[PATCH v4 4/4] nitro_enclaves: Add KUnit tests for contiguous physical memory regions merging

["Longpeng(Mike)" <longpeng2@huawei.com>]

From: Longpeng <longpeng2@huawei.com>

Add KUnit tests for the contiguous physical memory regions merging
functionality from the Nitro Enclaves misc device logic.

We can build the test binary with the following configuration:
  CONFIG_KUNIT=y
  CONFIG_NITRO_ENCLAVES=m
  CONFIG_NITRO_ENCLAVES_MISC_DEV_TEST=y
and install the nitro_enclaves module to run the testcases.

We'll see the following message using dmesg if everything goes well:

[...]     # Subtest: ne_misc_dev_test
[...]     1..1
[...] (NULL device *): Physical mem region address is not 2 MiB aligned
[...] (NULL device *): Physical mem region size is not multiple of 2 MiB
[...] (NULL device *): Physical mem region address is not 2 MiB aligned
[...]     ok 1 - ne_misc_dev_test_merge_phys_contig_memory_regions
[...] ok 1 - ne_misc_dev_test

Signed-off-by: Longpeng <longpeng2@huawei.com>
---
Changes v3 -> v4:
  - "int expect_num" -> "unsigned long  expect_num"  [Andra]
  - rename several variables and structures  [Andra]
  - invoke "kunit_kfree" to free the "regions"  [Andra]

Changes v2 -> v3:
  - update the commit title and commit message.  [Andra]
  - align the fileds in 'struct phys_regions_test'.  [Andra]
  - rename 'phys_regions_testcases' to 'phys_regions_test_cases'.  [Andra]
  - add comments before each test cases.  [Andra]
  - initialize the variables in ne_misc_dev_test_merge_phys_contig_memory_regions.  [Andra]
---
 drivers/virt/nitro_enclaves/ne_misc_dev_test.c | 139 +++++++++++++++++++++++++
 1 file changed, 139 insertions(+)

diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev_test.c b/drivers/virt/nitro_enclaves/ne_misc_dev_test.c
index 6862e99..4648ec02 100644
--- a/drivers/virt/nitro_enclaves/ne_misc_dev_test.c
+++ b/drivers/virt/nitro_enclaves/ne_misc_dev_test.c
@@ -2,7 +2,146 @@
 
