[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>

diff --git a/drivers/char/agp/agp.h b/drivers/char/agp/agp.h
index ad9c113..c1fe013 100644
--- a/drivers/char/agp/agp.h
+++ b/drivers/char/agp/agp.h
@@ -278,6 +278,8 @@
 #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;
diff --git a/drivers/char/agp/ali-agp.c b/drivers/char/agp/ali-agp.c
index 0212feb..9c9c9c2 100644
--- a/drivers/char/agp/ali-agp.c
+++ b/drivers/char/agp/ali-agp.c
@@ -150,7 +150,7 @@
 	pci_read_config_dword(agp_bridge->dev, ALI_CACHE_FLUSH_CTRL, &temp);
 	pci_write_config_dword(agp_bridge->dev, ALI_CACHE_FLUSH_CTRL,
 			(((temp & ALI_CACHE_FLUSH_ADDR_MASK) |
-			  virt_to_phys(addr)) | ALI_CACHE_FLUSH_EN ));
+			  virt_to_gart(addr)) | ALI_CACHE_FLUSH_EN ));
 	return addr;
 }
 
@@ -174,7 +174,7 @@
 	pci_read_config_dword(agp_bridge->dev, ALI_CACHE_FLUSH_CTRL, &temp);
 	pci_write_config_dword(agp_bridge->dev, ALI_CACHE_FLUSH_CTRL,
 			(((temp & ALI_CACHE_FLUSH_ADDR_MASK) |
-			  virt_to_phys(addr)) | ALI_CACHE_FLUSH_EN));
+			  virt_to_gart(addr)) | ALI_CACHE_FLUSH_EN));
 	agp_generic_destroy_page(addr);
 }
 
diff --git a/drivers/char/agp/amd-k7-agp.c b/drivers/char/agp/amd-k7-agp.c
index e62a3c2..3a41672 100644
--- a/drivers/char/agp/amd-k7-agp.c
+++ b/drivers/char/agp/amd-k7-agp.c
@@ -43,7 +43,7 @@
 
 	SetPageReserved(virt_to_page(page_map->real));
 	global_cache_flush();
-	page_map->remapped = ioremap_nocache(virt_to_phys(page_map->real),
+	page_map->remapped = ioremap_nocache(virt_to_gart(page_map->real),
 					    PAGE_SIZE);
 	if (page_map->remapped == NULL) {
 		ClearPageReserved(virt_to_page(page_map->real));
@@ -154,7 +154,7 @@
 
 	agp_bridge->gatt_table_real = (u32 *)page_dir.real;
 	agp_bridge->gatt_table = (u32 __iomem *)page_dir.remapped;
-	agp_bridge->gatt_bus_addr = virt_to_phys(page_dir.real);
+	agp_bridge->gatt_bus_addr = virt_to_gart(page_dir.real);
 
 	/* Get the address for the gart region.
 	 * This is a bus address even on the alpha, b/c its
@@ -167,7 +167,7 @@
 
 	/* Calculate the agp offset */
 	for (i = 0; i < value->num_entries / 1024; i++, addr += 0x00400000) {
-		writel(virt_to_phys(amd_irongate_private.gatt_pages[i]->real) | 1,
+		writel(virt_to_gart(amd_irongate_private.gatt_pages[i]->real) | 1,
 			page_dir.remapped+GET_PAGE_DIR_OFF(addr));
 		readl(page_dir.remapped+GET_PAGE_DIR_OFF(addr));	/* PCI Posting. */
 	}
diff --git a/drivers/char/agp/amd64-agp.c b/drivers/char/agp/amd64-agp.c
index 399c042..1407945 100644
--- a/drivers/char/agp/amd64-agp.c
+++ b/drivers/char/agp/amd64-agp.c
@@ -219,7 +219,7 @@
 
 static int amd_8151_configure(void)
 {
-	unsigned long gatt_bus = virt_to_phys(agp_bridge->gatt_table_real);
+	unsigned long gatt_bus = virt_to_gart(agp_bridge->gatt_table_real);
 
