Subject: x86: extend get_platform_badpages() interface
From: Jan Beulich <[email-masked]>

Use a structure so along with an address (now frame number) an order can
also be specified.

This is part of XSA-282.

Signed-off-by: Jan Beulich <[email-masked]>
Reviewed-by: Andrew Cooper <[email-masked]>

--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -7111,23 +7111,23 @@ void arch_dump_shared_mem_info(void)
             mem_sharing_get_nr_saved_mfns());
 }
 
-const unsigned long *__init get_platform_badpages(unsigned int *array_size)
+const struct platform_bad_page *__init get_platform_badpages(unsigned int *array_size)
 {
     u32 igd_id;
-    static unsigned long __initdata bad_pages[] = {
-        0x20050000,
-        0x20110000,
-        0x20130000,
-        0x20138000,
-        0x40004000,
+    static const struct platform_bad_page __initconst snb_bad_pages[] = {
+        { .mfn = 0x20050000 >> PAGE_SHIFT },
+        { .mfn = 0x20110000 >> PAGE_SHIFT },
+        { .mfn = 0x20130000 >> PAGE_SHIFT },
+        { .mfn = 0x20138000 >> PAGE_SHIFT },
+        { .mfn = 0x40004000 >> PAGE_SHIFT },
     };
 
-    *array_size = ARRAY_SIZE(bad_pages);
+    *array_size = ARRAY_SIZE(snb_bad_pages);
     igd_id = pci_conf_read32(0, 0, 2, 0, 0);
-    if ( !IS_SNB_GFX(igd_id) )
-        return NULL;
+    if ( IS_SNB_GFX(igd_id) )
+        return snb_bad_pages;
 
-    return bad_pages;
+    return NULL;
 }
 
 void paging_invlpg(struct vcpu *v, unsigned long va)
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -270,7 +270,7 @@ void __init init_boot_pages(paddr_t ps,
     unsigned long bad_spfn, bad_epfn;
     const char *p;
 #ifdef CONFIG_X86
-    const unsigned long *badpage = NULL;
+    const struct platform_bad_page *badpage;
     unsigned int i, array_size;
 #endif
 
@@ -295,8 +295,8 @@ void __init init_boot_pages(paddr_t ps,
     {
         for ( i = 0; i < array_size; i++ )
         {
-            bootmem_region_zap(*badpage >> PAGE_SHIFT,
-                               (*badpage >> PAGE_SHIFT) + 1);
+            bootmem_region_zap(badpage->mfn,
+                               badpage->mfn + (1U << badpage->order));
             badpage++;
         }
     }
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -350,7 +350,13 @@ bool is_iomem_page(mfn_t mfn);
 
 void clear_superpage_mark(struct page_info *page);
 
-const unsigned long *get_platform_badpages(unsigned int *array_size);
+struct platform_bad_page {
+    unsigned long mfn;
+    unsigned int order;
+};
+
+const struct platform_bad_page *get_platform_badpages(unsigned int *array_size);
+
 /* Per page locks:
  * page_lock() is used for two purposes: pte serialization, and memory sharing.
  *