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-rw-r--r--src/migration/ram.c2544
1 files changed, 2544 insertions, 0 deletions
diff --git a/src/migration/ram.c b/src/migration/ram.c
new file mode 100644
index 0000000..0490f00
--- /dev/null
+++ b/src/migration/ram.c
@@ -0,0 +1,2544 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2011-2015 Red Hat Inc
+ *
+ * Authors:
+ * Juan Quintela <quintela@redhat.com>
+ *
+ * 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 <zlib.h>
+#include "qemu/bitops.h"
+#include "qemu/bitmap.h"
+#include "qemu/timer.h"
+#include "qemu/main-loop.h"
+#include "migration/migration.h"
+#include "migration/postcopy-ram.h"
+#include "exec/address-spaces.h"
+#include "migration/page_cache.h"
+#include "qemu/error-report.h"
+#include "trace.h"
+#include "exec/ram_addr.h"
+#include "qemu/rcu_queue.h"
+
+#ifdef DEBUG_MIGRATION_RAM
+#define DPRINTF(fmt, ...) \
+ do { fprintf(stdout, "migration_ram: " fmt, ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) \
+ do { } while (0)
+#endif
+
+static int dirty_rate_high_cnt;
+
+static uint64_t bitmap_sync_count;
+
+/***********************************************************/
+/* ram save/restore */
+
+#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
+#define RAM_SAVE_FLAG_XBZRLE 0x40
+/* 0x80 is reserved in migration.h start with 0x100 next */
+#define RAM_SAVE_FLAG_COMPRESS_PAGE 0x100
+
+static const uint8_t ZERO_TARGET_PAGE[TARGET_PAGE_SIZE];
+
+static inline bool is_zero_range(uint8_t *p, uint64_t size)
+{
+ return buffer_find_nonzero_offset(p, size) == size;
+}
+
+/* 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;
+ /* Cache for XBZRLE, Protected by lock. */
+ PageCache *cache;
+ QemuMutex lock;
+} XBZRLE;
+
+/* buffer used for XBZRLE decoding */
+static uint8_t *xbzrle_decoded_buf;
+
+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);
+}
+
+/*
+ * 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().
+ */
+int64_t xbzrle_cache_resize(int64_t new_size)
+{
+ PageCache *new_cache;
+ int64_t ret;
+
+ if (new_size < TARGET_PAGE_SIZE) {
+ return -1;
+ }
+
+ XBZRLE_cache_lock();
+
+ if (XBZRLE.cache != NULL) {
+ if (pow2floor(new_size) == migrate_xbzrle_cache_size()) {
+ goto out_new_size;
+ }
+ new_cache = cache_init(new_size / TARGET_PAGE_SIZE,
+ TARGET_PAGE_SIZE);
+ if (!new_cache) {
+ error_report("Error creating cache");
+ ret = -1;
+ goto out;
+ }
+
+ cache_fini(XBZRLE.cache);
+ XBZRLE.cache = new_cache;
+ }
+
+out_new_size:
+ ret = pow2floor(new_size);
+out:
+ XBZRLE_cache_unlock();
+ return ret;
+}
+
+/* accounting for migration statistics */
+typedef struct AccountingInfo {
+ uint64_t dup_pages;
+ uint64_t skipped_pages;
+ uint64_t norm_pages;
+ uint64_t iterations;
+ uint64_t xbzrle_bytes;
+ uint64_t xbzrle_pages;
+ uint64_t xbzrle_cache_miss;
+ double xbzrle_cache_miss_rate;
+ uint64_t xbzrle_overflows;
+} 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;
+}
+
+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;
+}
+
+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;
+}
+
+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;
+}
+
+double xbzrle_mig_cache_miss_rate(void)
+{
+ return acct_info.xbzrle_cache_miss_rate;
+}
+
+uint64_t xbzrle_mig_pages_overflow(void)
+{
+ return acct_info.xbzrle_overflows;
+}
+
+/* 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 QemuMutex migration_bitmap_mutex;
+static uint64_t migration_dirty_pages;
+static uint32_t last_version;
+static bool ram_bulk_stage;
+
+/* used by the search for pages to send */
+struct PageSearchStatus {
+ /* Current block being searched */
+ RAMBlock *block;
+ /* Current offset to search from */
+ ram_addr_t offset;
+ /* Set once we wrap around */
+ bool complete_round;
+};
+typedef struct PageSearchStatus PageSearchStatus;
+
+static struct BitmapRcu {
+ struct rcu_head rcu;
+ /* Main migration bitmap */
+ unsigned long *bmap;
+ /* bitmap of pages that haven't been sent even once
+ * only maintained and used in postcopy at the moment
+ * where it's used to send the dirtymap at the start
+ * of the postcopy phase
+ */
+ unsigned long *unsentmap;
+} *migration_bitmap_rcu;
+
+struct CompressParam {
+ bool start;
+ bool done;
+ QEMUFile *file;
+ QemuMutex mutex;
+ QemuCond cond;
+ RAMBlock *block;
+ ram_addr_t offset;
+};
+typedef struct CompressParam CompressParam;
+
+struct DecompressParam {
+ bool start;
+ QemuMutex mutex;
+ QemuCond cond;
+ void *des;
+ uint8 *compbuf;
+ int len;
+};
+typedef struct DecompressParam DecompressParam;
+
+static CompressParam *comp_param;
+static QemuThread *compress_threads;
+/* comp_done_cond is used to wake up the migration thread when
+ * one of the compression threads has finished the compression.
+ * comp_done_lock is used to co-work with comp_done_cond.
+ */
+static QemuMutex *comp_done_lock;
+static QemuCond *comp_done_cond;
+/* The empty QEMUFileOps will be used by file in CompressParam */
+static const QEMUFileOps empty_ops = { };
+
+static bool compression_switch;
+static bool quit_comp_thread;
+static bool quit_decomp_thread;
+static DecompressParam *decomp_param;
+static QemuThread *decompress_threads;
+static uint8_t *compressed_data_buf;
+
+static int do_compress_ram_page(CompressParam *param);
+
+static void *do_data_compress(void *opaque)
+{
+ CompressParam *param = opaque;
+
+ while (!quit_comp_thread) {
+ qemu_mutex_lock(&param->mutex);
+ /* Re-check the quit_comp_thread in case of
+ * terminate_compression_threads is called just before
+ * qemu_mutex_lock(&param->mutex) and after
+ * while(!quit_comp_thread), re-check it here can make
+ * sure the compression thread terminate as expected.
+ */
+ while (!param->start && !quit_comp_thread) {
+ qemu_cond_wait(&param->cond, &param->mutex);
+ }
+ if (!quit_comp_thread) {
+ do_compress_ram_page(param);
+ }
+ param->start = false;
+ qemu_mutex_unlock(&param->mutex);
+
+ qemu_mutex_lock(comp_done_lock);
+ param->done = true;
+ qemu_cond_signal(comp_done_cond);
+ qemu_mutex_unlock(comp_done_lock);
+ }
+
+ return NULL;
+}
+
+static inline void terminate_compression_threads(void)
+{
+ int idx, thread_count;
+
+ thread_count = migrate_compress_threads();
+ quit_comp_thread = true;
+ for (idx = 0; idx < thread_count; idx++) {
+ qemu_mutex_lock(&comp_param[idx].mutex);
+ qemu_cond_signal(&comp_param[idx].cond);
+ qemu_mutex_unlock(&comp_param[idx].mutex);
+ }
+}
+
+void migrate_compress_threads_join(void)
+{
+ int i, thread_count;
+
+ if (!migrate_use_compression()) {
+ return;
+ }
+ terminate_compression_threads();
+ thread_count = migrate_compress_threads();
+ for (i = 0; i < thread_count; i++) {
+ qemu_thread_join(compress_threads + i);
+ qemu_fclose(comp_param[i].file);
+ qemu_mutex_destroy(&comp_param[i].mutex);
+ qemu_cond_destroy(&comp_param[i].cond);
+ }
+ qemu_mutex_destroy(comp_done_lock);
+ qemu_cond_destroy(comp_done_cond);
+ g_free(compress_threads);
+ g_free(comp_param);
+ g_free(comp_done_cond);
+ g_free(comp_done_lock);
+ compress_threads = NULL;
+ comp_param = NULL;
+ comp_done_cond = NULL;
+ comp_done_lock = NULL;
+}
+
+void migrate_compress_threads_create(void)
+{
+ int i, thread_count;
+
+ if (!migrate_use_compression()) {
+ return;
+ }
+ quit_comp_thread = false;
+ compression_switch = true;
+ thread_count = migrate_compress_threads();
+ compress_threads = g_new0(QemuThread, thread_count);
+ comp_param = g_new0(CompressParam, thread_count);
+ comp_done_cond = g_new0(QemuCond, 1);
+ comp_done_lock = g_new0(QemuMutex, 1);
+ qemu_cond_init(comp_done_cond);
+ qemu_mutex_init(comp_done_lock);
+ for (i = 0; i < thread_count; i++) {
+ /* com_param[i].file is just used as a dummy buffer to save data, set
+ * it's ops to empty.
