Re: [PATCH 10/11] XEN / PCI: Remove the dependence on arch x86 when PCI_MMCONFIG=y

From: Boris Ostrovsky
Date: Tue May 26 2015 - 09:56:33 EST


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) == 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 <hanjun.guo@xxxxxxxxxx>
CC: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
CC: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
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 <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include "../pci/pci.h"
-#ifdef CONFIG_PCI_MMCONFIG
-#include <asm/pci_x86.h>
-#endif

static bool __read_mostly pci_seg_supported = true;

@@ -222,9 +219,6 @@ static int __init xen_mcfg_late(void)
if (!xen_initial_domain())
return 0;

- if ((pci_probe & PCI_PROBE_MMCONF) == 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 I am not sure I understand why you are trying to do this since AFAIK CONFIG_PCI_MMCONFIG is only defined on x86 so neither pci_x86.h will be included nor xen_mcfg_late() will be defined on ARM.


-boris



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