1 files changed, 33 insertions, 0 deletions

diff --git a/arch/x86_64/mm/srat.c b/arch/x86_64/mm/srat.c
index d96c701dbed6..8b7f85608fa8 100644
--- a/arch/x86_64/mm/srat.c
+++ b/arch/x86_64/mm/srat.c
@@ -17,6 +17,7 @@
 #include <linux/topology.h>
 #include <asm/proto.h>
 #include <asm/numa.h>
+#include <asm/e820.h>
 
 static struct acpi_table_slit *acpi_slit;
 
@@ -196,12 +197,39 @@ acpi_numa_memory_affinity_init(struct acpi_table_memory_affinity *ma)
                nd->start, nd->end);
 }
 
+/* Sanity check to catch more bad SRATs (they are amazingly common).
+   Make sure the PXMs cover all memory. */
+static int nodes_cover_memory(void)
+{
+        int i;
+        unsigned long pxmram, e820ram;
+
+        pxmram = 0;
+        for_each_node_mask(i, nodes_parsed) {
+                unsigned long s = nodes[i].start >> PAGE_SHIFT;
+                unsigned long e = nodes[i].end >> PAGE_SHIFT;
+                pxmram += e - s;
+                pxmram -= e820_hole_size(s, e);
+        }
+
+        e820ram = end_pfn - e820_hole_size(0, end_pfn);
+        if (pxmram < e820ram) {
+                printk(KERN_ERR
+        "SRAT: PXMs only cover %luMB of your %luMB e820 RAM. Not used.\n",
+                        (pxmram << PAGE_SHIFT) >> 20,
+                        (e820ram << PAGE_SHIFT) >> 20);
+                return 0;
+        }
+        return 1;
+}
+
 void __init acpi_numa_arch_fixup(void) {}
 
 /* Use the information discovered above to actually set up the nodes. */
 int __init acpi_scan_nodes(unsigned long start, unsigned long end)
 {
         int i;
+
         if (acpi_numa <= 0)
                 return -1;
 
@@ -212,6 +240,11 @@ int __init acpi_scan_nodes(unsigned long start, unsigned long end)
                         node_clear(i, nodes_parsed);
         }
 
+        if (!nodes_cover_memory()) {
+                bad_srat();
+                return -1;
+        }
+
         memnode_shift = compute_hash_shift(nodes, nodes_weight(nodes_parsed));
         if (memnode_shift < 0) {
                 printk(KERN_ERR