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From:   shaoqin.huang@intel.com
To:     rppt@kernel.org
Cc:     Shaoqin Huang <shaoqin.huang@intel.com>,
        Karolina Drobnik <karolinadrobnik@gmail.com>,
        Rebecca Mckeever <remckee0@gmail.com>,
        David Hildenbrand <david@redhat.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] memblock test: Add test to memblock_add() 129th region
Date:   Mon, 22 Aug 2022 10:33:26 +0800
Message-Id: <20220822023332.127633-2-shaoqin.huang@intel.com>
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From: Shaoqin Huang <shaoqin.huang@intel.com>

Add 129th region into the memblock, and this will trigger the
memblock_double_array() function, this needs valid memory regions. So
using dummy_physical_memory_init() to allocate a valid memory region, and
fake the other memory region, so it make sure the memblock_double_array()
will always choose the valid memory region that is allocated by the
dummy_physical_memory_init(). So memblock_double_array() must success.

Another thing should be done is to restore the memory.regions after
memblock_double_array(), due to now the memory.regions is pointing to a
memory region allocated by dummy_physical_memory_init(). And it will
affect the subsequent tests if we don't restore the memory region. So
simply record the origin region, and restore it after the test.

Signed-off-by: Shaoqin Huang <shaoqin.huang@intel.com>
---
 tools/testing/memblock/tests/basic_api.c | 82 ++++++++++++++++++++++++
 tools/testing/memblock/tests/common.c    |  7 +-
 tools/testing/memblock/tests/common.h    |  3 +
 3 files changed, 90 insertions(+), 2 deletions(-)

diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
index 66f46f261e66..c8e201156cdc 100644
--- a/tools/testing/memblock/tests/basic_api.c
+++ b/tools/testing/memblock/tests/basic_api.c
@@ -326,6 +326,87 @@ static int memblock_add_twice_check(void)
 	return 0;
 }
 
+/*
+ * A test that tries to add the 129th memory block.
+ * Expect to trigger memblock_double_array() to double the
+ * memblock.memory.max, find a new valid memory as
+ * memory.regions.
+ */
+static int memblock_add_many_check(void)
+{
+	int i;
+	void *orig_region;
+	struct region r = {
+		.base = SZ_16K,
+		.size = MEM_SIZE,
+	};
+	phys_addr_t memory_base = SZ_128K;
+
+	PREFIX_PUSH();
+
+	reset_memblock_regions();
+	memblock_allow_resize();
+
+	/*
+	 * Add one valid memory region, this will be choosed to be the memory
+	 * that new memory.regions occupied.
+	 */
+	dummy_physical_memory_init();
+	memblock_add((phys_addr_t)get_memory_block_base(), MEM_SIZE);
+
+	ASSERT_EQ(memblock.memory.cnt, 1);
+	ASSERT_EQ(memblock.memory.total_size, MEM_SIZE);
+
+	for (i = 1; i < INIT_MEMBLOCK_REGIONS; i++) {
+		/* Add some fakes memory region to fulfill the memblock. */
+		memblock_add(memory_base, MEM_SIZE);
+
+		ASSERT_EQ(memblock.memory.cnt, i + 1);
+		ASSERT_EQ(memblock.memory.total_size, (i + 1) * MEM_SIZE);
+
+		/* Keep the gap so these memory region will not be merged. */
+		memory_base += MEM_SIZE * 2;
+	}
+
+	orig_region = memblock.memory.regions;
+
+	/* This adds the 129 memory_region, and makes it double array. */
+	memblock_add((phys_addr_t)memory_base, MEM_SIZE);
+
+	ASSERT_EQ(memblock.memory.cnt, INIT_MEMBLOCK_REGIONS + 1);
+	ASSERT_EQ(memblock.memory.total_size, (INIT_MEMBLOCK_REGIONS + 1) * MEM_SIZE);
+	ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
+
+	ASSERT_EQ(memblock.reserved.cnt, 1);
+	/* This is the size used by new memory.regions. Check it. */
+	ASSERT_EQ(memblock.reserved.total_size, PAGE_ALIGN(INIT_MEMBLOCK_REGIONS * 2 *
+						sizeof(struct memblock_region)));
+
+	/* The base is very small, so it should be insert to the first region. */
+	memblock_add(r.base, r.size);
+	ASSERT_EQ(memblock.memory.regions[0].base, r.base);
+	ASSERT_EQ(memblock.memory.regions[0].size, r.size);
+
+	ASSERT_EQ(memblock.memory.cnt, INIT_MEMBLOCK_REGIONS + 2);
+	ASSERT_EQ(memblock.memory.total_size, (INIT_MEMBLOCK_REGIONS + 2) * MEM_SIZE);
+	ASSERT_EQ(memblock.memory.max, INIT_MEMBLOCK_REGIONS * 2);
+
+	dummy_physical_memory_cleanup();
+
+	/*
+	 * The current memory.regions is occupying a range of memory that
+	 * allocated from dummy_physical_memory_init(). After free the memory,
+	 * we must not use it. So restore the origin memory region to make sure
+	 * the tests can run as normal and not affected by the double array.
+	 */
+	memblock.memory.regions = orig_region;
+	memblock.memory.cnt = INIT_MEMBLOCK_REGIONS;
+
+	test_pass_pop();
+
+	return 0;
+}
+
 static int memblock_add_checks(void)
 {
 	prefix_reset();
@@ -339,6 +420,7 @@ static int memblock_add_checks(void)
 	memblock_add_overlap_bottom_check();
 	memblock_add_within_check();
 	memblock_add_twice_check();
+	memblock_add_many_check();
 
 	prefix_pop();
 
diff --git a/tools/testing/memblock/tests/common.c b/tools/testing/memblock/tests/common.c
index e43b2676af81..89684ec00aa2 100644
--- a/tools/testing/memblock/tests/common.c
+++ b/tools/testing/memblock/tests/common.c
@@ -5,8 +5,6 @@
 #include <linux/memory_hotplug.h>
 #include <linux/build_bug.h>
 
-#define INIT_MEMBLOCK_REGIONS			128
-#define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
 #define PREFIXES_MAX				15
 #define DELIM					": "
 
@@ -75,6 +73,11 @@ void dummy_physical_memory_cleanup(void)
 	free(memory_block.base);
 }
 
+void *get_memory_block_base(void)
+{
+	return memory_block.base;
+}
+
 static void usage(const char *prog)
 {
 	BUILD_BUG_ON(ARRAY_SIZE(help_opts) != ARRAY_SIZE(long_opts) - 1);
diff --git a/tools/testing/memblock/tests/common.h b/tools/testing/memblock/tests/common.h
index 3e7f23d341d7..98b0a0ec629d 100644
--- a/tools/testing/memblock/tests/common.h
+++ b/tools/testing/memblock/tests/common.h
@@ -11,6 +11,8 @@
 #include <../selftests/kselftest.h>
 
 #define MEM_SIZE SZ_16K
+#define INIT_MEMBLOCK_REGIONS			128
+#define INIT_MEMBLOCK_RESERVED_REGIONS		INIT_MEMBLOCK_REGIONS
 
 /**
  * ASSERT_EQ():
@@ -70,6 +72,7 @@ void reset_memblock_attributes(void);
 void setup_memblock(void);
 void dummy_physical_memory_init(void);
 void dummy_physical_memory_cleanup(void);
+void *get_memory_block_base(void);
 void parse_args(int argc, char **argv);
 
 void test_fail(void);
-- 
2.34.1