[PATCH v3 2/3] hw/vfio: drop guest writes to ro regions

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

for vfio regions that are without write permission,
drop guest writes to those regions.

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Xin Zeng <xin.zeng@intel.com>
---
 hw/vfio/common.c     | 8 +++++++-
 hw/vfio/trace-events | 2 +-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 0b3593b3c0..fd6ee1fe3e 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -190,6 +190,11 @@ void vfio_region_write(void *opaque, hwaddr addr,
         uint64_t qword;
     } buf;
 
+    if (!(region->flags & VFIO_REGION_INFO_FLAG_WRITE)) {
+        trace_vfio_region_write(vbasedev->name, region->nr,
+                                   addr, data, size, true);
+        return;
+    }
     switch (size) {
     case 1:
         buf.byte = data;
@@ -215,7 +220,8 @@ void vfio_region_write(void *opaque, hwaddr addr,
                      addr, data, size);
     }
 
-    trace_vfio_region_write(vbasedev->name, region->nr, addr, data, size);
+    trace_vfio_region_write(vbasedev->name, region->nr, addr, data, size,
+                            false);
 
     /*
      * A read or write to a BAR always signals an INTx EOI.  This will
diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
index b1ef55a33f..fb9ff604e6 100644
--- a/hw/vfio/trace-events
+++ b/hw/vfio/trace-events
@@ -91,7 +91,7 @@ vfio_pci_nvlink2_setup_quirk_ssatgt(const char *name, uint64_t tgt, uint64_t siz
 vfio_pci_nvlink2_setup_quirk_lnkspd(const char *name, uint32_t link_speed) "%s link_speed=0x%x"
 
 # common.c
-vfio_region_write(const char *name, int index, uint64_t addr, uint64_t data, unsigned size) " (%s:region%d+0x%"PRIx64", 0x%"PRIx64 ", %d)"
+vfio_region_write(const char *name, int index, uint64_t addr, uint64_t data, unsigned size, bool readonly) " (%s:region%d+0x%"PRIx64", 0x%"PRIx64 ", %d)" " is_readonly_region=%d."
 vfio_region_read(char *name, int index, uint64_t addr, unsigned size, uint64_t data) " (%s:region%d+0x%"PRIx64", %d) = 0x%"PRIx64
 vfio_iommu_map_notify(const char *op, uint64_t iova_start, uint64_t iova_end) "iommu %s @ 0x%"PRIx64" - 0x%"PRIx64
 vfio_listener_region_add_skip(uint64_t start, uint64_t end) "SKIPPING region_add 0x%"PRIx64" - 0x%"PRIx64
-- 
2.17.1