From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 0/3] userfaultfd: allow to forbid unprivileged users
Date: Wed, 13 Mar 2019 15:12:28 -0400 (EDT)
Message-ID: <1934896481.7779933.1552504348591.JavaMail.zimbra@redhat.com>
References: <20190311093701.15734-1-peterx@redhat.com> <58e63635-fc1b-cb53-a4d1-237e6b8b7236@oracle.com> <20190313060023.GD2433@xz-x1> <3714d120-64e3-702e-6eef-4ef253bdb66d@redhat.com> <20190313185230.GH25147@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Cc: Peter Xu <peterx@redhat.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        linux-kernel@vger.kernel.org, Hugh Dickins <hughd@google.com>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Maxime Coquelin <maxime.coquelin@redhat.com>,
        kvm@vger.kernel.org, Jerome Glisse <jglisse@redhat.com>,
        Pavel Emelyanov <xemul@virtuozzo.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Martin Cracauer <cracauer@cons.org>,
        Denis Plotnikov <dplotnikov@virtuozzo.com>, linux-mm@kvack.org,
        Marty McFadden <mcfadden8@llnl.gov>,
        Maya Gokhale <gokhale2@llnl.gov>,
        Mike Rapoport <rppt@linux.vnet.ibm.com>,
        Kees Cook <keescook@chromium.org>,
        Mel Gorman <mgorman@suse.de>,
        "Kirill A . Shutemov" <kirill@shutemov.name>,
        linux-fsdevel@vger.kernel.org,
        "Dr . David Alan Gilbert" <dgilbert@redhat.com>,
To: Andrea Arcangeli <aarcange@redhat.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <20190313185230.GH25147@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org


> On Wed, Mar 13, 2019 at 09:22:31AM +0100, Paolo Bonzini wrote:
> Unless somebody suggests a consistent way to make hugetlbfs "just
> work" (like we could achieve clean with CRIU and KVM), I think Oracle
> will need a one liner change in the Oracle setup to echo into that
> file in addition of running the hugetlbfs mount.

Hi Andrea, can you explain more in detail the risks of enabling
userfaultfd for unprivileged users?

Paolo

> Note that DPDK host bridge process will also need a one liner change
> to do a dummy open/close of /dev/kvm to unblock the syscall.
> 
> Thanks,
> Andrea
>