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?
>
>
> > + }
> > + 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. */
