[RFC PATCH 4/8] migration/dirtyrate: Record hash results for each ramblock

[Chuan Zheng <zhengchuan@huawei.com>]

From: Zheng Chuan <zhengchuan@huawei.com>

Record hash results for each ramblock.

Signed-off-by: Zheng Chuan <zhengchuan@huawei.com>
Signed-off-by: YanYing Zhang <ann.zhuangyanying@huawei.com>
---
 migration/dirtyrate.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++
 migration/dirtyrate.h |   1 +
 2 files changed, 158 insertions(+)

diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index 6baf674..45cfc91 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -10,12 +10,27 @@
  * See the COPYING file in the top-level directory.
  */
 
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "crypto/hash.h"
+#include "crypto/random.h"
+#include "qemu/config-file.h"
+#include "exec/memory.h"
+#include "exec/ramblock.h"
+#include "exec/target_page.h"
+#include "qemu/rcu_queue.h"
+#include "qapi/qapi-commands-migration.h"
+#include "migration.h"
 #include "dirtyrate.h"
 
 static uint64_t sample_pages_per_gigabytes = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
 static struct dirtyrate_statistics dirty_stat;
 CalculatingDirtyRateStage calculating_dirty_rate_stage = CAL_DIRTY_RATE_INIT;
 
+#define RAMBLOCK_FOREACH_MIGRATABLE(block)             \
+        INTERNAL_RAMBLOCK_FOREACH(block)                   \
+        if (!qemu_ram_is_migratable(block)) {} else
+
 static void reset_dirtyrate_stat(void)
 {
     dirty_stat.total_dirty_samples = 0;
@@ -44,6 +59,148 @@ static void update_dirtyrate(int64_t msec)
     dirty_stat.dirty_rate = dirty_rate;
 }
 
+static int get_block_vfn_hash(struct block_dirty_info *info, unsigned long vfn,
+                              uint8_t **md, size_t *hash_len)
+{
+    struct iovec iov_array;
+    int ret = 0;
+    int nkey = 1;
+
+    iov_array.iov_base = info->block_addr +
+                         vfn * DIRTYRATE_SAMPLE_PAGE_SIZE;
+    iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE;
+
+    if (qcrypto_hash_bytesv(QCRYPTO_HASH_ALG_MD5,
+                            &iov_array, nkey,
+                            md, hash_len, NULL) < 0) {
+        ret = -1;
+    }
+
+    return ret;
+}
+
+static int save_block_hash(struct block_dirty_info *info)
+{
+    unsigned long *rand_buf = NULL;
+    unsigned int sample_pages_count;
+    uint8_t *md = NULL;
+    size_t hash_len;
+    int i;
+    int ret = -1;
+
+    sample_pages_count = info->sample_pages_count;
+    /* block size less than one page, return success to skip this block */
+    if (unlikely(info->block_pages == 0 || sample_pages_count == 0)) {
+        ret = 0;
+        goto out;
+    }
+
+    /* use random bytes to pick sample page vfn */
+    rand_buf = g_malloc0_n(sample_pages_count, sizeof(unsigned long));
+    /* DEFAULT_READ_RANDOM_MAX_LIMIT 32M,
+     * can support 4T vm 1024 sample_pages_per_gigabytes
+     */
+    ret = qcrypto_random_bytes((unsigned char *)rand_buf,
+                               sample_pages_count * sizeof(unsigned long),
+                               NULL);
+    if (ret) {
+        ret = -1;
+        goto out;
+    }
+
+    hash_len = qcrypto_hash_digest_len(QCRYPTO_HASH_ALG_MD5);
+    info->hash_result = g_malloc0_n(sample_pages_count, sizeof(uint8_t) * hash_len);
+    info->sample_page_vfn = g_malloc0_n(sample_pages_count, sizeof(unsigned long));
+
+    for (i = 0; i < sample_pages_count; i++) {
+        md = info->hash_result + i * hash_len;
+        info->sample_page_vfn[i] = rand_buf[i] % info->block_pages;
+        ret = get_block_vfn_hash(info, info->sample_page_vfn[i], &md, &hash_len);
+        if (ret < 0) {
+            goto out;
+        }
+    }
+    ret = 0;
+out:
+    g_free(rand_buf);
+    return ret;
+}
+
+static void get_block_dirty_info(RAMBlock *block, struct block_dirty_info *info,
+                                 struct dirtyrate_config *config)
+{
+    uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes;
+
+    /* Right shift 30 bits to calc block size in GB */
+    info->sample_pages_count = (qemu_ram_get_used_length(block) * sample_pages_per_gigabytes) >> 30;
+
+    info->block_pages = qemu_ram_get_used_length(block) >> DIRTYRATE_PAGE_SIZE_SHIFT;
+    info->block_addr = qemu_ram_get_host_addr(block);
+    strcpy(info->idstr, qemu_ram_get_idstr(block));
+}
+
+static struct block_dirty_info *
+alloc_block_dirty_info(int *block_index,
+                       struct block_dirty_info *block_dinfo)
+{
+    struct block_dirty_info *info = NULL;
+    int index = *block_index;
+
+    if (!block_dinfo) {
+        block_dinfo = g_new(struct block_dirty_info, 1);
+        index = 0;
+    } else {
+        block_dinfo = g_realloc(block_dinfo, (index + 1) *
+                                sizeof(struct block_dirty_info));
+        index++;
+    }
+    info = &block_dinfo[index];
+    memset(info, 0, sizeof(struct block_dirty_info));
+
+    *block_index = index;
+    return block_dinfo;
+}
+
+static int ram_block_skip(RAMBlock *block)
+{
+    if (!strstr(qemu_ram_get_idstr(block), "ram-node") &&
+        !strstr(qemu_ram_get_idstr(block), "memdimm")) {
+        if (strcmp(qemu_ram_get_idstr(block), "mach-virt.ram") ||
+            strcmp(block->idstr, "pc.ram")) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+static int record_block_hash_info(struct dirtyrate_config config,
+                                  struct block_dirty_info **block_dinfo, int *block_index)
+{
+    struct block_dirty_info *info = NULL;
+    struct block_dirty_info *dinfo = NULL;
+    RAMBlock *block = NULL;
+    int index = 0;
+
+    RAMBLOCK_FOREACH_MIGRATABLE(block) {
+        if (ram_block_skip(block) < 0) {
+            continue;
+        }
+        dinfo = alloc_block_dirty_info(&index, dinfo);
+        info = &dinfo[index];
+        get_block_dirty_info(block, info, &config);
+        if (save_block_hash(info) < 0) {
+            *block_dinfo = dinfo;
+            *block_index = index;
+            return -1;
+        }
+    }
+
+    *block_dinfo = dinfo;
+    *block_index = index;
+
+    return 0;
+}
 
 static void calculate_dirtyrate(struct dirtyrate_config config, int64_t time)
 {
diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
index 2994535..4d9b3b8 100644
--- a/migration/dirtyrate.h
+++ b/migration/dirtyrate.h
@@ -15,6 +15,7 @@
 
 /* take 256 pages per GB for cal dirty rate */
 #define DIRTYRATE_DEFAULT_SAMPLE_PAGES    256
+#define DIRTYRATE_SAMPLE_PAGE_SIZE      4096
 #define DIRTYRATE_PAGE_SIZE_SHIFT       12
 #define BLOCK_INFO_MAX_LEN              256
 #define PAGE_SIZE_SHIFT                 20
-- 
1.8.3.1