1 files changed, 62 insertions, 0 deletions
diff --git a/include/exec/memory-internal.h b/include/exec/memory-internal.h
index 647e9bd5c4..98d82964cc 100644
--- a/include/exec/memory-internal.h
+++ b/include/exec/memory-internal.h
@@ -39,5 +39,67 @@ void mtree_print_dispatch(fprintf_function mon, void *f,
                           struct AddressSpaceDispatch *d,
                           MemoryRegion *root);
 
+/* Opaque struct for passing info from memory_notdirty_write_prepare()
+ * to memory_notdirty_write_complete(). Callers should treat all fields
+ * as private, with the exception of @active.
+ *
+ * @active is a field which is not touched by either the prepare or
+ * complete functions, but which the caller can use if it wishes to
+ * track whether it has called prepare for this struct and so needs
+ * to later call the complete function.
+ */
+typedef struct {
+    CPUState *cpu;
+    ram_addr_t ram_addr;
+    vaddr mem_vaddr;
+    unsigned size;
+    bool locked;
+    bool active;
+} NotDirtyInfo;
+
+/**
+ * memory_notdirty_write_prepare: call before writing to non-dirty memory
+ * @ndi: pointer to opaque NotDirtyInfo struct
+ * @cpu: CPU doing the write
+ * @mem_vaddr: virtual address of write
+ * @ram_addr: the ram address of the write
+ * @size: size of write in bytes
+ *
+ * Any code which writes to the host memory corresponding to
+ * guest RAM which has been marked as NOTDIRTY must wrap those
+ * writes in calls to memory_notdirty_write_prepare() and
+ * memory_notdirty_write_complete():
+ *
+ *  NotDirtyInfo ndi;
+ *  memory_notdirty_write_prepare(&ndi, ....);
+ *  ... perform write here ...
+ *  memory_notdirty_write_complete(&ndi);
+ *
+ * These calls will ensure that we flush any TCG translated code for
+ * the memory being written, update the dirty bits and (if possible)
+ * remove the slowpath callback for writing to the memory.
+ *
+ * This must only be called if we are using TCG; it will assert otherwise.
+ *
+ * We may take a lock in the prepare call, so callers must ensure that
+ * they don't exit (via longjump or otherwise) without calling complete.
+ *
+ * This call must only be made inside an RCU critical section.
+ * (Note that while we're executing a TCG TB we're always in an
+ * RCU critical section, which is likely to be the case for callers
+ * of these functions.)
+ */
+void memory_notdirty_write_prepare(NotDirtyInfo *ndi,
+                                   CPUState *cpu,
+                                   vaddr mem_vaddr,
+                                   ram_addr_t ram_addr,
+                                   unsigned size);
+/**
+ * memory_notdirty_write_complete: finish write to non-dirty memory
+ * @ndi: pointer to the opaque NotDirtyInfo struct which was initialized
+ * by memory_not_dirty_write_prepare().
+ */
+void memory_notdirty_write_complete(NotDirtyInfo *ndi);
+
 #endif
 #endif