 #include <kunit/test.h>
 
+#define MAX_PHYS_REGIONS	16
+#define INVALID_VALUE		(~0ull)
+
+struct ne_phys_regions_test {
+	u64           paddr;
+	u64           size;
+	int           expect_rc;
+	unsigned long expect_num;
+	u64           expect_last_paddr;
+	u64           expect_last_size;
+} phys_regions_test_cases[] = {
+	/*
+	 * Add the region from 0x1000 to (0x1000 + 0x200000 - 1):
+	 *   Expected result:
+	 *       Failed, start address is not 2M-aligned
+	 *
+	 * Now the instance of struct ne_phys_contig_mem_regions is:
+	 *   num = 0
+	 *   regions = {}
+	 */
+	{0x1000, 0x200000, -EINVAL, 0, INVALID_VALUE, INVALID_VALUE},
+
+	/*
+	 * Add the region from 0x200000 to (0x200000 + 0x1000 - 1):
+	 *   Expected result:
+	 *       Failed, size is not 2M-aligned
+	 *
+	 * Now the instance of struct ne_phys_contig_mem_regions is:
+	 *   num = 0
+	 *   regions = {}
+	 */
+	{0x200000, 0x1000, -EINVAL, 0, INVALID_VALUE, INVALID_VALUE},
+
+	/*
+	 * Add the region from 0x200000 to (0x200000 + 0x200000 - 1):
+	 *   Expected result:
+	 *       Successful
+	 *
+	 * Now the instance of struct ne_phys_contig_mem_regions is:
+	 *   num = 1
+	 *   regions = {
+	 *       {start=0x200000, end=0x3fffff}, // len=0x200000
+	 *   }
+	 */
+	{0x200000, 0x200000, 0, 1, 0x200000, 0x200000},
+
+	/*
+	 * Add the region from 0x0 to (0x0 + 0x200000 - 1):
+	 *   Expected result:
+	 *       Successful
+	 *
+	 * Now the instance of struct ne_phys_contig_mem_regions is:
+	 *   num = 2
+	 *   regions = {
+	 *       {start=0x200000, end=0x3fffff}, // len=0x200000
+	 *       {start=0x0,      end=0x1fffff}, // len=0x200000
+	 *   }
+	 */
+	{0x0, 0x200000, 0, 2, 0x0, 0x200000},
+
+	/*
+	 * Add the region from 0x600000 to (0x600000 + 0x400000 - 1):
+	 *   Expected result:
+	 *       Successful
+	 *
+	 * Now the instance of struct ne_phys_contig_mem_regions is:
+	 *   num = 3
+	 *   regions = {
+	 *       {start=0x200000, end=0x3fffff}, // len=0x200000
+	 *       {start=0x0,      end=0x1fffff}, // len=0x200000
+	 *       {start=0x600000, end=0x9fffff}, // len=0x400000
+	 *   }
+	 */
+	{0x600000, 0x400000, 0, 3, 0x600000, 0x400000},
+
+	/*
+	 * Add the region from 0xa00000 to (0xa00000 + 0x400000 - 1):
+	 *   Expected result:
+	 *       Successful, merging case!
+	 *
+	 * Now the instance of struct ne_phys_contig_mem_regions is:
+	 *   num = 3
+	 *   regions = {
+	 *       {start=0x200000, end=0x3fffff}, // len=0x200000
+	 *       {start=0x0,      end=0x1fffff}, // len=0x200000
+	 *       {start=0x600000, end=0xdfffff}, // len=0x800000
+	 *   }
+	 */
+	{0xa00000, 0x400000, 0, 3, 0x600000, 0x800000},
+
+	/*
+	 * Add the region from 0x1000 to (0x1000 + 0x200000 - 1):
+	 *   Expected result:
+	 *       Failed, start address is not 2M-aligned
+	 *
+	 * Now the instance of struct ne_phys_contig_mem_regions is:
+	 *   num = 3
+	 *   regions = {
+	 *       {start=0x200000, end=0x3fffff}, // len=0x200000
+	 *       {start=0x0,      end=0x1fffff}, // len=0x200000
+	 *       {start=0x600000, end=0xdfffff}, // len=0x800000
+	 *   }
+	 */
+	{0x1000, 0x200000, -EINVAL, 3, 0x600000, 0x800000},
+};
+
+static void ne_misc_dev_test_merge_phys_contig_memory_regions(struct kunit *test)
+{
+	struct ne_phys_contig_mem_regions phys_contig_mem_regions = {};
+	int rc = 0;
+	int i = 0;
+
+	phys_contig_mem_regions.regions = kunit_kcalloc(test, MAX_PHYS_REGIONS,
+					sizeof(*phys_contig_mem_regions.regions), GFP_KERNEL);
+	KUNIT_ASSERT_TRUE(test, phys_contig_mem_regions.regions != NULL);
+
+	for (i = 0; i < ARRAY_SIZE(phys_regions_test_cases); i++) {
+		struct ne_phys_regions_test *test_case = &phys_regions_test_cases[i];
+		unsigned long num = 0;
+
+		rc = ne_merge_phys_contig_memory_regions(&phys_contig_mem_regions,
+							 test_case->paddr, test_case->size);
+		KUNIT_EXPECT_EQ(test, rc, test_case->expect_rc);
+		KUNIT_EXPECT_EQ(test, phys_contig_mem_regions.num, test_case->expect_num);
+
+		if (test_case->expect_last_paddr == INVALID_VALUE)
+			continue;
+
+		num = phys_contig_mem_regions.num;
+		KUNIT_EXPECT_EQ(test, phys_contig_mem_regions.regions[num - 1].start,
+				test_case->expect_last_paddr);
+		KUNIT_EXPECT_EQ(test, range_len(&phys_contig_mem_regions.regions[num - 1]),
+				test_case->expect_last_size);
+	}
+
+	kunit_kfree(test, phys_contig_mem_regions.regions);
+}
+
 static struct kunit_case ne_misc_dev_test_cases[] = {
+	KUNIT_CASE(ne_misc_dev_test_merge_phys_contig_memory_regions),
 	{}
 };
 
-- 
1.8.3.1