 	/* Configure AGP regs in each x86-64 host bridge. */
 	for_each_nb() {
@@ -591,7 +591,7 @@
 {
 	struct agp_bridge_data *bridge = pci_get_drvdata(pdev);
 
-	release_mem_region(virt_to_phys(bridge->gatt_table_real),
+	release_mem_region(virt_to_gart(bridge->gatt_table_real),
 			   amd64_aperture_sizes[bridge->aperture_size_idx].size);
 	agp_remove_bridge(bridge);
 	agp_put_bridge(bridge);
diff --git a/drivers/char/agp/ati-agp.c b/drivers/char/agp/ati-agp.c
index a65f882..e572ced 100644
--- a/drivers/char/agp/ati-agp.c
+++ b/drivers/char/agp/ati-agp.c
@@ -61,7 +61,7 @@
 
 	SetPageReserved(virt_to_page(page_map->real));
 	err = map_page_into_agp(virt_to_page(page_map->real));
-	page_map->remapped = ioremap_nocache(virt_to_phys(page_map->real),
+	page_map->remapped = ioremap_nocache(virt_to_gart(page_map->real),
 					    PAGE_SIZE);
 	if (page_map->remapped == NULL || err) {
 		ClearPageReserved(virt_to_page(page_map->real));
@@ -343,7 +343,7 @@
 
 	agp_bridge->gatt_table_real = (u32 *)page_dir.real;
 	agp_bridge->gatt_table = (u32 __iomem *) page_dir.remapped;
-	agp_bridge->gatt_bus_addr = virt_to_bus(page_dir.real);
+	agp_bridge->gatt_bus_addr = virt_to_gart(page_dir.real);
 
 	/* Write out the size register */
 	current_size = A_SIZE_LVL2(agp_bridge->current_size);
@@ -373,7 +373,7 @@
 
 	/* Calculate the agp offset */
 	for(i = 0; i < value->num_entries / 1024; i++, addr += 0x00400000) {
-		writel(virt_to_bus(ati_generic_private.gatt_pages[i]->real) | 1,
+		writel(virt_to_gart(ati_generic_private.gatt_pages[i]->real) | 1,
 			page_dir.remapped+GET_PAGE_DIR_OFF(addr));
 		readl(page_dir.remapped+GET_PAGE_DIR_OFF(addr));	/* PCI Posting. */
 	}
diff --git a/drivers/char/agp/backend.c b/drivers/char/agp/backend.c
index 2f3dfb6..4d4e602 100644
--- a/drivers/char/agp/backend.c
+++ b/drivers/char/agp/backend.c
@@ -148,7 +148,7 @@
 			return -ENOMEM;
 		}
 
-		bridge->scratch_page_real = virt_to_phys(addr);
+		bridge->scratch_page_real = virt_to_gart(addr);
 		bridge->scratch_page =
 		    bridge->driver->mask_memory(bridge, bridge->scratch_page_real, 0);
 	}
@@ -189,7 +189,7 @@
 err_out:
 	if (bridge->driver->needs_scratch_page)
 		bridge->driver->agp_destroy_page(
-				phys_to_virt(bridge->scratch_page_real));
+				gart_to_virt(bridge->scratch_page_real));
 	if (got_gatt)
 		bridge->driver->free_gatt_table(bridge);
 	if (got_keylist) {
@@ -214,7 +214,7 @@
 	if (bridge->driver->agp_destroy_page &&
 	    bridge->driver->needs_scratch_page)
 		bridge->driver->agp_destroy_page(
-				phys_to_virt(bridge->scratch_page_real));
+				gart_to_virt(bridge->scratch_page_real));
 }
 
 /* When we remove the global variable agp_bridge from all drivers
diff --git a/drivers/char/agp/efficeon-agp.c b/drivers/char/agp/efficeon-agp.c
index 1383c31..ac19fdc 100644
--- a/drivers/char/agp/efficeon-agp.c
+++ b/drivers/char/agp/efficeon-agp.c
@@ -219,7 +219,7 @@
 
 		efficeon_private.l1_table[index] = page;
 
