migration: Add an ability to ignore shared RAM blocks

If ignore-shared capability is set then skip shared RAMBlocks during the
RAM migration.
Also, move qemu_ram_foreach_migratable_block (and rename) to the
migration code, because it requires access to the migration capabilities.

Signed-off-by: Yury Kotov <yury-kotov@yandex-team.ru>
Message-Id: <20190215174548.2630-4-yury-kotov@yandex-team.ru>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

exec.c

@@ -3985,25 +3985,6 @@ int qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque)
     return ret;
 }
 
-int qemu_ram_foreach_migratable_block(RAMBlockIterFunc func, void *opaque)
-{
-    RAMBlock *block;
-    int ret = 0;
-
-    rcu_read_lock();
-    RAMBLOCK_FOREACH(block) {
-        if (!qemu_ram_is_migratable(block)) {
-            continue;
-        }
-        ret = func(block, opaque);
-        if (ret) {
-            break;
-        }
-    }
-    rcu_read_unlock();
-    return ret;
-}
-
 /*
  * Unmap pages of memory from start to start+length such that
  * they a) read as 0, b) Trigger whatever fault mechanism

include/exec/cpu-common.h

@@ -122,7 +122,6 @@ extern struct MemoryRegion io_mem_notdirty;
 typedef int (RAMBlockIterFunc)(RAMBlock *rb, void *opaque);
 
 int qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque);
-int qemu_ram_foreach_migratable_block(RAMBlockIterFunc func, void *opaque);
 int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length);
 
 #endif

migration/migration.h

@@ -306,8 +306,10 @@ void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value);
 void dirty_bitmap_mig_before_vm_start(void);
 void init_dirty_bitmap_incoming_migration(void);
 
+int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque);
+
 #define qemu_ram_foreach_block \
-  #warning "Use qemu_ram_foreach_block_migratable in migration code"
+  #warning "Use foreach_not_ignored_block in migration code"
 
 void migration_make_urgent_request(void);
 void migration_consume_urgent_request(void);

migration/postcopy-ram.c

@@ -374,7 +374,7 @@ bool postcopy_ram_supported_by_host(MigrationIncomingState *mis)
     }
 
     /* We don't support postcopy with shared RAM yet */
-    if (qemu_ram_foreach_migratable_block(test_ramblock_postcopiable, NULL)) {
+    if (foreach_not_ignored_block(test_ramblock_postcopiable, NULL)) {
         goto out;
     }
 
@@ -508,7 +508,7 @@ static int cleanup_range(RAMBlock *rb, void *opaque)
  */
 int postcopy_ram_incoming_init(MigrationIncomingState *mis)
 {
-    if (qemu_ram_foreach_migratable_block(init_range, NULL)) {
+    if (foreach_not_ignored_block(init_range, NULL)) {
         return -1;
     }
 
@@ -550,7 +550,7 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis)
             return -1;
         }
 
-        if (qemu_ram_foreach_migratable_block(cleanup_range, mis)) {
+        if (foreach_not_ignored_block(cleanup_range, mis)) {
             return -1;
         }
 
@@ -617,7 +617,7 @@ static int nhp_range(RAMBlock *rb, void *opaque)
  */
 int postcopy_ram_prepare_discard(MigrationIncomingState *mis)
 {
-    if (qemu_ram_foreach_migratable_block(nhp_range, mis)) {
+    if (foreach_not_ignored_block(nhp_range, mis)) {
         return -1;
     }
 
@@ -628,7 +628,7 @@ int postcopy_ram_prepare_discard(MigrationIncomingState *mis)
 
 /*
  * Mark the given area of RAM as requiring notification to unwritten areas
- * Used as a  callback on qemu_ram_foreach_migratable_block.
+ * Used as a  callback on foreach_not_ignored_block.
  *   host_addr: Base of area to mark
  *   offset: Offset in the whole ram arena
  *   length: Length of the section
@@ -1122,7 +1122,7 @@ int postcopy_ram_enable_notify(MigrationIncomingState *mis)
     mis->have_fault_thread = true;
 
     /* Mark so that we get notified of accesses to unwritten areas */
-    if (qemu_ram_foreach_migratable_block(ram_block_enable_notify, mis)) {
+    if (foreach_not_ignored_block(ram_block_enable_notify, mis)) {
         error_report("ram_block_enable_notify failed");
         return -1;
     }