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

[Tiago Vignatti]

On 08/13/2015 04:01 AM, Daniel Vetter wrote:
> 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 at intel.com>
>
> Squash with previous patch?

why? if the whole point is to decrease the amount of patches, then I 
prefer to squash 2/7 with the 1/7 (although they're from different 
authors and would be nice to keep separately the changes from each). 
This patch here introduces this writing to mmap'ed dma-buf fd, a concept 
that is still in debate, requiring a kernel counter-part so that's why I 
preferred to keep it away.


>> ---
>>   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.

true. Thank you.


> -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
>>
>