From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752954Ab2A2NL4 (ORCPT ); Sun, 29 Jan 2012 08:11:56 -0500 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:51340 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752134Ab2A2NLy (ORCPT ); Sun, 29 Jan 2012 08:11:54 -0500 Date: Sun, 29 Jan 2012 18:41:39 +0530 From: Vaidyanathan Srinivasan To: Yinghai Lu Cc: Ram Pai , Jesse Barnes , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [BUGFIX][PATCH] pci: check for 4k resource_size alignment in sriov_init Message-ID: <20120129131139.GA19049@dirshya.in.ibm.com> Reply-To: svaidy@linux.vnet.ibm.com References: <20120127191032.GA22999@dirshya.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) x-cbid: 12012913-5564-0000-0000-00000125CBCD Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Yinghai Lu [2012-01-27 13:05:41]: > On Fri, Jan 27, 2012 at 11:10 AM, Vaidyanathan Srinivasan > wrote: > > Hi Ram and Jesse, > > > > I found a trivial issue with page size alignment check on IBM POWER > > box with 64k base page size.  In sriov_init(), changing the check from > > PAGE_SIZE (arch and config dependent) to HW_PAGE_SIZE (always 4k) was > > required to use one of the sriov adapter as PF since the > > resource_size() comes up as 0x8000 and PAGE_SIZE would be 0x10000 for > > pseries boxes. > > > > I think resource_size() could be less than SystemPageSize, but I would > > like your comments/ack/nack on any consequences of checking for only > > 4k alignment here in a system with larger base page size. > > > > Thanks, > > Vaidy > > > > --- > > > >    pci: check for 4k resource_size alignment in sriov_init > > > >    pci sriov_init should check for 4k page size alignment of resource_size > >    even if base page size is larger -- like 64k in powerpc. > > > >    Signed-off-by: Vaidyanathan Srinivasan > > > > diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c > > index 0321fa3..5816fa0 100644 > > --- a/drivers/pci/iov.c > > +++ b/drivers/pci/iov.c > > @@ -474,7 +474,7 @@ found: > >                                     pos + PCI_SRIOV_BAR + i * 4); > >                if (!res->flags) > >                        continue; > > -               if (resource_size(res) & (PAGE_SIZE - 1)) { > > +               if (resource_size(res) & (HW_PAGE_SIZE - 1)) { > >                        rc = -EIO; > >                        goto failed; > >                } > > > > but HW_PAGE_SIZE is only defined for powerpc. My bad, I picked the #define used in other powerpc code. > also there is PAGE_SHIFT around in that function. This gets defined correctly if CONFIG_PPC_64K_PAGES=y. But the actual problem is the need for a generic 4K #define for x86 and other archs. > maybe you can just define another MARCO according to IOV spec? This is a good idea. I could not find an IOV specific requirement. The resource size has to be a multiple of 4K so that the overall resource-size() * PCI_SRIOV_TOTAL_VF will be a multiple of 4K or more. Let me share a patch that has a simple #define in drivers/pci/pci.h, which is needed to get SRIOV cards started on powerpc box. --Vaidy --- pci: check for 4k resource_size alignment in sriov_init pci sriov_init should check for 4k page size alignment of resource_size even if base page size is larger like 64k in powerpc. Signed-off-by: Vaidyanathan Srinivasan diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index 0321fa3..10adede 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -474,7 +474,7 @@ found: pos + PCI_SRIOV_BAR + i * 4); if (!res->flags) continue; - if (resource_size(res) & (PAGE_SIZE - 1)) { + if (resource_size(res) & (HW_PAGE_SIZE_4K - 1)) { rc = -EIO; goto failed; } diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 1009a5e..68703ab 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -6,6 +6,9 @@ #define PCI_CFG_SPACE_SIZE 256 #define PCI_CFG_SPACE_EXP_SIZE 4096 +/* Constants used in the PCI core code */ +#define HW_PAGE_SIZE_4K 0x1000 + /* Functions internal to the PCI core code */ extern int pci_uevent(struct device *dev, struct kobj_uevent_env *env);