+ */
+ comp_param[i].file = qemu_fopen_ops(NULL, &empty_ops);
+ comp_param[i].done = true;
+ qemu_mutex_init(&comp_param[i].mutex);
+ qemu_cond_init(&comp_param[i].cond);
+ qemu_thread_create(compress_threads + i, "compress",
+ do_data_compress, comp_param + i,
+ QEMU_THREAD_JOINABLE);
+ }
+}
+
+/**
+ * save_page_header: Write page header to wire
+ *
+ * If this is the 1st block, it also writes the block identification
+ *
+ * Returns: Number of bytes written
+ *
+ * @f: QEMUFile where to send the data
+ * @block: block that contains the page we want to send
+ * @offset: offset inside the block for the page
+ * in the lower bits, it contains flags
+ */
+static size_t save_page_header(QEMUFile *f, RAMBlock *block, ram_addr_t offset)
+{
+ size_t size, len;
+
+ qemu_put_be64(f, offset);
+ size = 8;
+
+ if (!(offset & RAM_SAVE_FLAG_CONTINUE)) {
+ len = strlen(block->idstr);
+ qemu_put_byte(f, len);
+ qemu_put_buffer(f, (uint8_t *)block->idstr, len);
+ size += 1 + len;
+ }
+ return size;
+}
+
+/* Reduce amount of guest cpu execution to hopefully slow down memory writes.
+ * If guest dirty memory rate is reduced below the rate at which we can
+ * transfer pages to the destination then we should be able to complete
+ * migration. Some workloads dirty memory way too fast and will not effectively
+ * converge, even with auto-converge.
+ */
+static void mig_throttle_guest_down(void)
+{
+ MigrationState *s = migrate_get_current();
+ uint64_t pct_initial =
+ s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INITIAL];
+ uint64_t pct_icrement =
+ s->parameters[MIGRATION_PARAMETER_X_CPU_THROTTLE_INCREMENT];
+
+ /* We have not started throttling yet. Let's start it. */
+ if (!cpu_throttle_active()) {
+ cpu_throttle_set(pct_initial);
+ } else {
+ /* Throttling already on, just increase the rate */
+ cpu_throttle_set(cpu_throttle_get_percentage() + pct_icrement);
+ }
+}
+
+/* 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,
+ bitmap_sync_count);
+}
+
+#define ENCODING_FLAG_XBZRLE 0x1
+
+/**
+ * save_xbzrle_page: compress and send current page
+ *
+ * Returns: 1 means that we wrote the page
+ * 0 means that page is identical to the one already sent
+ * -1 means that xbzrle would be longer than normal
+ *
+ * @f: QEMUFile where to send the data
+ * @current_data:
+ * @current_addr:
+ * @block: block that contains the page we want to send
+ * @offset: offset inside the block for the page
+ * @last_stage: if we are at the completion stage
+ * @bytes_transferred: increase it with the number of transferred bytes
+ */
+static int save_xbzrle_page(QEMUFile *f, uint8_t **current_data,
+ ram_addr_t current_addr, RAMBlock *block,
+ ram_addr_t offset, bool last_stage,
+ uint64_t *bytes_transferred)
+{
+ int encoded_len = 0, bytes_xbzrle;
+ uint8_t *prev_cached_page;
+
+ if (!cache_is_cached(XBZRLE.cache, current_addr, bitmap_sync_count)) {
+ acct_info.xbzrle_cache_miss++;
+ if (!last_stage) {
+ if (cache_insert(XBZRLE.cache, current_addr, *current_data,
+ bitmap_sync_count) == -1) {
+ return -1;
+ } else {
+ /* update *current_data when the page has been
+ inserted into cache */
+ *current_data = get_cached_data(XBZRLE.cache, current_addr);
+ }
+ }
+ return -1;
+ }
+
+ prev_cached_page = get_cached_data(XBZRLE.cache, current_addr);
+
+ /* save current buffer into memory */
+ memcpy(XBZRLE.current_buf, *current_data, TARGET_PAGE_SIZE);
+
+ /* 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");
+ acct_info.xbzrle_overflows++;
+ /* update data in the cache */
+ if (!last_stage) {
+ memcpy(prev_cached_page, *current_data, TARGET_PAGE_SIZE);
+ *current_data = prev_cached_page;
+ }
+ return -1;
+ }
+
+ /* we need to update the data in the cache, in order to get the same data */
+ if (!last_stage) {
+ memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
+ }
+
+ /* Send XBZRLE based compressed page */
+ bytes_xbzrle = save_page_header(f, block, offset | RAM_SAVE_FLAG_XBZRLE);
+ qemu_put_byte(f, ENCODING_FLAG_XBZRLE);
+ qemu_put_be16(f, encoded_len);
+ qemu_put_buffer(f, XBZRLE.encoded_buf, encoded_len);
+ bytes_xbzrle += encoded_len + 1 + 2;
+ acct_info.xbzrle_pages++;
+ acct_info.xbzrle_bytes += bytes_xbzrle;
+ *bytes_transferred += bytes_xbzrle;
+
+ return 1;
+}
+
+/* Called with rcu_read_lock() to protect migration_bitmap
+ * rb: The RAMBlock to search for dirty pages in
+ * start: Start address (typically so we can continue from previous page)
+ * ram_addr_abs: Pointer into which to store the address of the dirty page
+ * within the global ram_addr space
+ *
+ * Returns: byte offset within memory region of the start of a dirty page
+ */
+static inline
+ram_addr_t migration_bitmap_find_dirty(RAMBlock *rb,
+ ram_addr_t start,
+ ram_addr_t *ram_addr_abs)
+{
+ unsigned long base = rb->offset >> TARGET_PAGE_BITS;
+ unsigned long nr = base + (start >> TARGET_PAGE_BITS);
+ uint64_t rb_size = rb->used_length;
+ unsigned long size = base + (rb_size >> TARGET_PAGE_BITS);
+ unsigned long *bitmap;
+
+ unsigned long next;
+
+ bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
+ if (ram_bulk_stage && nr > base) {
+ next = nr + 1;
+ } else {
+ next = find_next_bit(bitmap, size, nr);
+ }
+
+ *ram_addr_abs = next << TARGET_PAGE_BITS;
+ return (next - base) << TARGET_PAGE_BITS;
+}
+
+static inline bool migration_bitmap_clear_dirty(ram_addr_t addr)
+{
+ bool ret;
+ int nr = addr >> TARGET_PAGE_BITS;
+ unsigned long *bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
+
+ ret = test_and_clear_bit(nr, bitmap);
+
+ if (ret) {
+ migration_dirty_pages--;
+ }
+ return ret;
+}
+
+static void migration_bitmap_sync_range(ram_addr_t start, ram_addr_t length)
+{
+ unsigned long *bitmap;
+ bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
+ migration_dirty_pages +=
+ cpu_physical_memory_sync_dirty_bitmap(bitmap, start, length);
+}
+
+/* Fix me: there are too many global variables used in migration process. */
+static int64_t start_time;
+static int64_t bytes_xfer_prev;
+static int64_t num_dirty_pages_period;
+static uint64_t xbzrle_cache_miss_prev;
+static uint64_t iterations_prev;
+
+static void migration_bitmap_sync_init(void)
+{
+ start_time = 0;
+ bytes_xfer_prev = 0;
+ num_dirty_pages_period = 0;
+ xbzrle_cache_miss_prev = 0;
+ iterations_prev = 0;
+}
+
+/* Called with iothread lock held, to protect ram_list.dirty_memory[] */
+static void migration_bitmap_sync(void)
+{
+ RAMBlock *block;
+ uint64_t num_dirty_pages_init = migration_dirty_pages;
+ MigrationState *s = migrate_get_current();
+ int64_t end_time;
+ int64_t bytes_xfer_now;
+
+ bitmap_sync_count++;
+
+ if (!bytes_xfer_prev) {
+ bytes_xfer_prev = ram_bytes_transferred();
+ }
+
+ if (!start_time) {
+ start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ }
+
+ trace_migration_bitmap_sync_start();
+ address_space_sync_dirty_bitmap(&address_space_memory);
+
+ qemu_mutex_lock(&migration_bitmap_mutex);
+ rcu_read_lock();
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+ migration_bitmap_sync_range(block->offset, block->used_length);
+ }
+ rcu_read_unlock();
+ qemu_mutex_unlock(&migration_bitmap_mutex);
+
+ trace_migration_bitmap_sync_end(migration_dirty_pages
+ - num_dirty_pages_init);
+ num_dirty_pages_period += migration_dirty_pages - num_dirty_pages_init;
+ end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+
+ /* more than 1 second = 1000 millisecons */
+ if (end_time > start_time + 1000) {
+ 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 twice, start or increase
+ throttling */
+ 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++ >= 2)) {
+ trace_migration_throttle();
+ dirty_rate_high_cnt = 0;
+ mig_throttle_guest_down();
+ }
+ bytes_xfer_prev = bytes_xfer_now;
+ }
+
+ if (migrate_use_xbzrle()) {
+ if (iterations_prev != acct_info.iterations) {
+ 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;
+ }
+ s->dirty_pages_rate = num_dirty_pages_period * 1000
+ / (end_time - start_time);
+ s->dirty_bytes_rate = s->dirty_pages_rate * TARGET_PAGE_SIZE;
+ start_time = end_time;
+ num_dirty_pages_period = 0;
+ }
+ s->dirty_sync_count = bitmap_sync_count;
+}
+
+/**
+ * save_zero_page: Send the zero page to the stream
+ *
+ * Returns: Number of pages written.
+ *
+ * @f: QEMUFile where to send the data
+ * @block: block that contains the page we want to send
+ * @offset: offset inside the block for the page
+ * @p: pointer to the page
+ * @bytes_transferred: increase it with the number of transferred bytes
+ */
+static int save_zero_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset,
+ uint8_t *p, uint64_t *bytes_transferred)
+{
+ int pages = -1;
+
+ if (is_zero_range(p, TARGET_PAGE_SIZE)) {
+ acct_info.dup_pages++;
+ *bytes_transferred += save_page_header(f, block,
+ offset | RAM_SAVE_FLAG_COMPRESS);
+ qemu_put_byte(f, 0);
+ *bytes_transferred += 1;
+ pages = 1;
+ }
+
+ return pages;
+}
+
+/**
+ * ram_save_page: Send the given page to the stream
+ *
+ * Returns: Number of pages written.
