From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [net-next PATCH v1 1/3] net: sched: af_packet support for direct ring access Date: Tue, 07 Oct 2014 11:43:41 -0400 (EDT) Message-ID: <20141007.114341.1417644866461362364.davem@davemloft.net> References: <20141006000629.32055.2295.stgit@nitbit.x32> <063D6719AE5E284EB5DD2968C1650D6D174C5C35@AcuExch.aculab.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: willemb@google.com, john.fastabend@gmail.com, dborkman@redhat.com, fw@strlen.de, gerlitz.or@gmail.com, hannes@stressinduktion.org, netdev@vger.kernel.org, john.ronciak@intel.com, amirv@mellanox.com, eric.dumazet@gmail.com, danny.zhou@intel.com To: David.Laight@ACULAB.COM Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:45796 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753478AbaJGPno (ORCPT ); Tue, 7 Oct 2014 11:43:44 -0400 In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D174C5C35@AcuExch.aculab.com> Sender: netdev-owner@vger.kernel.org List-ID: From: David Laight Date: Tue, 7 Oct 2014 09:27:03 +0000 > That is (probably) the only scheme that stops the application > accessing random parts of physical memory. I don't know where this claim keeps coming from, it's false. The application has to attach memory to the ring, and then the ring can only refer to that memory for the duration of the session. There is no way that the user can program the address field of the descriptors to point at arbitrary physical memory locations. There is protection and control.