[PATCH v4 3/3] hw/vfio: let read-only flag take effect for mmap'd regions

[Yan Zhao <yan.y.zhao@intel.com>]

along side setting host page table to be read-only, the memory regions
are also required to be read-only, so that when guest writes to the
read-only & mmap'd regions, vmexits would happen and region write handlers
are called.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Xin Zeng <xin.zeng@intel.com>
---
 hw/vfio/common.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index b6956a8098..0049e97c34 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -979,6 +979,10 @@ int vfio_region_mmap(VFIORegion *region)
                                           name, region->mmaps[i].size,
                                           region->mmaps[i].mmap);
         g_free(name);
+
+        if (!(region->flags & VFIO_REGION_INFO_FLAG_WRITE)) {
+            memory_region_set_readonly(&region->mmaps[i].mem, true);
+        }
         memory_region_add_subregion(region->mem, region->mmaps[i].offset,
                                     &region->mmaps[i].mem);
 
-- 
2.17.1