From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hanjun Guo Subject: Re: [PATCH 10/11] XEN / PCI: Remove the dependence on arch x86 when PCI_MMCONFIG=y Date: Wed, 27 May 2015 11:55:45 +0800 Message-ID: <55654041.2040902@linaro.org> References: <1432644564-24746-1-git-send-email-hanjun.guo@linaro.org> <1432644564-24746-11-git-send-email-hanjun.guo@linaro.org> <55647B22.3010801@oracle.com> <55647C94.9080606@oracle.com> <5564893B.2070102@linaro.org> <556494D9.9090007@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <556494D9.9090007@oracle.com> Sender: linux-pci-owner@vger.kernel.org To: Boris Ostrovsky , Tomasz Nowicki , Bjorn Helgaas , Arnd Bergmann , Catalin Marinas , Will Deacon , "Rafael J. Wysocki" Cc: Jiang Liu , Liviu Dudau , Thomas Gleixner , Yijing Wang , Lorenzo Pieralisi , Suravee Suthikulpanit , Mark Salter , linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, Konrad Rzeszutek Wilk , Stefano Stabellini List-Id: linux-acpi@vger.kernel.org On 2015=E5=B9=B405=E6=9C=8826=E6=97=A5 23:44, Boris Ostrovsky wrote: > On 05/26/2015 10:54 AM, Tomasz Nowicki wrote: >> On 26.05.2015 16:00, Boris Ostrovsky wrote: >>> On 05/26/2015 09:54 AM, Boris Ostrovsky wrote: >>>> On 05/26/2015 08:49 AM, Hanjun Guo wrote: >>>>> In drivers/xen/pci.c, there are arch x86 dependent codes when >>>>> CONFIG_PCI_MMCONFIG is enabled, since CONFIG_PCI_MMCONFIG >>>>> depends on ACPI, so this will prevent XEN PCI running on other >>>>> architectures using ACPI with PCI_MMCONFIG enabled (such as ARM64= ). >>>>> >>>>> Fortunatly, it can be sloved in a simple way. In drivers/xen/pci.= c, >>>>> the only x86 dependent code is if ((pci_probe & PCI_PROBE_MMCONF)= =3D=3D >>>>> 0), >>>>> and it's defined in asm/pci_x86.h, the code means that >>>>> if the PCI resource is not probed in PCI_PROBE_MMCONF way, just >>>>> ingnore the xen mcfg init. Actually this is duplicate, because >>>>> if PCI resource is not probed in PCI_PROBE_MMCONF way, the >>>>> pci_mmconfig_list will be empty, and the if (list_empty()) >>>>> after it will do the same job. >>>>> >>>>> So just remove the arch related code and the head file, this >>>>> will be no functional change for x86, and also makes xen/pci.c >>>>> usable for other architectures. >>>>> >>>>> Signed-off-by: Hanjun Guo >>>>> CC: Konrad Rzeszutek Wilk >>>>> CC: Boris Ostrovsky >>>>> --- >>>>> drivers/xen/pci.c | 6 ------ >>>>> 1 file changed, 6 deletions(-) >>>>> >>>>> diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c >>>>> index 6785ebb..9a8dbe3 100644 >>>>> --- a/drivers/xen/pci.c >>>>> +++ b/drivers/xen/pci.c >>>>> @@ -28,9 +28,6 @@ >>>>> #include >>>>> #include >>>>> #include "../pci/pci.h" >>>>> -#ifdef CONFIG_PCI_MMCONFIG >>>>> -#include >>>>> -#endif >>>>> >>>>> static bool __read_mostly pci_seg_supported =3D true; >>>>> >>>>> @@ -222,9 +219,6 @@ static int __init xen_mcfg_late(void) >>>>> if (!xen_initial_domain()) >>>>> return 0; >>>>> >>>>> - if ((pci_probe & PCI_PROBE_MMCONF) =3D=3D 0) >>>>> - return 0; >>>>> - >>>>> if (list_empty(&pci_mmcfg_list)) >>>>> return 0; >>>>> >>>> >>>> (+Stefano who is Xen ARM maintainer) >>>> >>>> This will not build on x86 since pci_mmcfg_list since, for example= , >>>> pci_mmcfg_list is declared in pci_x86.h. >>> >>> >>> And now really with Stefano and with parsable first sentence, sorry= : >>> >>> >>> This will not build on x86 since pci_mmcfg_list, for example, is >>> declared in pci_x86.h. >> >> With this patch set, not any more. Please see preceding patches. > > > OK, I didn't notice this was part of a series. Sorry, I didn't cc you all of those patches. > > Then if not having PCI_PROBE_MMCONF bit set is indeed equivalent to > list_empty(&pci_mmcfg_list), is there any reason for this flag to > (continue to) exist? (and also for pci_mmcfg_arch_init_failed.) I think PCI_PROBE_MMCONF bit is needed for early init of pci mmconfig i= n the x86 arch related code, but for xen_mcfg_late(), it's called after acpi_init() which the mmconfig is ready for use if it's available (the pci_mmcfg_list is empty or not), so not having PCI_PROBE_MMCONF bit set is equivalent list_empty(&pci_mmcfg_list) is not suitable for all cases= , but I think it will be ok after mmconfig is initialized. I think my change log is misleading and needs updating :) Thanks Hanjun