On 25/09/20 19:12, Sean Christopherson wrote: >> Do we actually want to prevent *all* ioctls? E.g. when 'vm bugged' >> condition is triggered userspace may want to extract some information to >> assist debugging but even things like KVM_GET_[S]REGS will just return >> -EIO. I'm not sure it is generally safe to enable *everything* (except >> for KVM_RUN which should definitely be forbidden) so maybe your approach >> is preferable. > > The answer to this probably depends on the answer to the first question of > when it's appropriate to use KVM_BUG(). E.g. if we limit usage to fatal or > dangrous cases, then blocking all ioctls() is probably the right thing do do. I think usage should be limited to dangerous cases, basically WARN_ON level. However I agree with Vitaly that KVM_GET_* should be allowed. The other question is whether to return -EIO or KVM_EXIT_INTERNAL_ERROR. The latter is more likely to be handled already by userspace. Paolo