+ * < 0 - error
+ * >=0 - Number of pages written - this might legally be 0
+ * if xbzrle noticed the page was the same.
+ *
+ * @f: QEMUFile where to send the data
+ * @block: block that contains the page we want to send
+ * @offset: offset inside the block for the page
+ * @last_stage: if we are at the completion stage
+ * @bytes_transferred: increase it with the number of transferred bytes
+ */
+static int ram_save_page(QEMUFile *f, RAMBlock* block, ram_addr_t offset,
+ bool last_stage, uint64_t *bytes_transferred)
+{
+ int pages = -1;
+ uint64_t bytes_xmit;
+ ram_addr_t current_addr;
+ uint8_t *p;
+ int ret;
+ bool send_async = true;
+
+ p = block->host + offset;
+
+ /* In doubt sent page as normal */
+ bytes_xmit = 0;
+ ret = ram_control_save_page(f, block->offset,
+ offset, TARGET_PAGE_SIZE, &bytes_xmit);
+ if (bytes_xmit) {
+ *bytes_transferred += bytes_xmit;
+ pages = 1;
+ }
+
+ XBZRLE_cache_lock();
+
+ current_addr = block->offset + offset;
+
+ if (block == last_sent_block) {
+ offset |= RAM_SAVE_FLAG_CONTINUE;
+ }
+ if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
+ if (ret != RAM_SAVE_CONTROL_DELAYED) {
+ if (bytes_xmit > 0) {
+ acct_info.norm_pages++;
+ } else if (bytes_xmit == 0) {
+ acct_info.dup_pages++;
+ }
+ }
+ } else {
+ pages = save_zero_page(f, block, offset, p, bytes_transferred);
+ if (pages > 0) {
+ /* 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()) {
+ pages = save_xbzrle_page(f, &p, current_addr, block,
+ offset, last_stage, bytes_transferred);
+ 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 (pages == -1) {
+ *bytes_transferred += save_page_header(f, block,
+ offset | 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_transferred += TARGET_PAGE_SIZE;
+ pages = 1;
+ acct_info.norm_pages++;
+ }
+
+ XBZRLE_cache_unlock();
+
+ return pages;
+}
+
+static int do_compress_ram_page(CompressParam *param)
+{
+ int bytes_sent, blen;
+ uint8_t *p;
+ RAMBlock *block = param->block;
+ ram_addr_t offset = param->offset;
+
+ p = block->host + (offset & TARGET_PAGE_MASK);
+
+ bytes_sent = save_page_header(param->file, block, offset |
+ RAM_SAVE_FLAG_COMPRESS_PAGE);
+ blen = qemu_put_compression_data(param->file, p, TARGET_PAGE_SIZE,
+ migrate_compress_level());
+ bytes_sent += blen;
+
+ return bytes_sent;
+}
+
+static inline void start_compression(CompressParam *param)
+{
+ param->done = false;
+ qemu_mutex_lock(&param->mutex);
+ param->start = true;
+ qemu_cond_signal(&param->cond);
+ qemu_mutex_unlock(&param->mutex);
+}
+
+static inline void start_decompression(DecompressParam *param)
+{
+ qemu_mutex_lock(&param->mutex);
+ param->start = true;
+ qemu_cond_signal(&param->cond);
+ qemu_mutex_unlock(&param->mutex);
+}
+
+static uint64_t bytes_transferred;
+
+static void flush_compressed_data(QEMUFile *f)
+{
+ int idx, len, thread_count;
+
+ if (!migrate_use_compression()) {
+ return;
+ }
+ thread_count = migrate_compress_threads();
+ for (idx = 0; idx < thread_count; idx++) {
+ if (!comp_param[idx].done) {
+ qemu_mutex_lock(comp_done_lock);
+ while (!comp_param[idx].done && !quit_comp_thread) {
+ qemu_cond_wait(comp_done_cond, comp_done_lock);
+ }
+ qemu_mutex_unlock(comp_done_lock);
+ }
+ if (!quit_comp_thread) {
+ len = qemu_put_qemu_file(f, comp_param[idx].file);
+ bytes_transferred += len;
+ }
+ }
+}
+
+static inline void set_compress_params(CompressParam *param, RAMBlock *block,
+ ram_addr_t offset)
+{
+ param->block = block;
+ param->offset = offset;
+}
+
+static int compress_page_with_multi_thread(QEMUFile *f, RAMBlock *block,
+ ram_addr_t offset,
+ uint64_t *bytes_transferred)
+{
+ int idx, thread_count, bytes_xmit = -1, pages = -1;
+
+ thread_count = migrate_compress_threads();
+ qemu_mutex_lock(comp_done_lock);
+ while (true) {
+ for (idx = 0; idx < thread_count; idx++) {
+ if (comp_param[idx].done) {
+ bytes_xmit = qemu_put_qemu_file(f, comp_param[idx].file);
+ set_compress_params(&comp_param[idx], block, offset);
+ start_compression(&comp_param[idx]);
+ pages = 1;
+ acct_info.norm_pages++;
+ *bytes_transferred += bytes_xmit;
+ break;
+ }
+ }
+ if (pages > 0) {
+ break;
+ } else {
+ qemu_cond_wait(comp_done_cond, comp_done_lock);
+ }
+ }
+ qemu_mutex_unlock(comp_done_lock);
+
+ return pages;
+}
+
+/**
+ * ram_save_compressed_page: compress the given page and send it to the stream
+ *
+ * Returns: Number of pages written.
+ *
+ * @f: QEMUFile where to send the data
+ * @block: block that contains the page we want to send
+ * @offset: offset inside the block for the page
+ * @last_stage: if we are at the completion stage
+ * @bytes_transferred: increase it with the number of transferred bytes
+ */
+static int ram_save_compressed_page(QEMUFile *f, RAMBlock *block,
+ ram_addr_t offset, bool last_stage,
+ uint64_t *bytes_transferred)
+{
+ int pages = -1;
+ uint64_t bytes_xmit;
+ uint8_t *p;
+ int ret;
+
+ p = block->host + offset;
+
+ bytes_xmit = 0;
+ ret = ram_control_save_page(f, block->offset,
+ offset, TARGET_PAGE_SIZE, &bytes_xmit);
+ if (bytes_xmit) {
+ *bytes_transferred += bytes_xmit;
+ pages = 1;
+ }
+ if (block == last_sent_block) {
+ offset |= RAM_SAVE_FLAG_CONTINUE;
+ }
+ if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
+ if (ret != RAM_SAVE_CONTROL_DELAYED) {
+ if (bytes_xmit > 0) {
+ acct_info.norm_pages++;
+ } else if (bytes_xmit == 0) {
+ acct_info.dup_pages++;
+ }
+ }
+ } else {
+ /* When starting the process of a new block, the first page of
+ * the block should be sent out before other pages in the same
+ * block, and all the pages in last block should have been sent
+ * out, keeping this order is important, because the 'cont' flag
+ * is used to avoid resending the block name.
+ */
+ if (block != last_sent_block) {
+ flush_compressed_data(f);
+ pages = save_zero_page(f, block, offset, p, bytes_transferred);
+ if (pages == -1) {
+ set_compress_params(&comp_param[0], block, offset);
+ /* Use the qemu thread to compress the data to make sure the
+ * first page is sent out before other pages
+ */
+ bytes_xmit = do_compress_ram_page(&comp_param[0]);
+ acct_info.norm_pages++;
+ qemu_put_qemu_file(f, comp_param[0].file);
+ *bytes_transferred += bytes_xmit;
+ pages = 1;
+ }
+ } else {
+ pages = save_zero_page(f, block, offset, p, bytes_transferred);
+ if (pages == -1) {
+ pages = compress_page_with_multi_thread(f, block, offset,
+ bytes_transferred);
+ }
+ }
+ }
+
+ return pages;
+}
+
+/*
+ * Find the next dirty page and update any state associated with
+ * the search process.
+ *
+ * Returns: True if a page is found
+ *
+ * @f: Current migration stream.
+ * @pss: Data about the state of the current dirty page scan.
+ * @*again: Set to false if the search has scanned the whole of RAM
+ * *ram_addr_abs: Pointer into which to store the address of the dirty page
+ * within the global ram_addr space
+ */
+static bool find_dirty_block(QEMUFile *f, PageSearchStatus *pss,
+ bool *again, ram_addr_t *ram_addr_abs)
+{
+ pss->offset = migration_bitmap_find_dirty(pss->block, pss->offset,
+ ram_addr_abs);
+ if (pss->complete_round && pss->block == last_seen_block &&
+ pss->offset >= last_offset) {
+ /*
+ * We've been once around the RAM and haven't found anything.
+ * Give up.
+ */
+ *again = false;
+ return false;
+ }
+ if (pss->offset >= pss->block->used_length) {
+ /* Didn't find anything in this RAM Block */
+ pss->offset = 0;
+ pss->block = QLIST_NEXT_RCU(pss->block, next);
+ if (!pss->block) {
+ /* Hit the end of the list */
+ pss->block = QLIST_FIRST_RCU(&ram_list.blocks);
+ /* Flag that we've looped */
+ pss->complete_round = true;
+ ram_bulk_stage = false;
+ if (migrate_use_xbzrle()) {
+ /* If xbzrle is on, stop using the data compression at this
+ * point. In theory, xbzrle can do better than compression.
