x86_64: fake apicid_to_node mapping for fake numa

When we are in the emulated NUMA case, we need to make sure that all existing
apicid_to_node mappings that point to real node ID's now point to the
equivalent fake node ID's.

If we simply iterate over all apicid_to_node[] members for each node, we risk
remapping an entry if it shares a node ID with a real node.  Since apicid's
may not be consecutive, we're forced to create an automatic array of
apicid_to_node mappings and then copy it over once we have finished remapping
fake to real nodes.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 1 deletions

diff --git a/arch/x86_64/mm/srat.c b/arch/x86_64/mm/srat.c
index 7ac8ff333e8..acdf03e1914 100644
--- a/arch/x86_64/mm/srat.c
+++ b/arch/x86_64/mm/srat.c
@@ -470,10 +470,13 @@ static int __init find_node_by_addr(unsigned long addr)
  */
 void __init acpi_fake_nodes(const struct bootnode *fake_nodes, int num_nodes)
 {
-        int i;
+        int i, j;
         int fake_node_to_pxm_map[MAX_NUMNODES] = {
                 [0 ... MAX_NUMNODES-1] = PXM_INVAL
         };
+        unsigned char fake_apicid_to_node[MAX_LOCAL_APIC] = {
+                [0 ... MAX_LOCAL_APIC-1] = NUMA_NO_NODE
+        };
 
         printk(KERN_INFO "Faking PXM affinity for fake nodes on real "
                          "topology.\n");
@@ -487,9 +490,17 @@ void __init acpi_fake_nodes(const struct bootnode *fake_nodes, int num_nodes)
                 if (pxm == PXM_INVAL)
                         continue;
                 fake_node_to_pxm_map[i] = pxm;
+                /*
+                 * For each apicid_to_node mapping that exists for this real
+                 * node, it must now point to the fake node ID.
+                 */
+                for (j = 0; j < MAX_LOCAL_APIC; j++)
+                        if (apicid_to_node[j] == nid)
+                                fake_apicid_to_node[j] = i;
         }
         for (i = 0; i < num_nodes; i++)
                 __acpi_map_pxm_to_node(fake_node_to_pxm_map[i], i);
+        memcpy(apicid_to_node, fake_apicid_to_node, sizeof(apicid_to_node));
 
         nodes_clear(nodes_parsed);
         for (i = 0; i < num_nodes; i++)