-		value = __pa(page) | pati | present | index;
+		value = virt_to_gart(page) | pati | present | index;
 
 		pci_write_config_dword(agp_bridge->dev,
 			EFFICEON_ATTPAGE, value);
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index c321a92..d62505b 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -153,7 +153,7 @@
 	}
 	if (curr->page_count != 0) {
 		for (i = 0; i < curr->page_count; i++) {
-			curr->bridge->driver->agp_destroy_page(phys_to_virt(curr->memory[i]));
+			curr->bridge->driver->agp_destroy_page(gart_to_virt(curr->memory[i]));
 		}
 	}
 	agp_free_key(curr->key);
@@ -209,7 +209,7 @@
 			agp_free_memory(new);
 			return NULL;
 		}
-		new->memory[i] = virt_to_phys(addr);
+		new->memory[i] = virt_to_gart(addr);
 		new->page_count++;
 	}
        new->bridge = bridge;
@@ -806,8 +806,7 @@
 				break;
 			}
 
-			table = (char *) __get_free_pages(GFP_KERNEL,
-							  page_order);
+			table = alloc_gatt_pages(page_order);
 
 			if (table == NULL) {
 				i++;
@@ -838,7 +837,7 @@
 		size = ((struct aper_size_info_fixed *) temp)->size;
 		page_order = ((struct aper_size_info_fixed *) temp)->page_order;
 		num_entries = ((struct aper_size_info_fixed *) temp)->num_entries;
-		table = (char *) __get_free_pages(GFP_KERNEL, page_order);
+		table = alloc_gatt_pages(page_order);
 	}
 
 	if (table == NULL)
@@ -853,7 +852,7 @@
 	agp_gatt_table = (void *)table;
 
 	bridge->driver->cache_flush();
-	bridge->gatt_table = ioremap_nocache(virt_to_phys(table),
+	bridge->gatt_table = ioremap_nocache(virt_to_gart(table),
 					(PAGE_SIZE * (1 << page_order)));
 	bridge->driver->cache_flush();
 
@@ -861,11 +860,11 @@
 		for (page = virt_to_page(table); page <= virt_to_page(table_end); page++)
 			ClearPageReserved(page);
 
-		free_pages((unsigned long) table, page_order);
+		free_gatt_pages(table, page_order);
 
 		return -ENOMEM;
 	}
-	bridge->gatt_bus_addr = virt_to_phys(bridge->gatt_table_real);
+	bridge->gatt_bus_addr = virt_to_gart(bridge->gatt_table_real);
 
 	/* AK: bogus, should encode addresses > 4GB */
 	for (i = 0; i < num_entries; i++) {
@@ -919,7 +918,7 @@
 	for (page = virt_to_page(table); page <= virt_to_page(table_end); page++)
 		ClearPageReserved(page);
 
-	free_pages((unsigned long) bridge->gatt_table_real, page_order);
+	free_gatt_pages(bridge->gatt_table_real, page_order);
 
 	agp_gatt_table = NULL;
 	bridge->gatt_table = NULL;
diff --git a/drivers/char/agp/hp-agp.c b/drivers/char/agp/hp-agp.c
index 6052bfa..99762b6 100644
--- a/drivers/char/agp/hp-agp.c
+++ b/drivers/char/agp/hp-agp.c
@@ -110,7 +110,7 @@
 	hp->gart_size = HP_ZX1_GART_SIZE;
 	hp->gatt_entries = hp->gart_size / hp->io_page_size;
 