+ */
+ flush_compressed_data(f);
+ compression_switch = false;
+ }
+ }
+ /* Didn't find anything this time, but try again on the new block */
+ *again = true;
+ return false;
+ } else {
+ /* Can go around again, but... */
+ *again = true;
+ /* We've found something so probably don't need to */
+ return true;
+ }
+}
+
+/*
+ * Helper for 'get_queued_page' - gets a page off the queue
+ * ms: MigrationState in
+ * *offset: Used to return the offset within the RAMBlock
+ * ram_addr_abs: global offset in the dirty/sent bitmaps
+ *
+ * Returns: block (or NULL if none available)
+ */
+static RAMBlock *unqueue_page(MigrationState *ms, ram_addr_t *offset,
+ ram_addr_t *ram_addr_abs)
+{
+ RAMBlock *block = NULL;
+
+ qemu_mutex_lock(&ms->src_page_req_mutex);
+ if (!QSIMPLEQ_EMPTY(&ms->src_page_requests)) {
+ struct MigrationSrcPageRequest *entry =
+ QSIMPLEQ_FIRST(&ms->src_page_requests);
+ block = entry->rb;
+ *offset = entry->offset;
+ *ram_addr_abs = (entry->offset + entry->rb->offset) &
+ TARGET_PAGE_MASK;
+
+ if (entry->len > TARGET_PAGE_SIZE) {
+ entry->len -= TARGET_PAGE_SIZE;
+ entry->offset += TARGET_PAGE_SIZE;
+ } else {
+ memory_region_unref(block->mr);
+ QSIMPLEQ_REMOVE_HEAD(&ms->src_page_requests, next_req);
+ g_free(entry);
+ }
+ }
+ qemu_mutex_unlock(&ms->src_page_req_mutex);
+
+ return block;
+}
+
+/*
+ * Unqueue a page from the queue fed by postcopy page requests; skips pages
+ * that are already sent (!dirty)
+ *
+ * ms: MigrationState in
+ * pss: PageSearchStatus structure updated with found block/offset
+ * ram_addr_abs: global offset in the dirty/sent bitmaps
+ *
+ * Returns: true if a queued page is found
+ */
+static bool get_queued_page(MigrationState *ms, PageSearchStatus *pss,
+ ram_addr_t *ram_addr_abs)
+{
+ RAMBlock *block;
+ ram_addr_t offset;
+ bool dirty;
+
+ do {
+ block = unqueue_page(ms, &offset, ram_addr_abs);
+ /*
+ * We're sending this page, and since it's postcopy nothing else
+ * will dirty it, and we must make sure it doesn't get sent again
+ * even if this queue request was received after the background
+ * search already sent it.
+ */
+ if (block) {
+ unsigned long *bitmap;
+ bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
+ dirty = test_bit(*ram_addr_abs >> TARGET_PAGE_BITS, bitmap);
+ if (!dirty) {
+ trace_get_queued_page_not_dirty(
+ block->idstr, (uint64_t)offset,
+ (uint64_t)*ram_addr_abs,
+ test_bit(*ram_addr_abs >> TARGET_PAGE_BITS,
+ atomic_rcu_read(&migration_bitmap_rcu)->unsentmap));
+ } else {
+ trace_get_queued_page(block->idstr,
+ (uint64_t)offset,
+ (uint64_t)*ram_addr_abs);
+ }
+ }
+
+ } while (block && !dirty);
+
+ if (block) {
+ /*
+ * As soon as we start servicing pages out of order, then we have
+ * to kill the bulk stage, since the bulk stage assumes
+ * in (migration_bitmap_find_and_reset_dirty) that every page is
+ * dirty, that's no longer true.
+ */
+ ram_bulk_stage = false;
+
+ /*
+ * We want the background search to continue from the queued page
+ * since the guest is likely to want other pages near to the page
+ * it just requested.
+ */
+ pss->block = block;
+ pss->offset = offset;
+ }
+
+ return !!block;
+}
+
+/**
+ * flush_page_queue: Flush any remaining pages in the ram request queue
+ * it should be empty at the end anyway, but in error cases there may be
+ * some left.
+ *
+ * ms: MigrationState
+ */
+void flush_page_queue(MigrationState *ms)
+{
+ struct MigrationSrcPageRequest *mspr, *next_mspr;
+ /* This queue generally should be empty - but in the case of a failed
+ * migration might have some droppings in.
+ */
+ rcu_read_lock();
+ QSIMPLEQ_FOREACH_SAFE(mspr, &ms->src_page_requests, next_req, next_mspr) {
+ memory_region_unref(mspr->rb->mr);
+ QSIMPLEQ_REMOVE_HEAD(&ms->src_page_requests, next_req);
+ g_free(mspr);
+ }
+ rcu_read_unlock();
+}
+
+/**
+ * Queue the pages for transmission, e.g. a request from postcopy destination
+ * ms: MigrationStatus in which the queue is held
+ * rbname: The RAMBlock the request is for - may be NULL (to mean reuse last)
+ * start: Offset from the start of the RAMBlock
+ * len: Length (in bytes) to send
+ * Return: 0 on success
+ */
+int ram_save_queue_pages(MigrationState *ms, const char *rbname,
+ ram_addr_t start, ram_addr_t len)
+{
+ RAMBlock *ramblock;
+
+ rcu_read_lock();
+ if (!rbname) {
+ /* Reuse last RAMBlock */
+ ramblock = ms->last_req_rb;
+
+ if (!ramblock) {
+ /*
+ * Shouldn't happen, we can't reuse the last RAMBlock if
+ * it's the 1st request.
+ */
+ error_report("ram_save_queue_pages no previous block");
+ goto err;
+ }
+ } else {
+ ramblock = qemu_ram_block_by_name(rbname);
+
+ if (!ramblock) {
+ /* We shouldn't be asked for a non-existent RAMBlock */
+ error_report("ram_save_queue_pages no block '%s'", rbname);
+ goto err;
+ }
+ ms->last_req_rb = ramblock;
+ }
+ trace_ram_save_queue_pages(ramblock->idstr, start, len);
+ if (start+len > ramblock->used_length) {
+ error_report("%s request overrun start=" RAM_ADDR_FMT " len="
+ RAM_ADDR_FMT " blocklen=" RAM_ADDR_FMT,
+ __func__, start, len, ramblock->used_length);
+ goto err;
+ }
+
+ struct MigrationSrcPageRequest *new_entry =
+ g_malloc0(sizeof(struct MigrationSrcPageRequest));
+ new_entry->rb = ramblock;
+ new_entry->offset = start;
+ new_entry->len = len;
+
+ memory_region_ref(ramblock->mr);
+ qemu_mutex_lock(&ms->src_page_req_mutex);
+ QSIMPLEQ_INSERT_TAIL(&ms->src_page_requests, new_entry, next_req);
+ qemu_mutex_unlock(&ms->src_page_req_mutex);
+ rcu_read_unlock();
+
+ return 0;
+
+err:
+ rcu_read_unlock();
+ return -1;
+}
+
+/**
+ * ram_save_target_page: Save one target page
+ *
+ *
+ * @f: QEMUFile where to send the data
+ * @block: pointer to block that contains the page we want to send
+ * @offset: offset inside the block for the page;
+ * @last_stage: if we are at the completion stage
+ * @bytes_transferred: increase it with the number of transferred bytes
+ * @dirty_ram_abs: Address of the start of the dirty page in ram_addr_t space
+ *
+ * Returns: Number of pages written.
+ */
+static int ram_save_target_page(MigrationState *ms, QEMUFile *f,
+ RAMBlock *block, ram_addr_t offset,
+ bool last_stage,
+ uint64_t *bytes_transferred,
+ ram_addr_t dirty_ram_abs)
+{
+ int res = 0;
+
+ /* Check the pages is dirty and if it is send it */
+ if (migration_bitmap_clear_dirty(dirty_ram_abs)) {
+ unsigned long *unsentmap;
+ if (compression_switch && migrate_use_compression()) {
+ res = ram_save_compressed_page(f, block, offset,
+ last_stage,
+ bytes_transferred);
+ } else {
+ res = ram_save_page(f, block, offset, last_stage,
+ bytes_transferred);
+ }
+
+ if (res < 0) {
+ return res;
+ }
+ unsentmap = atomic_rcu_read(&migration_bitmap_rcu)->unsentmap;
+ if (unsentmap) {
+ clear_bit(dirty_ram_abs >> TARGET_PAGE_BITS, unsentmap);
+ }
+ /* Only update last_sent_block if a block was actually sent; xbzrle
+ * might have decided the page was identical so didn't bother writing
+ * to the stream.
+ */
+ if (res > 0) {
+ last_sent_block = block;
+ }
+ }
+
+ return res;
+}
+
+/**
+ * ram_save_host_page: Starting at *offset send pages upto the end
+ * of the current host page. It's valid for the initial
+ * offset to point into the middle of a host page
+ * in which case the remainder of the hostpage is sent.
+ * Only dirty target pages are sent.
+ *
+ * Returns: Number of pages written.
+ *
+ * @f: QEMUFile where to send the data
+ * @block: pointer to block that contains the page we want to send
+ * @offset: offset inside the block for the page; updated to last target page
+ * sent
+ * @last_stage: if we are at the completion stage
+ * @bytes_transferred: increase it with the number of transferred bytes
+ * @dirty_ram_abs: Address of the start of the dirty page in ram_addr_t space
+ */
+static int ram_save_host_page(MigrationState *ms, QEMUFile *f, RAMBlock *block,
+ ram_addr_t *offset, bool last_stage,
+ uint64_t *bytes_transferred,
+ ram_addr_t dirty_ram_abs)
+{
+ int tmppages, pages = 0;
+ do {
+ tmppages = ram_save_target_page(ms, f, block, *offset, last_stage,
+ bytes_transferred, dirty_ram_abs);
+ if (tmppages < 0) {
+ return tmppages;
+ }
+
+ pages += tmppages;
+ *offset += TARGET_PAGE_SIZE;
+ dirty_ram_abs += TARGET_PAGE_SIZE;
+ } while (*offset & (qemu_host_page_size - 1));
+
+ /* The offset we leave with is the last one we looked at */
+ *offset -= TARGET_PAGE_SIZE;
+ return pages;
+}
+
+/**
+ * ram_find_and_save_block: Finds a dirty page and sends it to f
+ *
+ * Called within an RCU critical section.
