[PATCH] xen: don't use PCI BIOS service for configuration space accesses

[David Vrabel <david.vrabel@citrix.com>]

From: David Vrabel <david.vrabel@citrix.com>

The accessing PCI configuration space with the PCI BIOS service does
not work in PV guests.

This fixes boot on systems without MMCONFIG or where the BIOS hasn't
marked the MMCONFIG region as reserved in the e820 map.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: stable@kernel.org
---
 arch/x86/xen/enlighten.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index b132ade..dbb5bb7 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -63,6 +63,7 @@
 #include <asm/stackprotector.h>
 #include <asm/hypervisor.h>
 #include <asm/mwait.h>
+#include <asm/pci_x86.h>
 
 #ifdef CONFIG_ACPI
 #include <linux/acpi.h>
@@ -1365,7 +1366,9 @@ asmlinkage void __init xen_start_kernel(void)
 		/* Make sure ACS will be enabled */
 		pci_request_acs();
 	}
-		
+
+	/* PCI BIOS service won't work from a PV guest. */
+	pci_probe &= ~PCI_PROBE_BIOS;
 
 	xen_raw_console_write("about to get started...\n");
 
-- 
1.7.2.5