[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, 2 deletions

diff --git a/drivers/char/agp/i460-agp.c b/drivers/char/agp/i460-agp.c
index adbea896c0d2..94943298c03e 100644
--- a/drivers/char/agp/i460-agp.c
+++ b/drivers/char/agp/i460-agp.c
@@ -372,7 +372,7 @@ static int i460_alloc_large_page (struct lp_desc *lp)
         }
         memset(lp->alloced_map, 0, map_size);
 
-        lp->paddr = virt_to_phys(lpage);
+        lp->paddr = virt_to_gart(lpage);
         lp->refcount = 0;
         atomic_add(I460_KPAGES_PER_IOPAGE, &agp_bridge->current_memory_agp);
         return 0;
@@ -383,7 +383,7 @@ static void i460_free_large_page (struct lp_desc *lp)
         kfree(lp->alloced_map);
         lp->alloced_map = NULL;
 
-        free_pages((unsigned long) phys_to_virt(lp->paddr), I460_IO_PAGE_SHIFT - PAGE_SHIFT);
+        free_pages((unsigned long) gart_to_virt(lp->paddr), I460_IO_PAGE_SHIFT - PAGE_SHIFT);
         atomic_sub(I460_KPAGES_PER_IOPAGE, &agp_bridge->current_memory_agp);
 }