+ *
+ * Returns: The number of pages written
+ * 0 means no dirty pages
+ *
+ * @f: QEMUFile where to send the data
+ * @last_stage: if we are at the completion stage
+ * @bytes_transferred: increase it with the number of transferred bytes
+ *
+ * On systems where host-page-size > target-page-size it will send all the
+ * pages in a host page that are dirty.
+ */
+
+static int ram_find_and_save_block(QEMUFile *f, bool last_stage,
+ uint64_t *bytes_transferred)
+{
+ PageSearchStatus pss;
+ MigrationState *ms = migrate_get_current();
+ int pages = 0;
+ bool again, found;
+ ram_addr_t dirty_ram_abs; /* Address of the start of the dirty page in
+ ram_addr_t space */
+
+ pss.block = last_seen_block;
+ pss.offset = last_offset;
+ pss.complete_round = false;
+
+ if (!pss.block) {
+ pss.block = QLIST_FIRST_RCU(&ram_list.blocks);
+ }
+
+ do {
+ again = true;
+ found = get_queued_page(ms, &pss, &dirty_ram_abs);
+
+ if (!found) {
+ /* priority queue empty, so just search for something dirty */
+ found = find_dirty_block(f, &pss, &again, &dirty_ram_abs);
+ }
+
+ if (found) {
+ pages = ram_save_host_page(ms, f, pss.block, &pss.offset,
+ last_stage, bytes_transferred,
+ dirty_ram_abs);
+ }
+ } while (!pages && again);
+
+ last_seen_block = pss.block;
+ last_offset = pss.offset;
+
+ return pages;
+}
+
+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);
+ }
+}
+
+static ram_addr_t ram_save_remaining(void)
+{
+ return migration_dirty_pages;
+}
+
+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)
+{
+ RAMBlock *block;
+ uint64_t total = 0;
+
+ rcu_read_lock();
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next)
+ total += block->used_length;
+ rcu_read_unlock();
+ return total;
+}
+
+void free_xbzrle_decoded_buf(void)
+{
+ g_free(xbzrle_decoded_buf);
+ xbzrle_decoded_buf = NULL;
+}
+
+static void migration_bitmap_free(struct BitmapRcu *bmap)
+{
+ g_free(bmap->bmap);
+ g_free(bmap->unsentmap);
+ g_free(bmap);
+}
+
+static void ram_migration_cleanup(void *opaque)
+{
+ /* caller have hold iothread lock or is in a bh, so there is
+ * no writing race against this migration_bitmap
+ */
+ struct BitmapRcu *bitmap = migration_bitmap_rcu;
+ atomic_rcu_set(&migration_bitmap_rcu, NULL);
+ if (bitmap) {
+ memory_global_dirty_log_stop();
+ call_rcu(bitmap, migration_bitmap_free, rcu);
+ }
+
+ XBZRLE_cache_lock();
+ if (XBZRLE.cache) {
+ cache_fini(XBZRLE.cache);
+ g_free(XBZRLE.encoded_buf);
+ g_free(XBZRLE.current_buf);
+ XBZRLE.cache = NULL;
+ XBZRLE.encoded_buf = NULL;
+ XBZRLE.current_buf = NULL;
+ }
+ XBZRLE_cache_unlock();
+}
+
+static void reset_ram_globals(void)
+{
+ last_seen_block = NULL;
+ last_sent_block = NULL;
+ last_offset = 0;
+ last_version = ram_list.version;
+ ram_bulk_stage = true;
+}
+
+#define MAX_WAIT 50 /* ms, half buffered_file limit */
+
+void migration_bitmap_extend(ram_addr_t old, ram_addr_t new)
+{
+ /* called in qemu main thread, so there is
+ * no writing race against this migration_bitmap
+ */
+ if (migration_bitmap_rcu) {
+ struct BitmapRcu *old_bitmap = migration_bitmap_rcu, *bitmap;
+ bitmap = g_new(struct BitmapRcu, 1);
+ bitmap->bmap = bitmap_new(new);
+
+ /* prevent migration_bitmap content from being set bit
+ * by migration_bitmap_sync_range() at the same time.
+ * it is safe to migration if migration_bitmap is cleared bit
+ * at the same time.
+ */
+ qemu_mutex_lock(&migration_bitmap_mutex);
+ bitmap_copy(bitmap->bmap, old_bitmap->bmap, old);
+ bitmap_set(bitmap->bmap, old, new - old);
+
+ /* We don't have a way to safely extend the sentmap
+ * with RCU; so mark it as missing, entry to postcopy
+ * will fail.
+ */
+ bitmap->unsentmap = NULL;
+
+ atomic_rcu_set(&migration_bitmap_rcu, bitmap);
+ qemu_mutex_unlock(&migration_bitmap_mutex);
+ migration_dirty_pages += new - old;
+ call_rcu(old_bitmap, migration_bitmap_free, rcu);
+ }
+}
+
+/*
+ * 'expected' is the value you expect the bitmap mostly to be full
+ * of; it won't bother printing lines that are all this value.
+ * If 'todump' is null the migration bitmap is dumped.
+ */
+void ram_debug_dump_bitmap(unsigned long *todump, bool expected)
+{
+ int64_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
+
+ int64_t cur;
+ int64_t linelen = 128;
+ char linebuf[129];
+
+ if (!todump) {
+ todump = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
+ }
+
+ for (cur = 0; cur < ram_pages; cur += linelen) {
+ int64_t curb;
+ bool found = false;
+ /*
+ * Last line; catch the case where the line length
+ * is longer than remaining ram
+ */
+ if (cur + linelen > ram_pages) {
+ linelen = ram_pages - cur;
+ }
+ for (curb = 0; curb < linelen; curb++) {
+ bool thisbit = test_bit(cur + curb, todump);
+ linebuf[curb] = thisbit ? '1' : '.';
+ found = found || (thisbit != expected);
+ }
+ if (found) {
+ linebuf[curb] = '\0';
+ fprintf(stderr, "0x%08" PRIx64 " : %s\n", cur, linebuf);
+ }
+ }
+}
+
+/* **** functions for postcopy ***** */
+
+/*
+ * Callback from postcopy_each_ram_send_discard for each RAMBlock
+ * Note: At this point the 'unsentmap' is the processed bitmap combined
+ * with the dirtymap; so a '1' means it's either dirty or unsent.
+ * start,length: Indexes into the bitmap for the first bit
+ * representing the named block and length in target-pages
+ */
+static int postcopy_send_discard_bm_ram(MigrationState *ms,
+ PostcopyDiscardState *pds,
+ unsigned long start,
+ unsigned long length)
+{
+ unsigned long end = start + length; /* one after the end */
+ unsigned long current;
+ unsigned long *unsentmap;
+
+ unsentmap = atomic_rcu_read(&migration_bitmap_rcu)->unsentmap;
+ for (current = start; current < end; ) {
+ unsigned long one = find_next_bit(unsentmap, end, current);
+
+ if (one <= end) {
+ unsigned long zero = find_next_zero_bit(unsentmap, end, one + 1);
+ unsigned long discard_length;
+
+ if (zero >= end) {
+ discard_length = end - one;
+ } else {
+ discard_length = zero - one;
+ }
+ postcopy_discard_send_range(ms, pds, one, discard_length);
+ current = one + discard_length;
+ } else {
+ current = one;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Utility for the outgoing postcopy code.
+ * Calls postcopy_send_discard_bm_ram for each RAMBlock
+ * passing it bitmap indexes and name.
+ * Returns: 0 on success
+ * (qemu_ram_foreach_block ends up passing unscaled lengths
+ * which would mean postcopy code would have to deal with target page)
+ */
+static int postcopy_each_ram_send_discard(MigrationState *ms)
+{
+ struct RAMBlock *block;
+ int ret;
+
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+ unsigned long first = block->offset >> TARGET_PAGE_BITS;
+ PostcopyDiscardState *pds = postcopy_discard_send_init(ms,
+ first,
+ block->idstr);
+
+ /*
+ * Postcopy sends chunks of bitmap over the wire, but it
+ * just needs indexes at this point, avoids it having
+ * target page specific code.
+ */
+ ret = postcopy_send_discard_bm_ram(ms, pds, first,
+ block->used_length >> TARGET_PAGE_BITS);
+ postcopy_discard_send_finish(ms, pds);
+ if (ret) {
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Helper for postcopy_chunk_hostpages; it's called twice to cleanup
+ * the two bitmaps, that are similar, but one is inverted.
+ *
+ * We search for runs of target-pages that don't start or end on a
+ * host page boundary;
+ * unsent_pass=true: Cleans up partially unsent host pages by searching
+ * the unsentmap
+ * unsent_pass=false: Cleans up partially dirty host pages by searching
+ * the main migration bitmap
+ *
+ */
+static void postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
+ RAMBlock *block,
+ PostcopyDiscardState *pds)
+{
+ unsigned long *bitmap;
+ unsigned long *unsentmap;
+ unsigned int host_ratio = qemu_host_page_size / TARGET_PAGE_SIZE;
+ unsigned long first = block->offset >> TARGET_PAGE_BITS;
+ unsigned long len = block->used_length >> TARGET_PAGE_BITS;
+ unsigned long last = first + (len - 1);
+ unsigned long run_start;
+
+ bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
+ unsentmap = atomic_rcu_read(&migration_bitmap_rcu)->unsentmap;
+
+ if (unsent_pass) {
+ /* Find a sent page */
+ run_start = find_next_zero_bit(unsentmap, last + 1, first);
+ } else {
+ /* Find a dirty page */
+ run_start = find_next_bit(bitmap, last + 1, first);
+ }
+
+ while (run_start <= last) {
+ bool do_fixup = false;
+ unsigned long fixup_start_addr;
+ unsigned long host_offset;
+
+ /*
+ * If the start of this run of pages is in the middle of a host
+ * page, then we need to fixup this host page.