-	hp->io_pdir = phys_to_virt(readq(hp->ioc_regs+HP_ZX1_PDIR_BASE));
+	hp->io_pdir = gart_to_virt(readq(hp->ioc_regs+HP_ZX1_PDIR_BASE));
 	hp->gatt = &hp->io_pdir[HP_ZX1_IOVA_TO_PDIR(hp->gart_base)];
 
 	if (hp->gatt[0] != HP_ZX1_SBA_IOMMU_COOKIE) {
@@ -248,7 +248,7 @@
 	agp_bridge->mode = readl(hp->lba_regs+hp->lba_cap_offset+PCI_AGP_STATUS);
 
 	if (hp->io_pdir_owner) {
-		writel(virt_to_phys(hp->io_pdir), hp->ioc_regs+HP_ZX1_PDIR_BASE);
+		writel(virt_to_gart(hp->io_pdir), hp->ioc_regs+HP_ZX1_PDIR_BASE);
 		readl(hp->ioc_regs+HP_ZX1_PDIR_BASE);
 		writel(hp->io_tlb_ps, hp->ioc_regs+HP_ZX1_TCNFG);
 		readl(hp->ioc_regs+HP_ZX1_TCNFG);
diff --git a/drivers/char/agp/i460-agp.c b/drivers/char/agp/i460-agp.c
index adbea89..9494329 100644
--- a/drivers/char/agp/i460-agp.c
+++ b/drivers/char/agp/i460-agp.c
@@ -372,7 +372,7 @@
 	}
 	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 @@
 	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);
 }
 
diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c
index 6a5047e..51266d6 100644
--- a/drivers/char/agp/intel-agp.c
+++ b/drivers/char/agp/intel-agp.c
@@ -286,7 +286,7 @@
 	if (new == NULL)
 		return NULL;
 
-	new->memory[0] = virt_to_phys(addr);
+	new->memory[0] = virt_to_gart(addr);
 	if (pg_count == 4) {
 		/* kludge to get 4 physical pages for ARGB cursor */
 		new->memory[1] = new->memory[0] + PAGE_SIZE;
@@ -329,10 +329,10 @@
 	agp_free_key(curr->key);
 	if(curr->type == AGP_PHYS_MEMORY) {
 		if (curr->page_count == 4)
-			i8xx_destroy_pages(phys_to_virt(curr->memory[0]));
+			i8xx_destroy_pages(gart_to_virt(curr->memory[0]));
 		else
 			agp_bridge->driver->agp_destroy_page(
-				 phys_to_virt(curr->memory[0]));
+				 gart_to_virt(curr->memory[0]));
 		vfree(curr->memory);
 	}
 	kfree(curr);
diff --git a/drivers/char/agp/sworks-agp.c b/drivers/char/agp/sworks-agp.c
index 10c2330..a9fb12c 100644
--- a/drivers/char/agp/sworks-agp.c
+++ b/drivers/char/agp/sworks-agp.c
@@ -51,7 +51,7 @@
 	}
 	SetPageReserved(virt_to_page(page_map->real));
 	global_cache_flush();
-	page_map->remapped = ioremap_nocache(virt_to_phys(page_map->real), 
+	page_map->remapped = ioremap_nocache(virt_to_gart(page_map->real),
 					    PAGE_SIZE);
 	if (page_map->remapped == NULL) {
 		ClearPageReserved(virt_to_page(page_map->real));
@@ -162,7 +162,7 @@
 	/* Create a fake scratch directory */
 	for(i = 0; i < 1024; i++) {
 		writel(agp_bridge->scratch_page, serverworks_private.scratch_dir.remapped+i);
-		writel(virt_to_phys(serverworks_private.scratch_dir.real) | 1, page_dir.remapped+i);
+		writel(virt_to_gart(serverworks_private.scratch_dir.real) | 1, page_dir.remapped+i);
 	}
 
 	retval = serverworks_create_gatt_pages(value->num_entries / 1024);
@@ -174,7 +174,7 @@
 
 	agp_bridge->gatt_table_real = (u32 *)page_dir.real;
 	agp_bridge->gatt_table = (u32 __iomem *)page_dir.remapped;
-	agp_bridge->gatt_bus_addr = virt_to_phys(page_dir.real);
+	agp_bridge->gatt_bus_addr = virt_to_gart(page_dir.real);
 
