[PATCH i-g-t] i915/gem_mmap_offset: Partial mmap and munmap

[Nirmoy Das]

On 4/12/2024 2:42 AM, Andi Shyti wrote:
> From: Chris Wilson <chris.p.wilson at linux.intel.com>
>
> Based on a test case developed by Lionel Landwerlin, this exercises
> creation of partial mmaps using both direct methods of a partial mmap()
> (where the mmap() only covers a portion of the object) and
> munmap() to do the same.
>
> Signed-off-by: Chris Wilson <chris.p.wilson at linux.intel.com>
> Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
> ---
>   tests/intel/gem_mmap_offset.c | 84 +++++++++++++++++++++++++++++++++++
>   1 file changed, 84 insertions(+)
>
> diff --git a/tests/intel/gem_mmap_offset.c b/tests/intel/gem_mmap_offset.c
> index 95d2158ca88f..0ba2f9591f85 100644
> --- a/tests/intel/gem_mmap_offset.c
> +++ b/tests/intel/gem_mmap_offset.c
> @@ -56,6 +56,8 @@
>    * SUBTEST: isolation
>    * SUBTEST: oob-read
>    * SUBTEST: open-flood
> + * SUBTEST: partial-mmap
> + * SUBTEST: partial-unmap
>    * SUBTEST: perf
>    * SUBTEST: pf-nonblock
>    * SUBTEST: ptrace
> @@ -874,6 +876,83 @@ static void blt_coherency(int i915)
>   	igt_assert_f(compare_ok, "Problem with coherency, flush is too late\n");
>   }
>   
> +static void partial_mmap(int i915)
> +{
> +	uint32_t handle;
> +
> +	handle = gem_create(i915, SZ_2M);
> +
> +	for_each_mmap_offset_type(i915, t) {
> +		struct drm_i915_gem_mmap_offset arg = {
> +			.handle = handle,
> +			.flags = t->type,
> +		};
> +		uint32_t *ptr;
> +
> +		if (mmap_offset_ioctl(i915, &arg))
> +			continue;
> +
> +		ptr = mmap(0, SZ_4K, PROT_WRITE, MAP_SHARED, i915, arg.offset);
> +		if (ptr == MAP_FAILED)
> +			continue;
> +
> +		memset(ptr, 0xcc, SZ_4K);
> +		munmap(ptr, SZ_4K);
> +
> +		ptr = mmap(0, SZ_4K, PROT_READ, MAP_SHARED, i915, arg.offset + SZ_2M - SZ_4K);
> +		igt_assert(ptr != MAP_FAILED);
> +
> +		for (uint32_t i = 0; i < SZ_4K / sizeof(uint32_t); i++)
> +			igt_assert_eq_u32(ptr[i], 0);
> +
> +		munmap(ptr, SZ_4K);
> +	}
> +
> +	gem_close(i915, handle);
> +}
> +
> +static void partial_unmap(int i915)
> +{
> +	uint32_t handle;
> +
> +	handle = gem_create(i915, SZ_2M);
> +
> +	for_each_mmap_offset_type(i915, t) {
> +		uint8_t *ptr_a, *ptr_b;
> +
> +		/* mmap the same GEM BO twice */
> +		ptr_a = __mmap_offset(i915, handle, 0, SZ_2M,
> +				PROT_READ | PROT_WRITE,
> +				t->type);
> +		if (!ptr_a)
> +			continue;
> +
> +		ptr_b = __mmap_offset(i915, handle, 0, SZ_2M,
> +				PROT_READ | PROT_WRITE,
> +				t->type);
> +		if (!ptr_b)
> +			continue;
> +
> +		/* unmap the first mapping but the last 4k */
> +		munmap(ptr_a, SZ_2M - SZ_4K);
> +
> +		/* memset that remaining 4k with 0xcc */
> +		memset(ptr_a + SZ_2M - SZ_4K, 0xcc, SZ_4K);
> +
> +		/* memset the first page of the 2Mb with 0xdd */
> +		memset(ptr_b, 0xdd, SZ_4K);
> +
> +		for (uint32_t i = 0; i < SZ_4K; i++)
> +			igt_assert_eq_u32(ptr_a[SZ_2M - SZ_4K + i], 0xcc);
> +
> +		munmap(ptr_a + SZ_2M - SZ_4K, SZ_4K);
> +		memset(ptr_b, 0, SZ_2M);

Do we need this extra memset() ? Otherwise

Reviewed-by: Nirmoy Das <nirmoy.das at intel.com>


> +		munmap(ptr_b, SZ_2M);
> +	}
> +
> +	gem_close(i915, handle);
> +}
> +
>   static int mmap_gtt_version(int i915)
>   {
>   	int gtt_version = -1;
> @@ -931,6 +1010,11 @@ igt_main
>   	igt_subtest_f("open-flood")
>   		open_flood(i915, 20);
>   
> +	igt_subtest_f("partial-mmap")
> +		partial_mmap(i915);
> +	igt_subtest_f("partial-unmap")
> +		partial_unmap(i915);
> +
>   	igt_subtest_with_dynamic("clear") {
>   		for_each_memory_region(r, i915) {
>   			igt_dynamic_f("%s", r->name)