Re: [Xen-devel] [PATCH RFC 1/4] x86/dom0: prevent access to MMCFG areas for PVH Dom0

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Fri, Jun 30, 2017 at 05:27:06AM -0600, Jan Beulich wrote:
> >>> Roger Pau Monne <roger.pau@xxxxxxxxxx> 04/24/17 1:52 PM >>>
> >--- a/xen/arch/x86/dom0_build.c
> >+++ b/xen/arch/x86/dom0_build.c
> >@@ -18,6 +18,8 @@
>  >#include <asm/p2m.h>
>  >#include <asm/setup.h>
>  >
> >+#include "x86_64/mmconfig.h"
> 
> Not just but also because of this I'd prefer if this was taken care of in the
> MMCFG code itself, also covering ranges which are being added post-
> boot. Presumably in/from pci_mmcfg_arch_{en,dis}able().

The problem with this approach is that at the point in the boot where
pci_mmcfg_arch_enable gets called (from acpi_mmcfg_init) the domain
has not yet been created, so it's not possible to call
iomem_deny_access, and in any case the iomem ranges are initialized in
dom0_setup_permissions, so that would get overwritten.

Roger.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel