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[209.132.183.28]) by mx.google.com with ESMTPS id y53si843661qth.156.2019.03.13.12.12.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 Mar 2019 12:12:30 -0700 (PDT) Received-SPF: pass (google.com: domain of pbonzini@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of pbonzini@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=pbonzini@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A331F3006030; Wed, 13 Mar 2019 19:12:29 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 694536591E; Wed, 13 Mar 2019 19:12:29 +0000 (UTC) Received: from zmail18.collab.prod.int.phx2.redhat.com (zmail18.collab.prod.int.phx2.redhat.com [10.5.83.21]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 09413181A136; Wed, 13 Mar 2019 19:12:29 +0000 (UTC) Date: Wed, 13 Mar 2019 15:12:28 -0400 (EDT) From: Paolo Bonzini To: Andrea Arcangeli Cc: Peter Xu , Mike Kravetz , linux-kernel@vger.kernel.org, Hugh Dickins , Luis Chamberlain , Maxime Coquelin , kvm@vger.kernel.org, Jerome Glisse , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Denis Plotnikov , linux-mm@kvack.org, Marty McFadden , Maya Gokhale , Mike Rapoport , Kees Cook , Mel Gorman , "Kirill A . Shutemov" , linux-fsdevel@vger.kernel.org, "Dr . David Alan Gilbert" , Andrew Morton Message-ID: <1934896481.7779933.1552504348591.JavaMail.zimbra@redhat.com> In-Reply-To: <20190313185230.GH25147@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> Subject: Re: [PATCH 0/3] userfaultfd: allow to forbid unprivileged users MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [93.56.166.5, 10.4.196.11, 10.5.101.130, 10.4.195.27] Thread-Topic: userfaultfd: allow to forbid unprivileged users Thread-Index: 6Xwu07wo6ALzDU1D4rR00nCA3NmgqQ== X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Wed, 13 Mar 2019 19:12:29 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > 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 >