[Xen-devel] [PATCH] linux: fix agp address handling, namely intel-agp

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

Make sure machine addresses are in fact constrained to 32 bits, and assumptions
about multi-page extents being contiguous are being met.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

Index: sle10sp1-2007-03-28/arch/i386/mm/hypervisor.c
===================================================================
--- sle10sp1-2007-03-28.orig/arch/i386/mm/hypervisor.c  2007-03-28 
09:26:03.000000000 +0200
+++ sle10sp1-2007-03-28/arch/i386/mm/hypervisor.c       2007-04-04 
16:49:20.000000000 +0200
@@ -353,6 +353,7 @@ int xen_create_contiguous_region(
 
        return success ? 0 : -ENOMEM;
 }
+EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
 
 void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order)
 {
@@ -437,6 +438,7 @@ void xen_destroy_contiguous_region(unsig
 
        balloon_unlock(flags);
 }
+EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
 
 #ifdef __i386__
 int write_ldt_entry(void *ldt, int entry, __u32 entry_a, __u32 entry_b)
Index: sle10sp1-2007-03-28/drivers/char/agp/generic.c
===================================================================
--- sle10sp1-2007-03-28.orig/drivers/char/agp/generic.c 2007-03-28 
08:47:04.000000000 +0200
+++ sle10sp1-2007-03-28/drivers/char/agp/generic.c      2007-04-04 
16:49:20.000000000 +0200
@@ -51,7 +51,7 @@ int agp_memory_reserved;
  */
 EXPORT_SYMBOL_GPL(agp_memory_reserved);
 
-#if defined(CONFIG_X86)
+#if defined(CONFIG_X86) && !defined(CONFIG_XEN)
 int map_page_into_agp(struct page *page)
 {
        int i;
Index: sle10sp1-2007-03-28/drivers/char/agp/intel-agp.c
===================================================================
--- sle10sp1-2007-03-28.orig/drivers/char/agp/intel-agp.c       2007-03-28 
08:47:04.000000000 +0200
+++ sle10sp1-2007-03-28/drivers/char/agp/intel-agp.c    2007-04-04 
16:49:20.000000000 +0200
@@ -164,6 +164,13 @@ static void *i8xx_alloc_pages(void)
        if (page == NULL)
                return NULL;
 
+#ifdef CONFIG_XEN
+       if (xen_create_contiguous_region((unsigned long)page_address(page), 2, 
32)) {
+               __free_pages(page, 2);
+               return NULL;
+       }
+#endif
+
        if (change_page_attr(page, 4, PAGE_KERNEL_NOCACHE) < 0) {
                global_flush_tlb();
                __free_page(page);
@@ -186,6 +193,9 @@ static void i8xx_destroy_pages(void *add
        page = virt_to_page(addr);
        change_page_attr(page, 4, PAGE_KERNEL);
        global_flush_tlb();
+#ifdef CONFIG_XEN
+       xen_destroy_contiguous_region((unsigned long)page_address(page), 2);
+#endif
        put_page(page);
        unlock_page(page);
        free_pages((unsigned long)addr, 2);
Index: sle10sp1-2007-03-28/include/asm-i386/mach-xen/asm/agp.h
===================================================================
--- sle10sp1-2007-03-28.orig/include/asm-i386/mach-xen/asm/agp.h        
2007-03-28 08:48:23.000000000 +0200
+++ sle10sp1-2007-03-28/include/asm-i386/mach-xen/asm/agp.h     2007-04-04 
16:49:20.000000000 +0200
@@ -13,8 +13,15 @@
  * data corruption on some CPUs.
  */
 
-int map_page_into_agp(struct page *page);
-int unmap_page_from_agp(struct page *page);
+/* Caller's responsibility to call global_flush_tlb() for
+ * performance reasons */
+#define map_page_into_agp(page) ( \
+       xen_create_contiguous_region((unsigned long)page_address(page), 0, 32) \
+       ?: change_page_attr(page, 1, PAGE_KERNEL_NOCACHE))
+#define unmap_page_from_agp(page) ( \
+       xen_destroy_contiguous_region((unsigned long)page_address(page), 0), \
+       /* only a fallback: xen_destroy_contiguous_region uses PAGE_KERNEL */ \
+       change_page_attr(page, 1, PAGE_KERNEL))
 #define flush_agp_mappings() global_flush_tlb()
 
 /* Could use CLFLUSH here if the cpu supports it. But then it would
Index: sle10sp1-2007-03-28/include/asm-x86_64/mach-xen/asm/agp.h
===================================================================
--- sle10sp1-2007-03-28.orig/include/asm-x86_64/mach-xen/asm/agp.h      
2007-03-28 08:48:23.000000000 +0200
+++ sle10sp1-2007-03-28/include/asm-x86_64/mach-xen/asm/agp.h   2007-04-04 
16:49:20.000000000 +0200
@@ -11,8 +11,13 @@
  * with different cachability attributes for the same page.
  */
 
-int map_page_into_agp(struct page *page);
-int unmap_page_from_agp(struct page *page);
+#define map_page_into_agp(page) ( \
+       xen_create_contiguous_region((unsigned long)page_address(page), 0, 32) \
+       ?: change_page_attr(page, 1, PAGE_KERNEL_NOCACHE))
+#define unmap_page_from_agp(page) ( \
+       xen_destroy_contiguous_region((unsigned long)page_address(page), 0), \
+       /* only a fallback: xen_destroy_contiguous_region uses PAGE_KERNEL */ \
+       change_page_attr(page, 1, PAGE_KERNEL))
 #define flush_agp_mappings() global_flush_tlb()
 
 /* Could use CLFLUSH here if the cpu supports it. But then it would



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