RE: [PATCH v5 15/19] vfio: Add cdev for vfio_device

Liu, Yi L
2023-02-28T03:48:00Z

> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Tuesday, February 28, 2023 2:56 AM
>
> On Mon, Feb 27, 2023 at 03:11:31AM -0800, Yi Liu wrote:
> > diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
> > index a8f544629467..169762316513 100644
> > --- a/drivers/vfio/Kconfig
> > +++ b/drivers/vfio/Kconfig
> > @@ -12,6 +12,18 @@ menuconfig VFIO
> > If you don't know what to do here, say N.
> >
> > if VFIO
> > +config VFIO_DEVICE_CDEV
> > + bool "Support for the VFIO cdev /dev/vfio/devices/vfioX"
> > + depends on IOMMUFD && (X86 || S390 || ARM || ARM64)
>
> We don't need to propogate this arch detection stuff, at worst it
> should be in iommufd kconfig if it is really needed.

Ok. this makes sense as cdev's real dependency is iommufd.

Btw. Also no need for the below stuff. Is it? just select CDEV if !VFIO_GROUP.
right?

select VFIO_DEVICE_CDEV if !VFIO_GROUP && (X86 || S390 || ARM || ARM64)

> Also that other thread shows that vfio doesn't work on ARM because we
> can never take ownership of a device due to arm iommu

It's interesting. May you share the link of this thread?:-)

Regards,
Yi Liu