Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757964Ab3CTDSd (ORCPT ); Tue, 19 Mar 2013 23:18:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54696 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750910Ab3CTDSb (ORCPT ); Tue, 19 Mar 2013 23:18:31 -0400 Message-ID: <1363749503.24132.482.camel@bling.home> Subject: Re: [PATCH 01/12] Security: Add CAP_COMPROMISE_KERNEL From: Alex Williamson To: "H. Peter Anvin" Cc: Matthew Garrett , "linux-kernel@vger.kernel.org" , "linux-security-module@vger.kernel.org" , "linux-efi@vger.kernel.org" , "kexec@lists.infradead.org" , "linux-pci@vger.kernel.org" Date: Tue, 19 Mar 2013 21:18:23 -0600 In-Reply-To: <51492828.5070803@zytor.com> References: <3pfl8u1ugprwkcs5xmtjth3l.1363742692541@email.android.com> <51492379.3090302@zytor.com> <51492828.5070803@zytor.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1287 Lines: 34 On Tue, 2013-03-19 at 20:08 -0700, H. Peter Anvin wrote: > On 03/19/2013 07:48 PM, H. Peter Anvin wrote: > > On 03/19/2013 06:28 PM, Matthew Garrett wrote: > >> Mm. The question is whether we can reliably determine the ranges a > device should be able to access without having to trust userspace > (and, ideally, without having to worry about whether iommu vendors > have done their job). It's pretty important for PCI passthrough, so we > do need to care. > > > > It is actually very simple: the device should be able to DMA into/out of: > > > > 1. pinned pages > > 2. owned by the process controlling the device > > > > ... and nothing else. > > > > The "pinning" process needs to involve a call to the kernel to process > the page for DMA (pinning the page and opening it in the iommu) and > return a transaction address, of course. > > I think we have the interface for that in vfio, but I haven't followed > that work. Yes, vfio does this and is meant to provide a secure-boot-friendly PCI passthrough interface. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/