From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: Re: [PATCH 01/12] Security: Add CAP_COMPROMISE_KERNEL Date: Tue, 19 Mar 2013 21:18:23 -0600 Message-ID: <1363749503.24132.482.camel@bling.home> References: <3pfl8u1ugprwkcs5xmtjth3l.1363742692541@email.android.com> <51492379.3090302@zytor.com> <51492828.5070803@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51492828.5070803-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "H. Peter Anvin" Cc: Matthew Garrett , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-efi@vger.kernel.org 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