memory: Pass mr into snapshot_and_clear_dirty

Also we change the 2nd parameter of it to be the relative offset
within the memory region. This is to be used in follow up patches.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Reviewed-by: NJuan Quintela <quintela@redhat.com>
Message-Id: <20190603065056.25211-6-peterx@redhat.com>
Signed-off-by: NJuan Quintela <quintela@redhat.com>

exec.c

@@ -1390,9 +1390,10 @@ bool cpu_physical_memory_test_and_clear_dirty(ram_addr_t start,
 }
 
 DirtyBitmapSnapshot *cpu_physical_memory_snapshot_and_clear_dirty
-     (ram_addr_t start, ram_addr_t length, unsigned client)
+    (MemoryRegion *mr, hwaddr offset, hwaddr length, unsigned client)
 {
     DirtyMemoryBlocks *blocks;
+    ram_addr_t start = memory_region_get_ram_addr(mr) + offset;
     unsigned long align = 1UL << (TARGET_PAGE_BITS + BITS_PER_LEVEL);
     ram_addr_t first = QEMU_ALIGN_DOWN(start, align);
     ram_addr_t last  = QEMU_ALIGN_UP(start + length, align);

include/exec/ram_addr.h

@@ -404,7 +404,7 @@ bool cpu_physical_memory_test_and_clear_dirty(ram_addr_t start,
                                               unsigned client);
 
 DirtyBitmapSnapshot *cpu_physical_memory_snapshot_and_clear_dirty
-    (ram_addr_t start, ram_addr_t length, unsigned client);
+    (MemoryRegion *mr, hwaddr offset, hwaddr length, unsigned client);
 
 bool cpu_physical_memory_snapshot_get_dirty(DirtyBitmapSnapshot *snap,
                                             ram_addr_t start,

memory.c

@@ -2071,8 +2071,7 @@ DirtyBitmapSnapshot *memory_region_snapshot_and_clear_dirty(MemoryRegion *mr,
 {
     assert(mr->ram_block);
     memory_region_sync_dirty_bitmap(mr);
-    return cpu_physical_memory_snapshot_and_clear_dirty(
-                memory_region_get_ram_addr(mr) + addr, size, client);
+    return cpu_physical_memory_snapshot_and_clear_dirty(mr, addr, size, client);
 }
 
 bool memory_region_snapshot_get_dirty(MemoryRegion *mr, DirtyBitmapSnapshot *snap,