patch 1 modifies handler of ram device memory regions to drop guest writes
to read-only ram device memory regions

patch 2 modifies handler of non-mmap'd read-only vfio regions to drop guest
writes to those regions 

patch 3 set read-only flag to mmap'd read-only vfio regions, so that guest
writes to those regions would be trapped.
without patch 1, host qemu would then crash on guest write to those read-only
regions.
with patch 1, host qemu would drop the writes.

Changelog:
v3:
-refreshed and Cc Stefan for reviewing of tracing part

v2:
-split one big patches into smaller ones (Philippe)
-modify existing trace to record guest writes to read-only memory (Alex)
-modify vfio_region_write() to drop guest writes to non-mmap'd read-only
 region (Alex)

Yan Zhao (3):
  memory: drop guest writes to read-only ram device regions
  hw/vfio: drop guest writes to ro regions
  hw/vfio: let read-only flag take effect for mmap'd regions

 hw/vfio/common.c     | 12 +++++++++++-
 hw/vfio/trace-events |  2 +-
 memory.c             |  6 +++++-
 trace-events         |  2 +-
 4 files changed, 18 insertions(+), 4 deletions(-)

-- 
2.17.1