memory: Extract memory_region_msync() from memory_region_writeback()

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20200508062456.23344-3-philmd@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

2 files changed, 20 insertions, 3 deletions

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 1b7cfdd5b6..3e00cdbbfa 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -1473,8 +1473,19 @@ void *memory_region_get_ram_ptr(MemoryRegion *mr);
  */
 void memory_region_ram_resize(MemoryRegion *mr, ram_addr_t newsize,
                               Error **errp);
+
+/**
+ * memory_region_msync: Synchronize selected address range of
+ * a memory mapped region
+ *
+ * @mr: the memory region to be msync
+ * @addr: the initial address of the range to be sync
+ * @size: the size of the range to be sync
+ */
+void memory_region_msync(MemoryRegion *mr, hwaddr addr, hwaddr size);
+
 /**
- * memory_region_writeback: Trigger cache writeback or msync for
+ * memory_region_writeback: Trigger cache writeback for
  * selected address range
  *
  * @mr: the memory region to be updated
diff --git a/memory.c b/memory.c
index bb84334e1e..93febe4759 100644
--- a/memory.c
+++ b/memory.c
@@ -2197,6 +2197,12 @@ void memory_region_ram_resize(MemoryRegion *mr, ram_addr_t newsize, Error **errp
     qemu_ram_resize(mr->ram_block, newsize, errp);
 }
 
+void memory_region_msync(MemoryRegion *mr, hwaddr addr, hwaddr size)
+{
+    if (mr->ram_block) {
+        qemu_ram_writeback(mr->ram_block, addr, size);
+    }
+}
 
 void memory_region_writeback(MemoryRegion *mr, hwaddr addr, hwaddr size)
 {
@@ -2204,8 +2210,8 @@ void memory_region_writeback(MemoryRegion *mr, hwaddr addr, hwaddr size)
      * Might be extended case needed to cover
      * different types of memory regions
      */
-    if (mr->ram_block && mr->dirty_log_mask) {
-        qemu_ram_writeback(mr->ram_block, addr, size);
+    if (mr->dirty_log_mask) {
+        memory_region_msync(mr, addr, size);
     }
 }