On Thu, 14 Feb 2019 at 18:32, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
>
> The kernel must not return stale information back to userspace when they
> create a new object. For that purpose, we always clear objects on
> creation, so verify that this is so.
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
> ---
> tests/i915/gem_create.c | 71 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 71 insertions(+)
>
> diff --git a/tests/i915/gem_create.c b/tests/i915/gem_create.c
> index 25c5e8088..9de2263d5 100644
> --- a/tests/i915/gem_create.c
> +++ b/tests/i915/gem_create.c
> @@ -44,6 +44,7 @@
> #include <sys/stat.h>
> #include <sys/time.h>
> #include <getopt.h>
> +#include <pthread.h>
>
> #include <drm.h>
>
> @@ -141,6 +142,73 @@ static void invalid_nonaligned_size(int fd)
> gem_close(fd, handle);
> }
>
> +static uint64_t get_npages(uint64_t *global, uint64_t npages)
> +{
> + uint64_t try, old, max;
> +
> + max = *global;
> + do {
> + old = max;
> + try = npages % (max / 2);
> + max -= try;
> + } while ((max = __sync_val_compare_and_swap(global, old, max)) != old);
> +
> + return try;
> +}
> +
> +struct thread_clear {
> + uint64_t max;
> + int timeout;
> + int i915;
> +};
> +
> +static void *thread_clear(void *data)
> +{
> + struct thread_clear *arg = data;
> + int i915 = arg->i915;
> +
> + igt_until_timeout(arg->timeout) {
> + uint32_t handle;
> + uint64_t npages;
> +
> + npages = random();
> + npages <<= 32;
> + npages |= random();
> + npages = get_npages(&arg->max, npages);
> +
> + handle = gem_create(i915, npages << 12);
> + for (uint64_t page = 0; page < npages; page++) {
> + uint64_t x;
> +
> + gem_read(i915, handle,
> + page % (4096 - sizeof(x)),
> + &x, sizeof(x));
Don't we also want to read some values outside of the first page, or
am I missing something?
> + igt_assert_eq_u64(x, 0);
> + }
> + gem_close(i915, handle);
> +
> + __sync_add_and_fetch(&arg->max, npages);
> + }
> +
> + return NULL;
> +}
> +
> +static void always_clear(int i915, int timeout)
> +{
> + struct thread_clear arg = {
> + .i915 = i915,
> + .timeout = timeout,
> + .max = intel_get_avail_ram_mb() << (20 - 12), /* in pages */
> + };
> + const int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
> + pthread_t thread[ncpus];
> +
> + for (int i = 0; i < ncpus; i++)
> + pthread_create(&thread[i], NULL, thread_clear, &arg);
> + for (int i = 0; i < ncpus; i++)
> + pthread_join(thread[i], NULL);
> +}
> +
> igt_main
> {
> int fd = -1;
> @@ -162,4 +230,7 @@ igt_main
>
> igt_subtest("create-invalid-nonaligned")
> invalid_nonaligned_size(fd);
> +
> + igt_subtest("create-clear")
> + always_clear(fd, 30);
> }
> --
> 2.20.1
>
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