Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933494AbeAKOVr (ORCPT + 1 other); Thu, 11 Jan 2018 09:21:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:53222 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754252AbeAKOVq (ORCPT ); Thu, 11 Jan 2018 09:21:46 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5D25D21104 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=helgaas@kernel.org Date: Thu, 11 Jan 2018 08:21:41 -0600 From: Bjorn Helgaas To: Christian =?iso-8859-1?Q?K=F6nig?= Cc: bhelgaas@google.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, torvalds@linux-foundation.org, aaro.koskinen@iki.fi, andy.shevchenko@gmail.com, boris.ostrovsky@oracle.com, jgross@suse.com, alexander.deucher@amd.com, airlied@linux.ie Subject: Re: [PATCH 2/2] x86/PCI: limit the size of the 64bit window to 256GB v3 Message-ID: <20180111142141.GA3672@bhelgaas-glaptop.roam.corp.google.com> References: <20180111132330.2682-1-christian.koenig@amd.com> <20180111132330.2682-2-christian.koenig@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180111132330.2682-2-christian.koenig@amd.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Thu, Jan 11, 2018 at 02:23:30PM +0100, Christian K?nig wrote: > Avoid problems with BIOS implementations which don't report all used > resources to the OS by only allocating a 256GB window directly below the > hardware limit. > > For the full hardware documentation see: > https://support.amd.com/TechDocs/49125_15h_Models_30h-3Fh_BKDG.pdf If you can supply a section number, I'll add it here. That spec is 700 pages, so a hint would be useful. > Fixes a silent reboot loop reported by Aaro Koskinen on > an AMD-based MSI MS-7699/760GA-P43(FX) system. > > v2: cleanup code a bit more, update comment and explain the hw limit > v3: improve commit message > > Link: https://lkml.kernel.org/r/20180105220412.fzpwqe4zljdawr36@darkstar.musicnaut.iki.fi > Reported-by: Aaro Koskinen > Signed-off-by: Christian K?nig > --- > arch/x86/pci/fixup.c | 19 +++++++++---------- > 1 file changed, 9 insertions(+), 10 deletions(-) > > diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c > index a91280da2ea1..9c1c98d7e3a7 100644 > --- a/arch/x86/pci/fixup.c > +++ b/arch/x86/pci/fixup.c > @@ -662,10 +662,11 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2033, quirk_no_aersid); > */ > static void pci_amd_enable_64bit_bar(struct pci_dev *dev) > { > - unsigned i; > u32 base, limit, high; > - struct resource *res, *conflict; > struct pci_dev *other; > + struct resource *res; > + unsigned i; > + int r; > > if (!(pci_probe & PCI_BIG_ROOT_WINDOW)) > return; > @@ -702,19 +703,17 @@ static void pci_amd_enable_64bit_bar(struct pci_dev *dev) > if (!res) > return; > > + /* Allocate a 256GB window directly below the 0xfd00000000 hw limit */ > res->name = "PCI Bus 0000:00"; > res->flags = IORESOURCE_PREFETCH | IORESOURCE_MEM | > IORESOURCE_MEM_64 | IORESOURCE_WINDOW; > - res->start = 0x100000000ull; > + res->start = 0xbd00000000ull; > res->end = 0xfd00000000ull - 1; > > - /* Just grab the free area behind system memory for this */ > - while ((conflict = request_resource_conflict(&iomem_resource, res))) { > - if (conflict->end >= res->end) { > - kfree(res); > - return; > - } > - res->start = conflict->end + 1; > + r = request_resource(&iomem_resource, res); > + if (r) { > + kfree(res); > + return; > } > > dev_info(&dev->dev, "adding root bus resource %pR\n", res); > -- > 2.11.0 >