+ */
+ host_offset = run_start % host_ratio;
+ if (host_offset) {
+ do_fixup = true;
+ run_start -= host_offset;
+ fixup_start_addr = run_start;
+ /* For the next pass */
+ run_start = run_start + host_ratio;
+ } else {
+ /* Find the end of this run */
+ unsigned long run_end;
+ if (unsent_pass) {
+ run_end = find_next_bit(unsentmap, last + 1, run_start + 1);
+ } else {
+ run_end = find_next_zero_bit(bitmap, last + 1, run_start + 1);
+ }
+ /*
+ * If the end isn't at the start of a host page, then the
+ * run doesn't finish at the end of a host page
+ * and we need to discard.
+ */
+ host_offset = run_end % host_ratio;
+ if (host_offset) {
+ do_fixup = true;
+ fixup_start_addr = run_end - host_offset;
+ /*
+ * This host page has gone, the next loop iteration starts
+ * from after the fixup
+ */
+ run_start = fixup_start_addr + host_ratio;
+ } else {
+ /*
+ * No discards on this iteration, next loop starts from
+ * next sent/dirty page
+ */
+ run_start = run_end + 1;
+ }
+ }
+
+ if (do_fixup) {
+ unsigned long page;
+
+ /* Tell the destination to discard this page */
+ if (unsent_pass || !test_bit(fixup_start_addr, unsentmap)) {
+ /* For the unsent_pass we:
+ * discard partially sent pages
+ * For the !unsent_pass (dirty) we:
+ * discard partially dirty pages that were sent
+ * (any partially sent pages were already discarded
+ * by the previous unsent_pass)
+ */
+ postcopy_discard_send_range(ms, pds, fixup_start_addr,
+ host_ratio);
+ }
+
+ /* Clean up the bitmap */
+ for (page = fixup_start_addr;
+ page < fixup_start_addr + host_ratio; page++) {
+ /* All pages in this host page are now not sent */
+ set_bit(page, unsentmap);
+
+ /*
+ * Remark them as dirty, updating the count for any pages
+ * that weren't previously dirty.
+ */
+ migration_dirty_pages += !test_and_set_bit(page, bitmap);
+ }
+ }
+
+ if (unsent_pass) {
+ /* Find the next sent page for the next iteration */
+ run_start = find_next_zero_bit(unsentmap, last + 1,
+ run_start);
+ } else {
+ /* Find the next dirty page for the next iteration */
+ run_start = find_next_bit(bitmap, last + 1, run_start);
+ }
+ }
+}
+
+/*
+ * Utility for the outgoing postcopy code.
+ *
+ * Discard any partially sent host-page size chunks, mark any partially
+ * dirty host-page size chunks as all dirty.
+ *
+ * Returns: 0 on success
+ */
+static int postcopy_chunk_hostpages(MigrationState *ms)
+{
+ struct RAMBlock *block;
+
+ if (qemu_host_page_size == TARGET_PAGE_SIZE) {
+ /* Easy case - TPS==HPS - nothing to be done */
+ return 0;
+ }
+
+ /* Easiest way to make sure we don't resume in the middle of a host-page */
+ last_seen_block = NULL;
+ last_sent_block = NULL;
+ last_offset = 0;
+
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+ unsigned long first = block->offset >> TARGET_PAGE_BITS;
+
+ PostcopyDiscardState *pds =
+ postcopy_discard_send_init(ms, first, block->idstr);
+
+ /* First pass: Discard all partially sent host pages */
+ postcopy_chunk_hostpages_pass(ms, true, block, pds);
+ /*
+ * Second pass: Ensure that all partially dirty host pages are made
+ * fully dirty.
+ */
+ postcopy_chunk_hostpages_pass(ms, false, block, pds);
+
+ postcopy_discard_send_finish(ms, pds);
+ } /* ram_list loop */
+
+ return 0;
+}
+
+/*
+ * Transmit the set of pages to be discarded after precopy to the target
+ * these are pages that:
+ * a) Have been previously transmitted but are now dirty again
+ * b) Pages that have never been transmitted, this ensures that
+ * any pages on the destination that have been mapped by background
+ * tasks get discarded (transparent huge pages is the specific concern)
+ * Hopefully this is pretty sparse
+ */
+int ram_postcopy_send_discard_bitmap(MigrationState *ms)
+{
+ int ret;
+ unsigned long *bitmap, *unsentmap;
+
+ rcu_read_lock();
+
+ /* This should be our last sync, the src is now paused */
+ migration_bitmap_sync();
+
+ unsentmap = atomic_rcu_read(&migration_bitmap_rcu)->unsentmap;
+ if (!unsentmap) {
+ /* We don't have a safe way to resize the sentmap, so
+ * if the bitmap was resized it will be NULL at this
+ * point.
+ */
+ error_report("migration ram resized during precopy phase");
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+
+ /* Deal with TPS != HPS */
+ ret = postcopy_chunk_hostpages(ms);
+ if (ret) {
+ rcu_read_unlock();
+ return ret;
+ }
+
+ /*
+ * Update the unsentmap to be unsentmap = unsentmap | dirty
+ */
+ bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
+ bitmap_or(unsentmap, unsentmap, bitmap,
+ last_ram_offset() >> TARGET_PAGE_BITS);
+
+
+ trace_ram_postcopy_send_discard_bitmap();
+#ifdef DEBUG_POSTCOPY
+ ram_debug_dump_bitmap(unsentmap, true);
+#endif
+
+ ret = postcopy_each_ram_send_discard(ms);
+ rcu_read_unlock();
+
+ return ret;
+}
+
+/*
+ * At the start of the postcopy phase of migration, any now-dirty
+ * precopied pages are discarded.
+ *
+ * start, length describe a byte address range within the RAMBlock
+ *
+ * Returns 0 on success.
+ */
+int ram_discard_range(MigrationIncomingState *mis,
+ const char *block_name,
+ uint64_t start, size_t length)
+{
+ int ret = -1;
+
+ rcu_read_lock();
+ RAMBlock *rb = qemu_ram_block_by_name(block_name);
+
+ if (!rb) {
+ error_report("ram_discard_range: Failed to find block '%s'",
+ block_name);
+ goto err;
+ }
+
+ uint8_t *host_startaddr = rb->host + start;
+
+ if ((uintptr_t)host_startaddr & (qemu_host_page_size - 1)) {
+ error_report("ram_discard_range: Unaligned start address: %p",
+ host_startaddr);
+ goto err;
+ }
+
+ if ((start + length) <= rb->used_length) {
+ uint8_t *host_endaddr = host_startaddr + length;
+ if ((uintptr_t)host_endaddr & (qemu_host_page_size - 1)) {
+ error_report("ram_discard_range: Unaligned end address: %p",
+ host_endaddr);
+ goto err;
+ }
+ ret = postcopy_ram_discard_range(mis, host_startaddr, length);
+ } else {
+ error_report("ram_discard_range: Overrun block '%s' (%" PRIu64
+ "/%zx/" RAM_ADDR_FMT")",
+ block_name, start, length, rb->used_length);
+ }
+
+err:
+ rcu_read_unlock();
+
+ return ret;
+}
+
+
+/* Each of ram_save_setup, ram_save_iterate and ram_save_complete has
+ * long-running RCU critical section. When rcu-reclaims in the code
+ * start to become numerous it will be necessary to reduce the
+ * granularity of these critical sections.
