On 10/7/25 06:50, Kasireddy, Vivek wrote:
Hi Cedric,
Subject: Re: [PATCH v1 4/7] vfio/region: Add a helper to get region index from
memory region
Hello Vivek,
On 10/4/25 01:35, Vivek Kasireddy wrote:
Having a way to figure out the region index (or bar) associated
with a memory region is helpful in various scenarios. For example,
this capability can be useful in retrieving the region info needed
for mapping a part of a VFIO region or creating a dmabuf.
Cc: Alex Williamson <[email protected]>
Cc: Cédric Le Goater <[email protected]>
Signed-off-by: Vivek Kasireddy <[email protected]>
---
hw/vfio/region.c | 14 ++++++++++++++
include/hw/vfio/vfio-device.h | 2 ++
2 files changed, 16 insertions(+)
diff --git a/hw/vfio/region.c b/hw/vfio/region.c
index b165ab0b93..8837afc97f 100644
--- a/hw/vfio/region.c
+++ b/hw/vfio/region.c
@@ -398,3 +398,17 @@ void vfio_region_mmaps_set_enabled(VFIORegion
*region, bool enabled)
trace_vfio_region_mmaps_set_enabled(memory_region_name(region-
mem),
enabled);
}
+
+int vfio_get_region_index_from_mr(MemoryRegion *mr)
+{
+ VFIORegion *region = mr->opaque;
+
+ if (mr->ops != &vfio_region_ops) {
+ mr = mr->container;
May be start the routine with :
while (mr->container) {
mr = mr->container;
}
Ok, makes sense.
+ if (mr->ops != &vfio_region_ops) {
+ return -1;
I think I would prefer returning a 'VFIORegion *' which should be
NULL in case of error. Looks cleaner.
Given that VFIORegion type is no longer exposed to other subsystems,
I am guessing you meant adding two helpers: internal helper that would
return VFIORegion * and an external routine that would call the internal
helper and return region->nr?
After seeing how vfio_get_region_index_from_mr() was used in
vfio_dmabuf_mmap(), I think it is fine to keep your proposal
unchanged. we can refine it later.
Thanks,
C.
+ }
+ region = mr->opaque;
+ }
+ return region->nr;
+}
diff --git a/include/hw/vfio/vfio-device.h b/include/hw/vfio/vfio-device.h
index 7e9aed6d3c..bdb106c937 100644
--- a/include/hw/vfio/vfio-device.h
+++ b/include/hw/vfio/vfio-device.h
@@ -277,6 +277,8 @@ bool vfio_device_has_region_cap(VFIODevice
*vbasedev, int region, uint16_t cap_t
int vfio_device_get_irq_info(VFIODevice *vbasedev, int index,
struct vfio_irq_info *info);
+
+int vfio_get_region_index_from_mr(MemoryRegion *mr);
Please add documentation.
Sure, will do.
Thanks,
Vivek
Thanks,
C.
#endif
/* Returns 0 on success, or a negative errno. */
