x86-32, memblock: Make add_highpages honor early reserved ranges

Originally the only early reserved range that is overlapped with high
pages is "KVA RAM", but we already do remove that from the active ranges.

However, It turns out Xen could have that kind of overlapping to support memory
ballooning.x

So we need to make add_highpage_with_active_regions() to subtract
memblock reserved just like low ram; this is the proper design anyway.

In this patch, refactering get_freel_all_memory_range() to make it can
be used by add_highpage_with_active_regions().  Also we don't need to
remove "KVA RAM" from active ranges.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4CABB183.1040607@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/mm/memblock.c

@@ -156,7 +156,8 @@ static int __init count_early_node_map(int nodeid)
 	return data.nr;
 }
 
-int __init get_free_all_memory_range(struct range **rangep, int nodeid)
+int __init __get_free_all_memory_range(struct range **rangep, int nodeid,
+			 unsigned long start_pfn, unsigned long end_pfn)
 {
 	int count;
 	struct range *range;
@@ -172,9 +173,9 @@ int __init get_free_all_memory_range(struct range **rangep, int nodeid)
 	 * at first
 	 */
 	nr_range = add_from_early_node_map(range, count, nr_range, nodeid);
-#ifdef CONFIG_X86_32
-	subtract_range(range, count, max_low_pfn, -1ULL);
-#endif
+	subtract_range(range, count, 0, start_pfn);
+	subtract_range(range, count, end_pfn, -1ULL);
+
 	memblock_x86_subtract_reserved(range, count);
 	nr_range = clean_sort_range(range, count);
 
@@ -182,6 +183,16 @@ int __init get_free_all_memory_range(struct range **rangep, int nodeid)
 	return nr_range;
 }
 
+int __init get_free_all_memory_range(struct range **rangep, int nodeid)
+{
+	unsigned long end_pfn = -1UL;
+
+#ifdef CONFIG_X86_32
+	end_pfn = max_low_pfn;
+#endif
+	return __get_free_all_memory_range(rangep, nodeid, 0, end_pfn);
+}
+
 static u64 __init __memblock_x86_memory_in_range(u64 addr, u64 limit, bool get_free)
 {
 	int i, count;