[RFC PATCH v1 11/26] migration: Refactor precopy ram loading code

[Fabiano Rosas]

From: Nikolay Borisov <nborisov@suse.com>

To facilitate the implementation of the 'fixed-ram' migration restore,
factor out the code responsible for parsing the ramblocks
headers. This also makes ram_load_precopy easier to comprehend.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 migration/ram.c | 142 +++++++++++++++++++++++++++---------------------
 1 file changed, 80 insertions(+), 62 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 56f0f782c8..5c085d6154 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -4319,6 +4319,83 @@ void colo_flush_ram_cache(void)
     trace_colo_flush_ram_cache_end();
 }
 
+static int parse_ramblock(QEMUFile *f, RAMBlock *block, ram_addr_t length)
+{
+    int ret = 0;
+    /* ADVISE is earlier, it shows the source has the postcopy capability on */
+    bool postcopy_advised = migration_incoming_postcopy_advised();
+
+    assert(block);
+
+    if (!qemu_ram_is_migratable(block)) {
+        error_report("block %s should not be migrated !", block->idstr);
+        ret = -EINVAL;
+    }
+
+    if (length != block->used_length) {
+        Error *local_err = NULL;
+
+        ret = qemu_ram_resize(block, length, &local_err);
+        if (local_err) {
+            error_report_err(local_err);
+        }
+    }
+    /* For postcopy we need to check hugepage sizes match */
+    if (postcopy_advised && migrate_postcopy_ram() &&
+        block->page_size != qemu_host_page_size) {
+        uint64_t remote_page_size = qemu_get_be64(f);
+        if (remote_page_size != block->page_size) {
+            error_report("Mismatched RAM page size %s "
+                         "(local) %zd != %" PRId64, block->idstr,
+                         block->page_size, remote_page_size);
+            ret = -EINVAL;
+        }
+    }
+    if (migrate_ignore_shared()) {
+        hwaddr addr = qemu_get_be64(f);
+        if (ramblock_is_ignored(block) &&
+            block->mr->addr != addr) {
+            error_report("Mismatched GPAs for block %s "
+                         "%" PRId64 "!= %" PRId64, block->idstr,
+                         (uint64_t)addr,
+                         (uint64_t)block->mr->addr);
+            ret = -EINVAL;
+        }
+    }
+    ram_control_load_hook(f, RAM_CONTROL_BLOCK_REG, block->idstr);
+
+    return ret;
+}
+
+static int parse_ramblocks(QEMUFile *f, ram_addr_t total_ram_bytes)
+{
+    int ret = 0;
+
+    /* Synchronize RAM block list */
+    while (!ret && total_ram_bytes) {
+        char id[256];
+        RAMBlock *block;
+        ram_addr_t length;
+        int 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) {
+            ret = parse_ramblock(f, block, length);
+        } else {
+            error_report("Unknown ramblock \"%s\", cannot accept "
+                         "migration", id);
+            ret = -EINVAL;
+        }
+        total_ram_bytes -= length;
+    }
+
+    return ret;
+}
+
 /**
  * ram_load_precopy: load pages in precopy case
  *
@@ -4333,14 +4410,13 @@ static int ram_load_precopy(QEMUFile *f)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
     int flags = 0, ret = 0, invalid_flags = 0, len = 0, i = 0;
-    /* ADVISE is earlier, it shows the source has the postcopy capability on */
-    bool postcopy_advised = migration_incoming_postcopy_advised();
+
     if (!migrate_use_compression()) {
         invalid_flags |= RAM_SAVE_FLAG_COMPRESS_PAGE;
     }
 
     while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) {
-        ram_addr_t addr, total_ram_bytes;
+        ram_addr_t addr;
         void *host = NULL, *host_bak = NULL;
         uint8_t ch;
 
@@ -4411,65 +4487,7 @@ static int ram_load_precopy(QEMUFile *f)
 
         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 && !qemu_ram_is_migratable(block)) {
-                    error_report("block %s should not be migrated !", id);
-                    ret = -EINVAL;
-                } else if (block) {
-                    if (length != block->used_length) {
-                        Error *local_err = NULL;
-
-                        ret = qemu_ram_resize(block, length,
-                                              &local_err);
-                        if (local_err) {
-                            error_report_err(local_err);
-                        }
-                    }
-                    /* For postcopy we need to check hugepage sizes match */
-                    if (postcopy_advised && migrate_postcopy_ram() &&
-                        block->page_size != qemu_host_page_size) {
-                        uint64_t remote_page_size = qemu_get_be64(f);
-                        if (remote_page_size != block->page_size) {
-                            error_report("Mismatched RAM page size %s "
-                                         "(local) %zd != %" PRId64,
-                                         id, block->page_size,
-                                         remote_page_size);
-                            ret = -EINVAL;
-                        }
-                    }
-                    if (migrate_ignore_shared()) {
-                        hwaddr addr = qemu_get_be64(f);
-                        if (ramblock_is_ignored(block) &&
-                            block->mr->addr != addr) {
-                            error_report("Mismatched GPAs for block %s "
-                                         "%" PRId64 "!= %" PRId64,
-                                         id, (uint64_t)addr,
-                                         (uint64_t)block->mr->addr);
-                            ret = -EINVAL;
-                        }
-                    }
-                    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;
-            }
+            ret = parse_ramblocks(f, addr);
             break;
 
         case RAM_SAVE_FLAG_ZERO:
-- 
2.35.3