xen/pci: don't use PCI BIOS service for configuration space accesses

commit 76a8df7b49168509df02461f83fab117a4a86e08 upstream.

The accessing PCI configuration space with the PCI BIOS32 service does
not work in PV guests.

On systems without MMCONFIG or where the BIOS hasn't marked the
MMCONFIG region as reserved in the e820 map, the BIOS service is
probed (even though direct access is preferred) and this hangs.

Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
[v1: Fixed compile error when CONFIG_PCI is not set]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 0fb662abcebc8e36fc46725996d5afebab4eda21..b50c5931f40b3fe2facb2cebb1cbde9029e6b65c 100644 (file)
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -62,6 +62,7 @@
 #include <asm/reboot.h>
 #include <asm/stackprotector.h>
 #include <asm/hypervisor.h>
+#include <asm/pci_x86.h>
 
 #include "xen-ops.h"
 #include "mmu.h"
@@ -1259,8 +1260,10 @@ asmlinkage void __init xen_start_kernel(void)
                /* Make sure ACS will be enabled */
                pci_request_acs();
        }
-               
-
+#ifdef CONFIG_PCI
+       /* PCI BIOS service won't work from a PV guest. */
+       pci_probe &= ~PCI_PROBE_BIOS;
+#endif
        xen_raw_console_write("about to get started...\n");
 
        xen_setup_runstate_info(0);