[PATCH] AGP fix for Xen VMM

When Linux is running on the Xen virtual machine monitor, physical
addresses are virtualised and cannot be directly referenced by the AGP
GART.  This patch fixes the GART driver for Xen by adding a layer of
abstraction between physical addresses and 'GART addresses'.

Architecture-specific functions are also defined for allocating and freeing
the GATT.  Xen requires this to ensure that table really is contiguous from
the point of view of the GART.

These extra interface functions are defined as 'no-ops' for all existing
architectures that use the GART driver.

Signed-off-by: Keir Fraser <keir@xensource.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dave Jones <davej@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/char/agp/agp.h b/drivers/char/agp/agp.h
index ad9c11391d81..c1fe013c64f3 100644
--- a/drivers/char/agp/agp.h
+++ b/drivers/char/agp/agp.h
@@ -278,6 +278,8 @@ void agp3_generic_cleanup(void);
 #define AGP_GENERIC_SIZES_ENTRIES 11
 extern struct aper_size_info_16 agp3_generic_sizes[];
 
+#define virt_to_gart(x) (phys_to_gart(virt_to_phys(x)))
+#define gart_to_virt(x) (phys_to_virt(gart_to_phys(x)))
 
 extern int agp_off;
 extern int agp_try_unsupported_boot;