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

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 13.04.12 at 14:08, David Vrabel <david.vrabel@xxxxxxxxxx> wrote:
> From: David Vrabel <david.vrabel@xxxxxxxxxx>
> 
> 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.

... and where "direct" access doesn't work either? Are there really
machines where Xen works on but this doesn't work? (Or, in case
this is disabled in your config, is it really useful to have
CONFIG_PCI_DIRECT disabled?)

That's just a comment on the description, the patch itself is fine
nevertheless (but should probably be sent to the x86 and/or PCI
maintainers).

Jan

> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>

Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

> Cc: stable@xxxxxxxxxx 
> ---
>  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
> 
> 
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> http://lists.xen.org/xen-devel 




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