[igt-dev] [PATCH i-g-t] i915/gem_mmap_gtt: Test mmap_gtt extension validity

[Abdiel Janulgue]

If we accidentally modify the mmap_gtt ioctl struct sizes in our headers,
we might end up feeding garbage into the ioctl and start validating
that as our flags for the upcoming mmap_offset ioctl. This ensures header
changes don't mess up with our existing mmap_gtt ioctl.

Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
---
 tests/i915/gem_mmap_gtt.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/tests/i915/gem_mmap_gtt.c b/tests/i915/gem_mmap_gtt.c
index a5f9d934..4ea54ef1 100644
--- a/tests/i915/gem_mmap_gtt.c
+++ b/tests/i915/gem_mmap_gtt.c
@@ -116,6 +116,20 @@ test_access(int fd)
 			  MAP_SHARED, fd2, mmap_arg.offset));
 }
 
+static void
+test_zero_extend(int i915)
+{
+	struct drm_i915_gem_mmap_gtt arg = {};
+	uint64_t redzone[16];
+
+	memset(redzone, 0xc5, sizeof(redzone));
+	arg.handle = gem_create(i915, 4096);
+
+	igt_assert_eq(ioctl(i915, DRM_IOCTL_I915_GEM_MMAP_GTT, &arg), 0);
+
+	gem_close(i915, arg.handle);
+}
+
 static void
 test_short(int fd)
 {
@@ -1091,6 +1105,8 @@ igt_main
 		test_wc(fd);
 	igt_subtest("isolation")
 		test_isolation(fd);
+	igt_subtest("zero-extend")
+		test_zero_extend(fd);
 	igt_subtest("close-race")
 		test_close_race(fd);
 	igt_subtest("flink-race")
-- 
2.23.0