+ */
+
+static int ram_save_setup(QEMUFile *f, void *opaque)
+{
+ RAMBlock *block;
+ int64_t ram_bitmap_pages; /* Size of bitmap in pages, including gaps */
+
+ dirty_rate_high_cnt = 0;
+ bitmap_sync_count = 0;
+ migration_bitmap_sync_init();
+ qemu_mutex_init(&migration_bitmap_mutex);
+
+ if (migrate_use_xbzrle()) {
+ XBZRLE_cache_lock();
+ XBZRLE.cache = cache_init(migrate_xbzrle_cache_size() /
+ TARGET_PAGE_SIZE,
+ TARGET_PAGE_SIZE);
+ if (!XBZRLE.cache) {
+ XBZRLE_cache_unlock();
+ error_report("Error creating cache");
+ return -1;
+ }
+ XBZRLE_cache_unlock();
+
+ /* We prefer not to abort if there is no memory */
+ XBZRLE.encoded_buf = g_try_malloc0(TARGET_PAGE_SIZE);
+ if (!XBZRLE.encoded_buf) {
+ error_report("Error allocating encoded_buf");
+ return -1;
+ }
+
+ XBZRLE.current_buf = g_try_malloc(TARGET_PAGE_SIZE);
+ if (!XBZRLE.current_buf) {
+ error_report("Error allocating current_buf");
+ g_free(XBZRLE.encoded_buf);
+ XBZRLE.encoded_buf = NULL;
+ return -1;
+ }
+
+ acct_clear();
+ }
+
+ /* iothread lock needed for ram_list.dirty_memory[] */
+ qemu_mutex_lock_iothread();
+ qemu_mutex_lock_ramlist();
+ rcu_read_lock();
+ bytes_transferred = 0;
+ reset_ram_globals();
+
+ ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
+ migration_bitmap_rcu = g_new0(struct BitmapRcu, 1);
+ migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
+ bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
+
+ if (migrate_postcopy_ram()) {
+ migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
+ bitmap_set(migration_bitmap_rcu->unsentmap, 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 = ram_bytes_total() >> TARGET_PAGE_BITS;
+
+ memory_global_dirty_log_start();
+ migration_bitmap_sync();
+ qemu_mutex_unlock_ramlist();
+ qemu_mutex_unlock_iothread();
+
+ qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
+
+ QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+ qemu_put_byte(f, strlen(block->idstr));
+ qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
+ qemu_put_be64(f, block->used_length);
+ }
+
+ rcu_read_unlock();
+
+ ram_control_before_iterate(f, RAM_CONTROL_SETUP);
+ ram_control_after_iterate(f, RAM_CONTROL_SETUP);
+
+ qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
+
+ return 0;
+}
+
+static int ram_save_iterate(QEMUFile *f, void *opaque)
+{
+ int ret;
+ int i;
+ int64_t t0;
+ int pages_sent = 0;
+
+ rcu_read_lock();
+ if (ram_list.version != last_version) {
+ reset_ram_globals();
+ }
+
+ /* Read version before ram_list.blocks */
+ smp_rmb();
+
+ ram_control_before_iterate(f, RAM_CONTROL_ROUND);
+
+ t0 = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+ i = 0;
+ while ((ret = qemu_file_rate_limit(f)) == 0) {
+ int pages;
+
+ pages = ram_find_and_save_block(f, false, &bytes_transferred);
+ /* no more pages to sent */
+ if (pages == 0) {
+ break;
+ }
+ pages_sent += pages;
+ acct_info.iterations++;
+
+ /* 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) {
+ uint64_t t1 = (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - t0) / 1000000;
+ if (t1 > MAX_WAIT) {
+ DPRINTF("big wait: %" PRIu64 " milliseconds, %d iterations\n",
+ t1, i);
+ break;
+ }
+ }
+ i++;
+ }
+ flush_compressed_data(f);
+ rcu_read_unlock();
+
+ /*
+ * Must occur before EOS (or any QEMUFile operation)
+ * because of RDMA protocol.
+ */
+ ram_control_after_iterate(f, RAM_CONTROL_ROUND);
+
+ qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
+ bytes_transferred += 8;
+
+ ret = qemu_file_get_error(f);
+ if (ret < 0) {
+ return ret;
+ }
+
+ return pages_sent;
+}
+
+/* Called with iothread lock */
+static int ram_save_complete(QEMUFile *f, void *opaque)
+{
+ rcu_read_lock();
+
+ if (!migration_in_postcopy(migrate_get_current())) {
+ migration_bitmap_sync();
+ }
+
+ ram_control_before_iterate(f, RAM_CONTROL_FINISH);
+
+ /* try transferring iterative blocks of memory */
+
+ /* flush all remaining blocks regardless of rate limiting */
+ while (true) {
+ int pages;
+
+ pages = ram_find_and_save_block(f, true, &bytes_transferred);
+ /* no more blocks to sent */
+ if (pages == 0) {
+ break;
+ }
+ }
+
+ flush_compressed_data(f);
+ ram_control_after_iterate(f, RAM_CONTROL_FINISH);
+
+ rcu_read_unlock();
+
+ qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
+
+ return 0;
+}
+
+static void ram_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
+ uint64_t *non_postcopiable_pending,
+ uint64_t *postcopiable_pending)
+{
+ uint64_t remaining_size;
+
+ remaining_size = ram_save_remaining() * TARGET_PAGE_SIZE;
+
+ if (!migration_in_postcopy(migrate_get_current()) &&
+ remaining_size < max_size) {
+ qemu_mutex_lock_iothread();
+ rcu_read_lock();
+ migration_bitmap_sync();
+ rcu_read_unlock();
+ qemu_mutex_unlock_iothread();
+ remaining_size = ram_save_remaining() * TARGET_PAGE_SIZE;
+ }
+
+ /* We can do postcopy, and all the data is postcopiable */
+ *postcopiable_pending += remaining_size;
+}
+
+static int load_xbzrle(QEMUFile *f, ram_addr_t addr, void *host)
+{
+ unsigned int xh_len;
+ int xh_flags;
+
+ if (!xbzrle_decoded_buf) {
+ xbzrle_decoded_buf = g_malloc(TARGET_PAGE_SIZE);
+ }
+
+ /* extract RLE header */
+ xh_flags = qemu_get_byte(f);
+ xh_len = qemu_get_be16(f);
+
+ if (xh_flags != ENCODING_FLAG_XBZRLE) {
+ error_report("Failed to load XBZRLE page - wrong compression!");
+ return -1;
+ }
+
+ if (xh_len > TARGET_PAGE_SIZE) {
+ error_report("Failed to load XBZRLE page - len overflow!");
+ return -1;
+ }
+ /* load data and decode */
+ qemu_get_buffer(f, xbzrle_decoded_buf, xh_len);
+
+ /* decode RLE */
+ if (xbzrle_decode_buffer(xbzrle_decoded_buf, xh_len, host,
+ TARGET_PAGE_SIZE) == -1) {
+ error_report("Failed to load XBZRLE page - decode error!");
+ return -1;
+ }
+
+ return 0;
+}
+
+/* Must be called from within a rcu critical section.
+ * Returns a pointer from within the RCU-protected ram_list.
+ */
+/*
+ * Read a RAMBlock ID from the stream f, find the host address of the
+ * start of that block and add on 'offset'
+ *
+ * f: Stream to read from
+ * offset: Offset within the block
+ * flags: Page flags (mostly to see if it's a continuation of previous block)
+ */
+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 || block->max_length <= offset) {
+ error_report("Ack, bad migration stream!");
+ return NULL;
+ }
+
+ return block->host + offset;
+ }
+
+ len = qemu_get_byte(f);
+ qemu_get_buffer(f, (uint8_t *)id, len);
+ id[len] = 0;
+
+ block = qemu_ram_block_by_name(id);
+ if (block && block->max_length > offset) {
+ return block->host + offset;
+ }
+
+ error_report("Can't find block %s", id);
+ return NULL;
+}
+
+/*
+ * 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)
+{
+ if (ch != 0 || !is_zero_range(host, size)) {
+ memset(host, ch, size);
+ }
+}
+
+static void *do_data_decompress(void *opaque)
+{
+ DecompressParam *param = opaque;
+ unsigned long pagesize;
+
+ while (!quit_decomp_thread) {
+ qemu_mutex_lock(&param->mutex);
+ while (!param->start && !quit_decomp_thread) {
+ qemu_cond_wait(&param->cond, &param->mutex);
+ pagesize = TARGET_PAGE_SIZE;
+ if (!quit_decomp_thread) {
+ /* uncompress() will return failed in some case, especially
+ * when the page is dirted when doing the compression, it's
+ * not a problem because the dirty page will be retransferred
+ * and uncompress() won't break the data in other pages.
+ */
+ uncompress((Bytef *)param->des, &pagesize,
+ (const Bytef *)param->compbuf, param->len);
+ }
+ param->start = false;
+ }
+ qemu_mutex_unlock(&param->mutex);
+ }
+
+ return NULL;
+}
+
+void migrate_decompress_threads_create(void)
+{
+ int i, thread_count;
+
+ thread_count = migrate_decompress_threads();
+ decompress_threads = g_new0(QemuThread, thread_count);
+ decomp_param = g_new0(DecompressParam, thread_count);
+ compressed_data_buf = g_malloc0(compressBound(TARGET_PAGE_SIZE));
+ quit_decomp_thread = false;
+ for (i = 0; i < thread_count; i++) {
+ qemu_mutex_init(&decomp_param[i].mutex);
+ qemu_cond_init(&decomp_param[i].cond);
+ decomp_param[i].compbuf = g_malloc0(compressBound(TARGET_PAGE_SIZE));
+ qemu_thread_create(decompress_threads + i, "decompress",
+ do_data_decompress, decomp_param + i,
+ QEMU_THREAD_JOINABLE);
+ }
+}
+
+void migrate_decompress_threads_join(void)
+{
+ int i, thread_count;
+
+ quit_decomp_thread = true;
+ thread_count = migrate_decompress_threads();
+ for (i = 0; i < thread_count; i++) {
+ qemu_mutex_lock(&decomp_param[i].mutex);
+ qemu_cond_signal(&decomp_param[i].cond);
+ qemu_mutex_unlock(&decomp_param[i].mutex);
+ }
+ for (i = 0; i < thread_count; i++) {
+ qemu_thread_join(decompress_threads + i);
+ qemu_mutex_destroy(&decomp_param[i].mutex);
+ qemu_cond_destroy(&decomp_param[i].cond);
+ g_free(decomp_param[i].compbuf);
+ }
+ g_free(decompress_threads);
+ g_free(decomp_param);
+ g_free(compressed_data_buf);
+ decompress_threads = NULL;
+ decomp_param = NULL;
+ compressed_data_buf = NULL;
+}
+
+static void decompress_data_with_multi_threads(uint8_t *compbuf,
+ void *host, int len)
+{
+ int idx, thread_count;
+
+ thread_count = migrate_decompress_threads();
+ while (true) {
+ for (idx = 0; idx < thread_count; idx++) {
+ if (!decomp_param[idx].start) {
+ memcpy(decomp_param[idx].compbuf, compbuf, len);
+ decomp_param[idx].des = host;
+ decomp_param[idx].len = len;
+ start_decompression(&decomp_param[idx]);
+ break;
+ }
+ }
+ if (idx < thread_count) {
+ break;
+ }
+ }
+}
+
+/*
+ * Allocate data structures etc needed by incoming migration with postcopy-ram
+ * postcopy-ram's similarly names postcopy_ram_incoming_init does the work
+ */
+int ram_postcopy_incoming_init(MigrationIncomingState *mis)
+{
+ size_t ram_pages = last_ram_offset() >> TARGET_PAGE_BITS;
+
+ return postcopy_ram_incoming_init(mis, ram_pages);
+}
+
+/*
+ * Called in postcopy mode by ram_load().
