Re: [PATCH v4 2/9] vfio-iommufd: Create iommufd_access for noiommu devices

Jason Gunthorpe
2023-05-02T18:12:20Z

On Sat, Apr 29, 2023 at 12:07:24AM +0800, Yi Liu wrote:
> > The emulated stuff is for mdev only, it should not be confused with
> > no-iommu
>
> hmmm. I guess the confusion is due to the reuse of
> vfio_iommufd_emulated_bind().

This is probabl y not a good direction

> > Eg if you had a no_iommu_access value to store the access it would be
> > fine and could serve as the 'this is no_iommu' flag
>
> So this no_iommu_access shall be created per iommufd bind, and call the
> iommufd_access_create() with iommufd_access_ops. is it? If so, this is
> not 100% the same with no_iommu flag as this flag is static after device
> registration.

Something like that, yes

I don't think it is any real difference with the current flag, both
are determined at the first ioctl when the iommufd is presented and
both would state permanently until the fd close

Jason