + offset;
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    }

    len = qemu_get_byte(f);
    qemu_get_buffer(f, (uint8_t *)id, len);
    id[len] = 0;

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    QTAILQ_FOREACH(block, &ram_list.blocks, next) {
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        if (!strncmp(id, block->idstr, sizeof(id)))
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            return memory_region_get_ram_ptr(block->mr) + offset;
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    }

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    error_report("Can't find block %s!", id);
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    return NULL;
}

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/*
 * If a page (or a whole RDMA chunk) has been
 * determined to be zero, then zap it.
 */
void ram_handle_compressed(void *host, uint8_t ch, uint64_t size)
{
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    if (ch != 0 || !is_zero_range(host, size)) {
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        memset(host, ch, size);
    }
}

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static int ram_load(QEMUFile *f, void *opaque, int version_id)
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{
    ram_addr_t addr;
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    int flags, ret = 0;
    static uint64_t seq_iter;

    seq_iter++;
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    if (version_id != 4) {
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        ret = -EINVAL;
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    }

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    while (!ret) {
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        addr = qemu_get_be64(f);

        flags = addr & ~TARGET_PAGE_MASK;
        addr &= TARGET_PAGE_MASK;

        if (flags & RAM_SAVE_FLAG_MEM_SIZE) {
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            /* Synchronize RAM block list */
            char id[256];
            ram_addr_t length;
            ram_addr_t total_ram_bytes = addr;

            while (total_ram_bytes) {
                RAMBlock *block;
                uint8_t len;

                len = qemu_get_byte(f);
                qemu_get_buffer(f, (uint8_t *)id, len);
                id[len] = 0;
                length = qemu_get_be64(f);

                QTAILQ_FOREACH(block, &ram_list.blocks, next) {
                    if (!strncmp(id, block->idstr, sizeof(id))) {
                        if (block->length != length) {
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                            error_report("Length mismatch: %s: 0x" RAM_ADDR_FMT
                                         " in != 0x" RAM_ADDR_FMT, id, length,
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                                         block->length);
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                            ret =  -EINVAL;
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                        }
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                        break;
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                    }