+ * rcu_read_lock is taken prior to this being called.
+ */
+static int ram_load_postcopy(QEMUFile *f)
+{
+ int flags = 0, ret = 0;
+ bool place_needed = false;
+ bool matching_page_sizes = qemu_host_page_size == TARGET_PAGE_SIZE;
+ MigrationIncomingState *mis = migration_incoming_get_current();
+ /* Temporary page that is later 'placed' */
+ void *postcopy_host_page = postcopy_get_tmp_page(mis);
+ void *last_host = NULL;
+ bool all_zero = false;
+
+ while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) {
+ ram_addr_t addr;
+ void *host = NULL;
+ void *page_buffer = NULL;
+ void *place_source = NULL;
+ uint8_t ch;
+
+ addr = qemu_get_be64(f);
+ flags = addr & ~TARGET_PAGE_MASK;
+ addr &= TARGET_PAGE_MASK;
+
+ trace_ram_load_postcopy_loop((uint64_t)addr, flags);
+ place_needed = false;
+ if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE)) {
+ host = host_from_stream_offset(f, addr, flags);
+ if (!host) {
+ error_report("Illegal RAM offset " RAM_ADDR_FMT, addr);
+ ret = -EINVAL;
+ break;
+ }
+ page_buffer = host;
+ /*
+ * Postcopy requires that we place whole host pages atomically.
+ * To make it atomic, the data is read into a temporary page
+ * that's moved into place later.
+ * The migration protocol uses, possibly smaller, target-pages
+ * however the source ensures it always sends all the components
+ * of a host page in order.
+ */
+ page_buffer = postcopy_host_page +
+ ((uintptr_t)host & ~qemu_host_page_mask);
+ /* If all TP are zero then we can optimise the place */
+ if (!((uintptr_t)host & ~qemu_host_page_mask)) {
+ all_zero = true;
+ } else {
+ /* not the 1st TP within the HP */
+ if (host != (last_host + TARGET_PAGE_SIZE)) {
+ error_report("Non-sequential target page %p/%p\n",
+ host, last_host);
+ ret = -EINVAL;
+ break;
+ }
+ }
+
+
+ /*
+ * If it's the last part of a host page then we place the host
+ * page
+ */
+ place_needed = (((uintptr_t)host + TARGET_PAGE_SIZE) &
+ ~qemu_host_page_mask) == 0;
+ place_source = postcopy_host_page;
+ }
+ last_host = host;
+
+ switch (flags & ~RAM_SAVE_FLAG_CONTINUE) {
+ case RAM_SAVE_FLAG_COMPRESS:
+ ch = qemu_get_byte(f);
+ memset(page_buffer, ch, TARGET_PAGE_SIZE);
+ if (ch) {
+ all_zero = false;
+ }
+ break;
+
+ case RAM_SAVE_FLAG_PAGE:
+ all_zero = false;
+ if (!place_needed || !matching_page_sizes) {
+ qemu_get_buffer(f, page_buffer, TARGET_PAGE_SIZE);
+ } else {
+ /* Avoids the qemu_file copy during postcopy, which is
+ * going to do a copy later; can only do it when we
+ * do this read in one go (matching page sizes)
+ */
+ qemu_get_buffer_in_place(f, (uint8_t **)&place_source,
+ TARGET_PAGE_SIZE);
+ }
+ break;
+ case RAM_SAVE_FLAG_EOS:
+ /* normal exit */
+ break;
+ default:
+ error_report("Unknown combination of migration flags: %#x"
+ " (postcopy mode)", flags);
+ ret = -EINVAL;
+ }
+
+ if (place_needed) {
+ /* This gets called at the last target page in the host page */
+ if (all_zero) {
+ ret = postcopy_place_page_zero(mis,
+ host + TARGET_PAGE_SIZE -
+ qemu_host_page_size);
+ } else {
+ ret = postcopy_place_page(mis, host + TARGET_PAGE_SIZE -
+ qemu_host_page_size,
+ place_source);
+ }
+ }
+ if (!ret) {
+ ret = qemu_file_get_error(f);
+ }
+ }
+
+ return ret;
+}
+
+static int ram_load(QEMUFile *f, void *opaque, int version_id)
+{
+ int flags = 0, ret = 0;
+ static uint64_t seq_iter;
+ int len = 0;
+ /*
+ * If system is running in postcopy mode, page inserts to host memory must
+ * be atomic
+ */
+ bool postcopy_running = postcopy_state_get() >= POSTCOPY_INCOMING_LISTENING;
+
+ seq_iter++;
+
+ if (version_id != 4) {
+ ret = -EINVAL;
+ }
+
+ /* This RCU critical section can be very long running.
+ * When RCU reclaims in the code start to become numerous,
+ * it will be necessary to reduce the granularity of this
+ * critical section.
+ */
+ rcu_read_lock();
+
+ if (postcopy_running) {
+ ret = ram_load_postcopy(f);
+ }
+
+ while (!postcopy_running && !ret && !(flags & RAM_SAVE_FLAG_EOS)) {
+ ram_addr_t addr, total_ram_bytes;
+ void *host = NULL;
+ uint8_t ch;
+
+ addr = qemu_get_be64(f);
+ flags = addr & ~TARGET_PAGE_MASK;
+ addr &= TARGET_PAGE_MASK;
+
+ if (flags & (RAM_SAVE_FLAG_COMPRESS | RAM_SAVE_FLAG_PAGE |
+ RAM_SAVE_FLAG_COMPRESS_PAGE | RAM_SAVE_FLAG_XBZRLE)) {
+ host = host_from_stream_offset(f, addr, flags);
+ if (!host) {
+ error_report("Illegal RAM offset " RAM_ADDR_FMT, addr);
+ ret = -EINVAL;
+ break;
+ }
+ }
+
+ switch (flags & ~RAM_SAVE_FLAG_CONTINUE) {
+ case RAM_SAVE_FLAG_MEM_SIZE:
+ /* Synchronize RAM block list */
+ total_ram_bytes = addr;
+ while (!ret && total_ram_bytes) {
+ RAMBlock *block;
+ char id[256];
+ ram_addr_t length;
+
+ len = qemu_get_byte(f);
+ qemu_get_buffer(f, (uint8_t *)id, len);
+ id[len] = 0;
+ length = qemu_get_be64(f);
+
+ block = qemu_ram_block_by_name(id);
+ if (block) {
+ if (length != block->used_length) {
+ Error *local_err = NULL;
+
+ ret = qemu_ram_resize(block->offset, length,
+ &local_err);
+ if (local_err) {
+ error_report_err(local_err);
+ }
+ }
+ ram_control_load_hook(f, RAM_CONTROL_BLOCK_REG,
+ block->idstr);
+ } else {
+ error_report("Unknown ramblock \"%s\", cannot "
+ "accept migration", id);
+ ret = -EINVAL;
+ }
+
+ total_ram_bytes -= length;
+ }
+ break;
+
+ case RAM_SAVE_FLAG_COMPRESS:
+ ch = qemu_get_byte(f);
+ ram_handle_compressed(host, ch, TARGET_PAGE_SIZE);
+ break;
+
+ case RAM_SAVE_FLAG_PAGE:
+ qemu_get_buffer(f, host, TARGET_PAGE_SIZE);
+ break;
+
+ case RAM_SAVE_FLAG_COMPRESS_PAGE:
+ len = qemu_get_be32(f);
+ if (len < 0 || len > compressBound(TARGET_PAGE_SIZE)) {
+ error_report("Invalid compressed data length: %d", len);
+ ret = -EINVAL;
+ break;
+ }
+ qemu_get_buffer(f, compressed_data_buf, len);
+ decompress_data_with_multi_threads(compressed_data_buf, host, len);
+ break;
+
+ case RAM_SAVE_FLAG_XBZRLE:
+ if (load_xbzrle(f, addr, host) < 0) {
+ error_report("Failed to decompress XBZRLE page at "
+ RAM_ADDR_FMT, addr);
+ ret = -EINVAL;
+ break;
+ }
+ break;
+ case RAM_SAVE_FLAG_EOS:
+ /* normal exit */
+ break;
+ default:
+ if (flags & RAM_SAVE_FLAG_HOOK) {
+ ram_control_load_hook(f, RAM_CONTROL_HOOK, NULL);
+ } else {
+ error_report("Unknown combination of migration flags: %#x",
+ flags);
+ ret = -EINVAL;
+ }
+ }
+ if (!ret) {
+ ret = qemu_file_get_error(f);
+ }
+ }
+
+ rcu_read_unlock();
+ DPRINTF("Completed load of VM with exit code %d seq iteration "
+ "%" PRIu64 "\n", ret, seq_iter);
+ return ret;
+}
+
+static SaveVMHandlers savevm_ram_handlers = {
+ .save_live_setup = ram_save_setup,
+ .save_live_iterate = ram_save_iterate,
+ .save_live_complete_postcopy = ram_save_complete,
+ .save_live_complete_precopy = ram_save_complete,
+ .save_live_pending = ram_save_pending,
+ .load_state = ram_load,
+ .cleanup = ram_migration_cleanup,
+};
+
+void ram_mig_init(void)
+{
+ qemu_mutex_init(&XBZRLE.lock);
+ register_savevm_live(NULL, "ram", 0, 4, &savevm_ram_handlers, NULL);
+}
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