[Intel-gfx] [PATCH i-g-t v5] tests/gem_mmap_gtt: add huge BO test

[Joonas Lahtinen]

Add a straightforward test that allocates a BO that is bigger than
(by 1 page currently) the mappable aperture, tests mmap access to it
by CPU directly and through GTT in sequence.

Currently it is expected for the GTT access to gracefully fail as
all objects are attempted to get pinned to GTT completely for mmap
access. Once the partial view support is merged to kernel, the test
should pass for all parts.

v2:
- Corrected BO domain handling (Chris Wilson)
- Check again after GTT access for added paranoia (Chris Wilson)

v3:
- Avoid flush by using pread (Chris Wilson)
- Free gtt_pattern buffer too.

v4:
- Add more comments (Tvrtko Ursulin)
- Use igt_require (Tvrtko Ursulin)

v5:
- Remove wrong message from igt_require_f (Tvrtko Ursulin)
- After digging deeper to it, just igt_assert that the CPU
  mapping needs to succeed.

Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 tests/gem_mmap_gtt.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)

diff --git a/tests/gem_mmap_gtt.c b/tests/gem_mmap_gtt.c
index 115e398..487eecf 100644
--- a/tests/gem_mmap_gtt.c
+++ b/tests/gem_mmap_gtt.c
@@ -41,6 +41,10 @@
 #include "drmtest.h"
 #include "igt_debugfs.h"
 
+#ifndef PAGE_SIZE
+#define PAGE_SIZE 4096
+#endif
+
 static int OBJECT_SIZE = 16*1024*1024;
 
 static void
@@ -55,6 +59,20 @@ set_domain_cpu(int fd, uint32_t handle)
 	gem_set_domain(fd, handle, I915_GEM_DOMAIN_CPU, I915_GEM_DOMAIN_CPU);
 }
 
+static void
+pread_bo(int fd, int handle, void *buf, int offset, int size)
+{
+	struct drm_i915_gem_pread gem_pread;
+
+	memset(&gem_pread, 0, sizeof(gem_pread));
+	gem_pread.handle = handle;
+	gem_pread.data_ptr = (uintptr_t)buf;
+	gem_pread.size = size;
+	gem_pread.offset = offset;
+
+	igt_assert(ioctl(fd, DRM_IOCTL_I915_GEM_PREAD, &gem_pread) == 0);
+}
+
 static void *
 mmap_bo(int fd, uint32_t handle)
 {
@@ -265,6 +283,92 @@ test_write_gtt(int fd)
 }
 
 static void
+test_huge_bo(int fd)
+{
+	uint32_t bo;
+	char *ptr_cpu;
+	char *ptr_gtt;
+	char *cpu_pattern;
+	char *gtt_pattern;
+	uint64_t mappable_aperture_pages = gem_mappable_aperture_size() /
+					   PAGE_SIZE;
+	uint64_t huge_object_size = (mappable_aperture_pages + 1) * PAGE_SIZE;
+	uint64_t last_offset = huge_object_size - PAGE_SIZE;
+
+	cpu_pattern = malloc(PAGE_SIZE);
+	gtt_pattern = malloc(PAGE_SIZE);
+	igt_assert(cpu_pattern && gtt_pattern);
+	memset(cpu_pattern,  0xaa, PAGE_SIZE);
+	memset(gtt_pattern, ~0xaa, PAGE_SIZE);
+
+	bo = gem_create(fd, huge_object_size);
+
+	/* Obtain CPU mapping for the object. */
+	ptr_cpu = gem_mmap__cpu(fd, bo, 0, huge_object_size,
+				PROT_READ | PROT_WRITE);
+	igt_assert(ptr_cpu);
+
+	set_domain_cpu(fd, bo);
+
+	/* Write first page through the mapping and assert reading it back
+	 * works. */
+	memcpy(ptr_cpu, cpu_pattern, PAGE_SIZE);
+	igt_assert(memcmp(ptr_cpu, cpu_pattern, PAGE_SIZE) == 0);
+
+	/* Write last page through the mapping and assert reading it back
+	 * works. */
+	memcpy(ptr_cpu + last_offset, cpu_pattern, PAGE_SIZE);
+	igt_assert(memcmp(ptr_cpu + last_offset, cpu_pattern, PAGE_SIZE) == 0);
+
+	/* Cross check that accessing two simultaneous pages works. */
+	igt_assert(memcmp(ptr_cpu, ptr_cpu + last_offset, PAGE_SIZE) == 0);
+
+	munmap(ptr_cpu, huge_object_size);
+	ptr_cpu = NULL;
+
+	/* Obtain mapping for the object through GTT. */
+	ptr_gtt = gem_mmap__gtt(fd, bo, huge_object_size,
+			        PROT_READ | PROT_WRITE);
+	igt_require_f(ptr_gtt, "Huge BO GTT mapping not supported.\n");
+
+	set_domain_gtt(fd, bo);
+
+	/* Access through GTT should still provide the CPU written values. */
+	igt_assert(memcmp(ptr_gtt              , cpu_pattern, PAGE_SIZE) == 0);
+	igt_assert(memcmp(ptr_gtt + last_offset, cpu_pattern, PAGE_SIZE) == 0);
+
+	/* Try replacing first page through GTT mapping and make sure other page
+	 * stays intact. */
+	memcpy(ptr_gtt, gtt_pattern, PAGE_SIZE);
+	igt_assert(memcmp(ptr_gtt              , gtt_pattern, PAGE_SIZE) == 0);
+	igt_assert(memcmp(ptr_gtt + last_offset, cpu_pattern, PAGE_SIZE) == 0);
+
+	/* And make sure that after writing, both pages contain what they
+	 * should.*/
+	memcpy(ptr_gtt + last_offset, gtt_pattern, PAGE_SIZE);
+	igt_assert(memcmp(ptr_gtt              , gtt_pattern, PAGE_SIZE) == 0);
+	igt_assert(memcmp(ptr_gtt + last_offset, gtt_pattern, PAGE_SIZE) == 0);
+
+	munmap(ptr_gtt, huge_object_size);
+	ptr_gtt = NULL;
+
+	/* Verify the page contents after GTT writes by reading without mapping.
+	 * Mapping to CPU domain is avoided not to cause a huge flush.
+	 */
+	pread_bo(fd, bo, cpu_pattern, 0, PAGE_SIZE);
+	igt_assert(memcmp(cpu_pattern, gtt_pattern, PAGE_SIZE) == 0);
+
+	memset(cpu_pattern, 0x00, PAGE_SIZE);
+
+	pread_bo(fd, bo, cpu_pattern, last_offset, PAGE_SIZE);
+	igt_assert(memcmp(cpu_pattern, gtt_pattern, PAGE_SIZE) == 0);
+out:
+	gem_close(fd, bo);
+	free(cpu_pattern);
+	free(gtt_pattern);
+}
+
+static void
 test_read(int fd)
 {
 	void *dst;
@@ -402,6 +506,8 @@ igt_main
 		run_without_prefault(fd, test_write_gtt);
 	igt_subtest("write-cpu-read-gtt")
 		test_write_cpu_read_gtt(fd);
+	igt_subtest("huge-bo")
+		test_huge_bo(fd);
 
 	igt_fixture
 		close(fd);
-- 
1.9.3