Re: [RFC 00/18] vfio: Adopt iommufd

Jason Gunthorpe
2022-04-25T13:36:20Z

On Mon, Apr 25, 2022 at 11:10:14AM +0100, Daniel P. Berrangé wrote:

> > However, with iommufd there's no reason that QEMU ever needs more than
> > a single instance of /dev/iommufd and we're using per device vfio file
> > descriptors, so it seems like a good time to revisit this.
>
> I assume access to '/dev/iommufd' gives the process somewhat elevated
> privileges, such that you don't want to unconditionally give QEMU
> access to this device ?

I doesn't give much, at worst it allows userspace to allocate kernel
memory and pin pages which can be already be done through all sorts of
other interfaces qemu already has access to..

Jason