memory: Change MemoryRegion priorities from unsigned to signed

When memory regions overlap, priority can be used to specify
which of them takes priority. By making the priority values signed
rather than unsigned, we make it more convenient to implement
a situation where one "background" region should appear only
where no other region exists: rather than having to explicitly
specify a high priority for all the other regions, we can let them take
the default (zero) priority and specify a negative priority for the
background region.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/memory.c b/memory.c
index 5a10fd0bde..f49d31ae72 100644
--- a/memory.c
+++ b/memory.c
@@ -1473,7 +1473,7 @@ void memory_region_add_subregion(MemoryRegion *mr,
 void memory_region_add_subregion_overlap(MemoryRegion *mr,
                                          hwaddr offset,
                                          MemoryRegion *subregion,
-                                         unsigned priority)
+                                         int priority)
 {
     subregion->may_overlap = true;
     subregion->priority = priority;
@@ -1506,7 +1506,7 @@ void memory_region_set_enabled(MemoryRegion *mr, bool enabled)
 void memory_region_set_address(MemoryRegion *mr, hwaddr addr)
 {
     MemoryRegion *parent = mr->parent;
-    unsigned priority = mr->priority;
+    int priority = mr->priority;
     bool may_overlap = mr->may_overlap;
 
     if (addr == mr->addr || !parent) {