[Qemu-devel] [PATCH RFC v3 1/2] memory: allow MemoryRegion's priority field to accept negative values

[Marcel Apfelbaum <marcel.a@redhat.com>]

Priority is used to make visible some subregions by obscuring
the parent MemoryRegion addresses overlapping with the subregion.

By allowing the priority to be negative the opposite can be done:
Allow a subregion to be visible on all the addresses not covered
by the parent MemoryRegion or other subregions.

Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com>
---
 include/exec/memory.h | 6 +++---
 memory.c              | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index ebe0d24..6995087 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -153,7 +153,7 @@ struct MemoryRegion {
     bool flush_coalesced_mmio;
     MemoryRegion *alias;
     hwaddr alias_offset;
-    unsigned priority;
+    int priority;
     bool may_overlap;
     QTAILQ_HEAD(subregions, MemoryRegion) subregions;
     QTAILQ_ENTRY(MemoryRegion) subregions_link;
@@ -193,7 +193,7 @@ struct MemoryListener {
     void (*coalesced_mmio_del)(MemoryListener *listener, MemoryRegionSection *section,
                                hwaddr addr, hwaddr len);
     /* Lower = earlier (during add), later (during del) */
-    unsigned priority;
+    int priority;
     AddressSpace *address_space_filter;
     QTAILQ_ENTRY(MemoryListener) link;
 };
@@ -779,7 +779,7 @@ void memory_region_add_subregion(MemoryRegion *mr,
 void memory_region_add_subregion_overlap(MemoryRegion *mr,
                                          hwaddr offset,
                                          MemoryRegion *subregion,
-                                         unsigned priority);
+                                         int priority);
 
 /**
  * memory_region_get_ram_addr: Get the ram address associated with a memory
diff --git a/memory.c b/memory.c
index 5a10fd0..984a3dc 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;
-- 
1.8.3.1