x86: reserve pages when SandyBridge integrated graphics

SNB graphics devices have a bug that prevent them from accessing certain
memory ranges, namely anything below 1M and in the pages listed in the
table.

Xen does not initialize below 1MB to heap, i.e. below 1MB pages don't be
allocated, so it's unnecessary to reserve memory below the 1 MB mark
that has not already been reserved.

So reserve those pages listed in the table at xen boot if set detect a
SNB gfx device on the CPU to avoid GPU hangs.

Signed-off-by: Xudong Hao <xudong.hao@intel.com>
Acked-by: Keir Fraser <keir@xen.org>

xen/arch/x86/mm.c

@@ -121,6 +121,7 @@
 #include <xen/trace.h>
 #include <asm/setup.h>
 #include <asm/fixmap.h>
+#include <asm/pci.h>
 
 /* Mapping of the fixmap space needed early. */
 l1_pgentry_t __attribute__ ((__section__ (".bss.page_aligned")))
@@ -5824,6 +5825,25 @@ void arch_dump_shared_mem_info(void)
             mem_sharing_get_nr_saved_mfns());
 }
 
+const unsigned long *__init get_platform_badpages(unsigned int *array_size)
+{
+    u32 igd_id;
+    static unsigned long __initdata bad_pages[] = {
+        0x20050000,
+        0x20110000,
+        0x20130000,
+        0x20138000,
+        0x40004000,
+    };
+
+    *array_size = ARRAY_SIZE(bad_pages);
+    igd_id = pci_conf_read32(0, 0, 2, 0, 0);
+    if ( !IS_SNB_GFX(igd_id) )
+        return NULL;
+
+    return bad_pages;
+}
+
 /*
  * Local variables:
  * mode: C

xen/common/page_alloc.c

@@ -152,6 +152,10 @@ void __init init_boot_pages(paddr_t ps, paddr_t pe)
 {
     unsigned long bad_spfn, bad_epfn;
     const char *p;
+#ifdef CONFIG_X86
+    const unsigned long *badpage = NULL;
+    unsigned int i, array_size;
+#endif
 
     ps = round_pgup(ps);
     pe = round_pgdown(pe);
@@ -162,6 +166,25 @@ void __init init_boot_pages(paddr_t ps, paddr_t pe)
 
     bootmem_region_add(ps >> PAGE_SHIFT, pe >> PAGE_SHIFT);
 
+#ifdef CONFIG_X86
+    /* 
+     * Here we put platform-specific memory range workarounds, i.e.
+     * memory known to be corrupt or otherwise in need to be reserved on
+     * specific platforms.
+     * We get these certain pages and remove them from memory region list.
+     */
+    badpage = get_platform_badpages(&array_size);
+    if ( badpage )
+    {
+        for ( i = 0; i < array_size; i++ )
+        {
+            bootmem_region_zap(*badpage >> PAGE_SHIFT,
+                               (*badpage >> PAGE_SHIFT) + 1);
+            badpage++;
+        }
+    }
+#endif
+
     /* Check new pages against the bad-page list. */
     p = opt_badpage;
     while ( *p != '\0' )

xen/drivers/passthrough/vtd/quirks.c

@@ -31,6 +31,7 @@
 #include <xen/keyhandler.h>
 #include <asm/msi.h>
 #include <asm/irq.h>
+#include <asm/pci.h>
 #include <mach_apic.h>
 #include "iommu.h"
 #include "dmar.h"
@@ -47,7 +48,6 @@
 #define IS_CTG(id)    (id == 0x2a408086)
 #define IS_ILK(id)    (id == 0x00408086 || id == 0x00448086 || id== 0x00628086 || id == 0x006A8086)
 #define IS_CPT(id)    (id == 0x01008086 || id == 0x01048086)
-#define IS_SNB_GFX(id) (id == 0x01068086 || id == 0x01168086 || id == 0x01268086 || id == 0x01028086 || id == 0x01128086 || id == 0x01228086 || id == 0x010A8086)
 
 static u32 __read_mostly ioh_id;
 static u32 __initdata igd_id;

xen/include/asm-x86/mm.h

@@ -322,6 +322,7 @@ int is_iomem_page(unsigned long mfn);
 
 void clear_superpage_mark(struct page_info *page);
 
+const unsigned long *get_platform_badpages(unsigned int *array_size);
 /* Per page locks:
  * page_lock() is used for two purposes: pte serialization, and memory sharing.
  *

xen/include/asm-x86/pci.h

@@ -1,6 +1,11 @@
 #ifndef __X86_PCI_H__
 #define __X86_PCI_H__
 
+#define IS_SNB_GFX(id) (id == 0x01068086 || id == 0x01168086 \
+                        || id == 0x01268086 || id == 0x01028086 \
+                        || id == 0x01128086 || id == 0x01228086 \
+                        || id == 0x010A8086 )
+
 struct arch_pci_dev {
     vmask_t used_vectors;
 };