[Qemu-devel] [RFC PATCH v2 3/6] memory: add memory_region_to_address()

[Scott Wood <scottwood@freescale.com>]

This is useful for when a user of the memory region API needs to
communicate the absolute bus address to something outside QEMU
(in particular, KVM).

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
TODO: Use add/del memory listeners later in the patchset, which would
eliminate the need for this patch.
---
 include/exec/memory.h |    9 +++++++++
 memory.c              |   38 ++++++++++++++++++++++++++++++++++----
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 2322732..b800391 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -892,6 +892,15 @@ void *address_space_map(AddressSpace *as, hwaddr addr,
 void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
                          int is_write, hwaddr access_len);
 
+/* memory_region_to_address: Find the full address of the start of the
+ *      given #MemoryRegion, ignoring aliases.  There is no guarantee
+ *      that the #MemoryRegion is actually visible at this address, if
+ *      there are overlapping regions.
+ *
+ * @mr: #MemoryRegion being queried
+ * @asp: if non-NULL, returns the #AddressSpace @mr is mapped in, if any
+ */
+hwaddr memory_region_to_address(MemoryRegion *mr, AddressSpace **asp);
 
 #endif
 
diff --git a/memory.c b/memory.c
index 75ca281..5d3b13d 100644
--- a/memory.c
+++ b/memory.c
@@ -453,21 +453,51 @@ const IORangeOps memory_region_iorange_ops = {
     .destructor = memory_region_iorange_destructor,
 };
 
-static AddressSpace *memory_region_to_address_space(MemoryRegion *mr)
+static AddressSpace *memory_region_root_to_address_space(MemoryRegion *mr)
 {
     AddressSpace *as;
 
-    while (mr->parent) {
-        mr = mr->parent;
-    }
     QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
         if (mr == as->root) {
             return as;
         }
     }
+
+    return NULL;
+}
+
+static AddressSpace *memory_region_to_address_space(MemoryRegion *mr)
+{
+    AddressSpace *as;
+
+    while (mr->parent) {
+        mr = mr->parent;
+    }
+
+    as = memory_region_root_to_address_space(mr);
+    if (as) {
+        return as;
+    }
+
     abort();
 }
 
+hwaddr memory_region_to_address(MemoryRegion *mr, AddressSpace **asp)
+{
+    hwaddr addr = mr->addr;
+
+    while (mr->parent) {
+        mr = mr->parent;
+        addr += mr->addr;
+    }
+
+    if (asp) {
+        *asp = memory_region_root_to_address_space(mr);
+    }
+
+    return addr;
+}
+
 /* Render a memory region into the global view.  Ranges in @view obscure
  * ranges in @mr.
  */
-- 
1.7.10.4