 	/* Get the address for the gart region.
 	 * This is a bus address even on the alpha, b/c its
@@ -187,7 +187,7 @@
 	/* Calculate the agp offset */	
 
 	for(i = 0; i < value->num_entries / 1024; i++)
-		writel(virt_to_phys(serverworks_private.gatt_pages[i]->real)|1, page_dir.remapped+i);
+		writel(virt_to_gart(serverworks_private.gatt_pages[i]->real)|1, page_dir.remapped+i);
 
 	return 0;
 }
diff --git a/drivers/char/agp/uninorth-agp.c b/drivers/char/agp/uninorth-agp.c
index a673971..c825531 100644
--- a/drivers/char/agp/uninorth-agp.c
+++ b/drivers/char/agp/uninorth-agp.c
@@ -407,7 +407,7 @@
 
 	bridge->gatt_table_real = (u32 *) table;
 	bridge->gatt_table = (u32 *)table;
-	bridge->gatt_bus_addr = virt_to_phys(table);
+	bridge->gatt_bus_addr = virt_to_gart(table);
 
 	for (i = 0; i < num_entries; i++)
 		bridge->gatt_table[i] = 0;
diff --git a/include/asm-alpha/agp.h b/include/asm-alpha/agp.h
index c99dbbb..ef855a3 100644
--- a/include/asm-alpha/agp.h
+++ b/include/asm-alpha/agp.h
@@ -10,4 +10,14 @@
 #define flush_agp_mappings() 
 #define flush_agp_cache() mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-i386/agp.h b/include/asm-i386/agp.h
index a917ff5..b82f5f3 100644
--- a/include/asm-i386/agp.h
+++ b/include/asm-i386/agp.h
@@ -21,4 +21,14 @@
    worth it. Would need a page for it. */
 #define flush_agp_cache() asm volatile("wbinvd":::"memory")
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-ia64/agp.h b/include/asm-ia64/agp.h
index d1316f1..4e517f0 100644
--- a/include/asm-ia64/agp.h
+++ b/include/asm-ia64/agp.h
@@ -18,4 +18,14 @@
 #define flush_agp_mappings()		/* nothing */
 #define flush_agp_cache()		mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif /* _ASM_IA64_AGP_H */
diff --git a/include/asm-ppc/agp.h b/include/asm-ppc/agp.h
index be27cfa..ca9e423 100644
--- a/include/asm-ppc/agp.h
+++ b/include/asm-ppc/agp.h
@@ -10,4 +10,14 @@
 #define flush_agp_mappings()
 #define flush_agp_cache() mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-ppc64/agp.h b/include/asm-ppc64/agp.h
index be27cfa..ca9e423 100644
--- a/include/asm-ppc64/agp.h
+++ b/include/asm-ppc64/agp.h
@@ -10,4 +10,14 @@
 #define flush_agp_mappings()
 #define flush_agp_cache() mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-sparc64/agp.h b/include/asm-sparc64/agp.h
index ba05bdf..58f8cb6 100644
--- a/include/asm-sparc64/agp.h
+++ b/include/asm-sparc64/agp.h
@@ -8,4 +8,14 @@
 #define flush_agp_mappings() 
 #define flush_agp_cache() mb()
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif
diff --git a/include/asm-x86_64/agp.h b/include/asm-x86_64/agp.h
index 0bb9019..06c52ee 100644
--- a/include/asm-x86_64/agp.h
+++ b/include/asm-x86_64/agp.h
@@ -19,4 +19,14 @@
    worth it. Would need a page for it. */
 #define flush_agp_cache() asm volatile("wbinvd":::"memory")
 
+/* Convert a physical address to an address suitable for the GART. */
+#define phys_to_gart(x) (x)
+#define gart_to_phys(x) (x)
+
+/* GATT allocation. Returns/accepts GATT kernel virtual address. */
+#define alloc_gatt_pages(order)		\
+	((char *)__get_free_pages(GFP_KERNEL, (order)))
+#define free_gatt_pages(table, order)	\
+	free_pages((unsigned long)(table), (order))
+
 #endif