x86-64, NUMA: Unify emulated apicid -> node mapping transformation

NUMA emulation changes node mappings and thus apicid -> node mapping
needs to be updated accordingly.  srat_64 and amdtopology_64 did this
separately; however, all the necessary information is the mapping from
emulated nodes to physical nodes which is available in
emu_nid_to_phys[].

Implement common __apicid_to_node[] transformation in numa_emulation()
and drop duplicate implementations.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/mm/numa_64.c b/arch/x86/mm/numa_64.c
index bd086eb..722039e 100644
--- a/arch/x86/mm/numa_64.c
+++ b/arch/x86/mm/numa_64.c
@@ -858,7 +858,7 @@
 	static struct numa_meminfo ei __initdata;
 	static struct numa_meminfo pi __initdata;
 	const u64 max_addr = max_pfn << PAGE_SHIFT;
-	int i, ret;
+	int i, j, ret;
 
 	memset(&ei, 0, sizeof(ei));
 	pi = numa_meminfo;
@@ -894,6 +894,20 @@
 	/* commit */
 	numa_meminfo = ei;
 
+	/*
+	 * Transform __apicid_to_node table to use emulated nids by
+	 * reverse-mapping phys_nid.  The maps should always exist but fall
+	 * back to zero just in case.
+	 */
+	for (i = 0; i < ARRAY_SIZE(__apicid_to_node); i++) {
+		if (__apicid_to_node[i] == NUMA_NO_NODE)
+			continue;
+		for (j = 0; j < ARRAY_SIZE(emu_nid_to_phys); j++)
+			if (__apicid_to_node[i] == emu_nid_to_phys[j])
+				break;
+		__apicid_to_node[i] = j < ARRAY_SIZE(emu_nid_to_phys) ? j : 0;
+	}
+
 	/* make sure all emulated nodes are mapped to a physical node */
 	for (i = 0; i < ARRAY_SIZE(emu_nid_to_phys); i++)
 		if (emu_nid_to_phys[i] == NUMA_NO_NODE)