x86/numa_emulation: Recalculate numa_nodes_parsed from emulated nodes

When emulating NUMA, the kernel's emulated NUMA configuration may contain
more or less nodes than there are physical nodes.

In numa_emulation(), we recalculate numa_meminfo/numa_distance/__apicid_to_node
according to the number of emulated nodes, except numa_nodes_parsed, which is
arguably an omission.

Recalculate numa_nodes_parsed as well.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: bp@alien8.de
Cc: kirill@shutemov.name
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/20170708013059.29708-4-richard.weiyang@gmail.com
[ Changelog fixes. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/mm/numa_emulation.c

@@ -395,6 +395,13 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
 	/* commit */
 	*numa_meminfo = ei;
 
+	/* Make sure numa_nodes_parsed only contains emulated nodes */
+	nodes_clear(numa_nodes_parsed);
+	for (i = 0; i < ARRAY_SIZE(ei.blk); i++)
+		if (ei.blk[i].start != ei.blk[i].end &&
+		    ei.blk[i].nid != NUMA_NO_NODE)
+			node_set(ei.blk[i].nid, numa_nodes_parsed);
+
 	/*
 	 * Transform __apicid_to_node table to use emulated nids by
 	 * reverse-mapping phys_nid.  The maps should always exist but fall