[PATCH i-g-t v3 05/10] tests/intel/xe_svm: add huge page access test for SVM

[Bommu Krishnaiah]

svm-huge-page verifies the Shared Virtual Memory (SVM) functionality
by using huge page access. The test allocates 2MB of aligned memory
to utilize huge pages and verifies GPU access to this memory.

Subtest:
- svm-huge-page: Verifies that the GPU can correctly access memory allocated
  as huge pages (2MB aligned).

Signed-off-by: Bommu Krishnaiah <krishnaiah.bommu at intel.com>
Cc: Oak Zeng <oak.zeng at intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
---
 tests/intel/xe_svm.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/tests/intel/xe_svm.c b/tests/intel/xe_svm.c
index 73a232c47..d9629246c 100644
--- a/tests/intel/xe_svm.c
+++ b/tests/intel/xe_svm.c
@@ -30,6 +30,9 @@
  *
  * SUBTEST: svm-random-access
  * Description: Verifies that the GPU can randomly access and correctly store values in malloc'ed memory.
+ *
+ * SUBTEST: svm-huge-page
+ * Description: verify SVM basic functionality by using huge page access
  */
 
 #include <fcntl.h>
@@ -156,6 +159,49 @@ static void svm_random_access(int fd, uint32_t vm, struct drm_xe_engine_class_in
 	free(dst);
 }
 
+/**
+ * Test the behavior of transparent huge page.
+ * Allocate 2MB of aligned memory so huge page
+ * is used. What happens if driver only migrate
+ * 1 4k page of that buffer to GPU?
+ *
+ * Test result shows that the huge page is splitted
+ * into small pages and only one 4k page is
+ * migrated.
+ */
+static void svm_thp(int fd, uint32_t vm, struct drm_xe_engine_class_instance *eci)
+{
+	uint64_t gpu_va = 0x1a0000;
+	size_t bo_size = xe_bb_size(fd, PAGE_ALIGN_UFENCE);
+	uint32_t size = 1<<21; //2MB
+	uint32_t *dst;
+	int ret;
+
+	struct xe_buffer cmd_buf = {
+		.fd = fd,
+		.gpu_addr = (void *)(uintptr_t)gpu_va,
+		.vm = vm,
+		.size = bo_size,
+		.placement = vram_if_possible(fd, eci->gt_id),
+		.flag = DRM_XE_GEM_CREATE_FLAG_NEEDS_VISIBLE_VRAM,
+	};
+
+	ret = posix_memalign((void **)&dst, size, size);
+	igt_assert_eq(ret, 0);
+	/** TODO huge page advice cause the system hang
+	* when process exit...Very possible a hmm bug
+	**/
+	memset(dst, 0xbe, size);
+
+	xe_create_cmdbuf(&cmd_buf, insert_store, (uint64_t)dst, 0xc0ffee, eci);
+	xe_submit_cmd(&cmd_buf);
+
+	igt_assert_eq(*dst, 0xc0ffee);
+
+	xe_destroy_cmdbuf(&cmd_buf);
+	free(dst);
+}
+
 igt_main
 {
 	int fd;
@@ -184,6 +230,10 @@ igt_main
 		xe_for_each_engine(fd, hwe)
 			svm_random_access(fd, vm, hwe);
 
+	igt_subtest_f("svm-huge-page")
+		xe_for_each_engine(fd, hwe)
+			svm_thp(fd, vm, hwe);
+
 	igt_fixture {
 		xe_vm_destroy(fd, vm);
 		drm_close_driver(fd);
-- 
2.25.1