Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758237Ab3J2QJB (ORCPT ); Tue, 29 Oct 2013 12:09:01 -0400 Received: from host217-34-137-81.in-addr.btopenworld.com ([217.34.137.81]:56196 "EHLO external.sentinel2" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754001Ab3J2QJA (ORCPT ); Tue, 29 Oct 2013 12:09:00 -0400 X-Greylist: delayed 543 seconds by postgrey-1.27 at vger.kernel.org; Tue, 29 Oct 2013 12:09:00 EDT MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 29 Oct 2013 15:59:53 +0000 From: Gordan Bobic To: Konrad Rzeszutek Wilk Cc: Jan Beulich , xen-devel , , , , David Vrabel , , Bjorn Helgaas , Subject: Re: [Xen-devel] [v1 1/2] xen/p2m: Create identity mappings for PFNs beyound E820 and PCI BARs In-Reply-To: <20131029151129.GA20984@phenom.dumpdata.com> References: "\"<1382713401-4882-1-git-send-email-konrad.wilk@oracle.com> <1382713401-4882-2-git-send-email-konrad.wilk@oracle.com> <20131028165837.GH4353@phenom.dumpdata.com> <526F7E9202000078000FD7A6@nat28.tlf.novell.com>" <20131029144559.GI20487@phenom.dumpdata.com>" <526FDA6102000078000FDAE2@nat28.tlf.novell.com> <20131029151129.GA20984@phenom.dumpdata.com> Message-ID: User-Agent: Roundcube Webmail/0.4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2473 Lines: 58 On Tue, 29 Oct 2013 11:11:29 -0400, Konrad Rzeszutek Wilk wrote: > On Tue, Oct 29, 2013 at 02:55:13PM +0000, Jan Beulich wrote: >> >>> On 29.10.13 at 15:45, Konrad Rzeszutek Wilk >> wrote: >> > On Tue, Oct 29, 2013 at 08:23:30AM +0000, Jan Beulich wrote: >> >> >>> On 28.10.13 at 17:58, Konrad Rzeszutek Wilk >> wrote: >> >> > On Fri, Oct 25, 2013 at 04:08:19PM -0600, Bjorn Helgaas wrote: >> >> >> If you can look at PCI host bridge apertures instead of BARs, >> that >> >> >> would solve both problems. Reassigning those apertures is >> >> >> theoretically possible but is not even a gleam in our eyes >> yet. >> >> > >> >> > I think I have to have both (BARs and host bridge >> apertures) as when >> >> > we do PCI passthrough to a guest - we might do it without a >> bridge. >> >> >> >> Why? Aren't the host bridge ranges necessarily a superset of the >> >> individual devices' BARs? >> > >> > Yes. But when you pass in a PCI device to a PV guest you don't >> pass in the >> > bridge. Just the PCI device itself. >> >> Right you are. Which means that basing the whole logic on the >> PCI device BARs is likely wrong anyway, not just because it >> doesn't account for other MMIO ranges. > > Right, but that is OK. When you pass in a PCI device to a PV guest > you > only care about that specific device driver being able to access its > BARs. Maybe I'm reading this wrong, but my understanding is that you cannot pass PCI bridges to domU anyway (in HVM - I tried). Is that not the case? I'm particularly interested in this for two reasons: 1) Some GPUs (Nvidia?) use bus resets to reset the GPU 2) Multi-GPU cards (e.g. GTX690/Grid K2) come with a PCIe bridge of their own. I am successfully passing a modified GTX680 (as either a Grid K2 or Quadro K5000) to a domU, but have completely failed to get a modified GTX690 (Grid K2, exact same GPU as the GTX680) to work with passthru. The only theory I have is that the extra PCIe bridge is the problem (possibly a compound problem that only manigests when there is a PLX (as per GTX690) PCIe bridge behind a NF200 PCIe bridge, behind an Intel PCIe bridge. Gordan -- 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/