[RFC 4/9] hw/vfio/region: Add vfio_region_setup_with_ops() for custom region ops

[<mhonap@nvidia.com>]

From: Manish Honap <mhonap@nvidia.com>

vfio_region_setup() always initializes the region MemoryRegion with
vfio_region_ops. CXL needs custom pread/pwrite ops for the Component
Register shadow region.

Add vfio_region_setup_with_ops() which accepts a const MemoryRegionOps *
parameter. When non-NULL it is passed to memory_region_init_io(); when
NULL the existing vfio_region_ops is used. vfio_region_setup() is
retained unchanged as a thin wrapper for all existing callers.

Signed-off-by: Zhi Wang <zhiw@nvidia.com>
Signed-off-by: Manish Honap <mhonap@nvidia.com>
---
 hw/vfio/region.c      | 15 ++++++++++++---
 hw/vfio/vfio-region.h |  3 +++
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/hw/vfio/region.c b/hw/vfio/region.c
index 0342ca712a..9bbe758d6f 100644
--- a/hw/vfio/region.c
+++ b/hw/vfio/region.c
@@ -228,8 +228,9 @@ static int vfio_setup_region_sparse_mmaps(VFIORegion *region,
     return 0;
 }
 
-int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
-                      int index, const char *name, Error **errp)
+int vfio_region_setup_with_ops(Object *obj, VFIODevice *vbasedev,
+                               VFIORegion *region, int index, const char *name,
+                               Error **errp, const MemoryRegionOps *ops)
 {
     struct vfio_region_info *info = NULL;
     int ret;
@@ -249,7 +250,8 @@ int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
 
     if (region->size) {
         region->mem = g_new0(MemoryRegion, 1);
-        memory_region_init_io(region->mem, obj, &vfio_region_ops,
+        memory_region_init_io(region->mem, obj,
+                              ops ? ops : &vfio_region_ops,
                               region, name, region->size);
 
         if (!vbasedev->no_mmap &&
@@ -273,6 +275,13 @@ int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
     return 0;
 }
 
+int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
+                      int index, const char *name, Error **errp)
+{
+    return vfio_region_setup_with_ops(obj, vbasedev, region, index,
+                                      name, errp, NULL);
+}
+
 static void vfio_subregion_unmap(VFIORegion *region, int index)
 {
     trace_vfio_region_unmap(memory_region_name(&region->mmaps[index].mem),
diff --git a/hw/vfio/vfio-region.h b/hw/vfio/vfio-region.h
index 9b21d4ee5b..84abbec1ec 100644
--- a/hw/vfio/vfio-region.h
+++ b/hw/vfio/vfio-region.h
@@ -39,6 +39,9 @@ uint64_t vfio_region_read(void *opaque,
                           hwaddr addr, unsigned size);
 int vfio_region_setup(Object *obj, VFIODevice *vbasedev, VFIORegion *region,
                       int index, const char *name, Error **errp);
+int vfio_region_setup_with_ops(Object *obj, VFIODevice *vbasedev,
+                               VFIORegion *region, int index, const char *name,
+                               Error **errp, const MemoryRegionOps *ops);
 int vfio_region_mmap(VFIORegion *region);
 void vfio_region_mmaps_set_enabled(VFIORegion *region, bool enabled);
 void vfio_region_unmap(VFIORegion *region);
-- 
2.25.1