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