Re: [PATCH 0/3] userfaultfd: allow to forbid unprivileged users

[Paolo Bonzini]

On 14/03/19 00:44, Andrea Arcangeli wrote:
> Then I thought we can add a tristate so an open of /dev/kvm would also
> allow the syscall to make things more user friendly because
> unprivileged containers ideally should have writable mounts done with
> nodev and no matter the privilege they shouldn't ever get an hold on
> the KVM driver (and those who do, like kubevirt, will then just work).

I wouldn't even bother with the KVM special case.  Containers can use
seccomp if they want a fine-grained policy.

(Actually I wouldn't bother with the knob at all; the attack surface of
userfaultfd is infinitesimal compared to the BPF JIT...).

Paolo