Re: [PATCH 3/7] prime_mmap: Add basic tests to write in a bo using CPU

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Aug 12, 2015 at 08:29:16PM -0300, Tiago Vignatti wrote:
> This patch adds test_correct_cpu_write, which maps the texture buffer through a
> prime fd and then writes directly to it using the CPU. It stresses the driver
> to guarantee cache synchronization among the different domains.
> 
> This test also adds test_forked_cpu_write, which creates the GEM bo in one
> process and pass the prime handle of the it to another process, which in turn
> uses the handle only to map and write. Grossly speaking this test simulates
> Chrome OS  architecture, where the Web content ("unpriviledged process") maps
> and CPU-draws a buffer, which was previously allocated in the GPU process
> ("priviledged process").
> 
> This requires kernel modifications (Daniel Thompson's "drm: prime: Honour
> O_RDWR during prime-handle-to-fd").
> 
> Signed-off-by: Tiago Vignatti <tiago.vignatti@intel.com>

Squash with previous patch?
> ---
>  lib/ioctl_wrappers.c |  5 +++-
>  tests/prime_mmap.c   | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 69 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/ioctl_wrappers.c b/lib/ioctl_wrappers.c
> index 53bd635..941fa66 100644
> --- a/lib/ioctl_wrappers.c
> +++ b/lib/ioctl_wrappers.c
> @@ -1125,6 +1125,9 @@ void gem_require_ring(int fd, int ring_id)
>  
>  /* prime */
>  
> +#ifndef DRM_RDWR
> +#define DRM_RDWR O_RDWR
> +#endif
>  /**
>   * prime_handle_to_fd:
>   * @fd: open i915 drm file descriptor
> @@ -1142,7 +1145,7 @@ int prime_handle_to_fd(int fd, uint32_t handle)
>  
>  	memset(&args, 0, sizeof(args));
>  	args.handle = handle;
> -	args.flags = DRM_CLOEXEC;
> +	args.flags = DRM_CLOEXEC | DRM_RDWR;

This needs to be optional otherwise all the existing prime tests start
falling over on older kernels. Probably need a
prime_handle_to_fd_with_mmap, which doesn an igt_skip if it fails.
-Daniel

>  	args.fd = -1;
>  
>  	do_ioctl(fd, DRM_IOCTL_PRIME_HANDLE_TO_FD, &args);
> diff --git a/tests/prime_mmap.c b/tests/prime_mmap.c
> index dc59e8f..ad91371 100644
> --- a/tests/prime_mmap.c
> +++ b/tests/prime_mmap.c
> @@ -22,6 +22,7 @@
>   *
>   * Authors:
>   *    Rob Bradford <rob at linux.intel.com>
> + *    Tiago Vignatti <tiago.vignatti at intel.com>
>   *
>   */
>  
> @@ -66,6 +67,12 @@ fill_bo(uint32_t handle, size_t size)
>  }
>  
>  static void
> +fill_bo_cpu(char *ptr)
> +{
> +	memcpy(ptr, pattern, sizeof(pattern));
> +}
> +
> +static void
>  test_correct(void)
>  {
>  	int dma_buf_fd;
> @@ -180,6 +187,62 @@ test_forked(void)
>  	gem_close(fd, handle);
>  }
>  
> +/* test CPU write. This has a rather big implication for the driver which must
> + * guarantee cache synchronization when writing the bo using CPU. */
> +static void
> +test_correct_cpu_write(void)
> +{
> +	int dma_buf_fd;
> +	char *ptr;
> +	uint32_t handle;
> +
> +	handle = gem_create(fd, BO_SIZE);
> +
> +	dma_buf_fd = prime_handle_to_fd(fd, handle);
> +	igt_assert(errno == 0);
> +
> +	/* Check correctness of map using write protection (PROT_WRITE) */
> +	ptr = mmap(NULL, BO_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, dma_buf_fd, 0);
> +	igt_assert(ptr != MAP_FAILED);
> +
> +	/* Fill bo using CPU */
> +	fill_bo_cpu(ptr);
> +
> +	/* Check pattern correctness */
> +	igt_assert(memcmp(ptr, pattern, sizeof(pattern)) == 0);
> +
> +	munmap(ptr, BO_SIZE);
> +	close(dma_buf_fd);
> +	gem_close(fd, handle);
> +}
> +
> +/* map from another process and then write using CPU */
> +static void
> +test_forked_cpu_write(void)
> +{
> +	int dma_buf_fd;
> +	char *ptr;
> +	uint32_t handle;
> +
> +	handle = gem_create(fd, BO_SIZE);
> +
> +	dma_buf_fd = prime_handle_to_fd(fd, handle);
> +	igt_assert(errno == 0);
> +
> +	igt_fork(childno, 1) {
> +		ptr = mmap(NULL, BO_SIZE, PROT_READ | PROT_WRITE , MAP_SHARED, dma_buf_fd, 0);
> +		igt_assert(ptr != MAP_FAILED);
> +		fill_bo_cpu(ptr);
> +
> +		igt_assert(memcmp(ptr, pattern, sizeof(pattern)) == 0);
> +		munmap(ptr, BO_SIZE);
> +		close(dma_buf_fd);
> +	}
> +	close(dma_buf_fd);
> +	igt_waitchildren();
> +	gem_close(fd, handle);
> +}
> +
>  static void
>  test_refcounting(void)
>  {
> @@ -346,6 +409,8 @@ igt_main
>  		{ "test_map_unmap", test_map_unmap },
>  		{ "test_reprime", test_reprime },
>  		{ "test_forked", test_forked },
> +		{ "test_correct_cpu_write", test_correct_cpu_write },
> +		{ "test_forked_cpu_write", test_forked_cpu_write },
>  		{ "test_refcounting", test_refcounting },
>  		{ "test_dup", test_dup },
>  		{ "test_errors", test_errors },
> -- 
> 2.1.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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