From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: Trapping I/O accesses of a driver domain Date: Thu, 10 Nov 2011 18:27:31 -0500 Message-ID: <20111110232727.GA2412@phenom.dumpdata.com> References: <50891.128.2.134.97.1320965847.squirrel@webmail.cs.cmu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <50891.128.2.134.97.1320965847.squirrel@webmail.cs.cmu.edu> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Olatunji Ruwase Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Thu, Nov 10, 2011 at 05:57:27PM -0500, Olatunji Ruwase wrote: > Hi, > I am a graduate student working on dynamic correctness checking of kernel > mode device drivers. I want to detect/trap accesses from a Linux driver > to device accessible locations (e.g ioremap'd, dma_* locations), and > I am exploring the possibility of using Xen for this. I am using x86 PV > Xen-3.3 with a dom0 and driver domU both running linux-2.6.18-xen. For > various reasons HVM Xen is not suitable for my work. Um, why not use something more recent. Like Ubuntu or Fedora Core 16? > > The idea is to use page faults to detect the I/O accesses of the driver > by marking the affected pages not present in the page tables. For > ioremap'd pages, this seems pretty straightforward since the ptes are > marked with _PAGE_IO before they are passed to Xen. And so it seems Not all the time and it is not a requirement. > modifying do_mmu_update () to detect and mark such ptes not present should > work. Is this a reasonable approach ?. What about just checking the MFNs against the ones in the E820 that are in the PCI gap space? > > Detecting accesses to dma mapped (dma_alloc_coherent, dma_map_single) > locations seems more difficult because, as far as I can tell there is no > hypercall informing Xen that the locations are used for I/O. I am probably Right. > misunderstanding how this works and would appreciate clarifications. > > Thank you, > > tunji > > > > > > > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel