[Intel-gfx] [PATCH i-g-t v3 2/2] 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.

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 | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)

diff --git a/tests/gem_mmap_gtt.c b/tests/gem_mmap_gtt.c
index 115e398..32d24b4 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 +283,90 @@ 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);
+
+	/* Test read/write to first/last page with CPU. */
+	ptr_cpu = gem_mmap__cpu(fd, bo, 0, huge_object_size,
+				PROT_READ | PROT_WRITE);
+	if (!ptr_cpu) {
+		igt_warn("Not enough free memory to begin huge BO test!\n");
+		goto out;
+	}
+
+	set_domain_cpu(fd, bo);
+
+	memcpy(ptr_cpu, cpu_pattern, PAGE_SIZE);
+	igt_assert(memcmp(ptr_cpu, cpu_pattern, PAGE_SIZE) == 0);
+
+	memcpy(ptr_cpu + last_offset, cpu_pattern, PAGE_SIZE);
+	igt_assert(memcmp(ptr_cpu + last_offset, cpu_pattern, PAGE_SIZE) == 0);
+
+	igt_assert(memcmp(ptr_cpu, ptr_cpu + last_offset, PAGE_SIZE) == 0);
+
+	munmap(ptr_cpu, huge_object_size);
+	ptr_cpu = NULL;
+
+	/* Test read/write to first/last page through GTT after CPU writes.
+	 * Require that previous CPU written values still exist.
+	 */
+	ptr_gtt = gem_mmap__gtt(fd, bo, huge_object_size,
+			        PROT_READ | PROT_WRITE);
+	if (!ptr_gtt) {
+		igt_debug("Huge BO GTT mapping not supported!\n");
+		goto out;
+	}
+
+	set_domain_gtt(fd, bo);
+
+	igt_assert(memcmp(ptr_gtt              , cpu_pattern, PAGE_SIZE) == 0);
+	igt_assert(memcmp(ptr_gtt + last_offset, cpu_pattern, PAGE_SIZE) == 0);
+
+	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);
+
+	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.
+	 * Avoid mapping the object back to CPU domain to avoid 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 +504,8 @@ 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