[Intel-gfx] [PATCH i-g-t] tests/gem_ctx_param: Update invalid param

[Chris Wilson]

Quoting Antonio Argenziano (2017-12-15 19:01:11)
> Since commit: drm/i915/scheduler: Support user-defined priorities, the
> driver support an extra context param to set context's priority. Add
> tests for that interface and update invalid tests.
> 
> Signed-off-by: Antonio Argenziano <antonio.argenziano at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Michal Winiarski <michal.winiarski at intel.com>
> ---
>  tests/gem_ctx_param.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 76 insertions(+), 1 deletion(-)
> 
> diff --git a/tests/gem_ctx_param.c b/tests/gem_ctx_param.c
> index c20ae1ee..9a222e60 100644
> --- a/tests/gem_ctx_param.c
> +++ b/tests/gem_ctx_param.c
> @@ -25,6 +25,7 @@
>   */
>  
>  #include "igt.h"
> +#include <limits.h>
>  
>  IGT_TEST_DESCRIPTION("Basic test for context set/get param input validation.");
>  
> @@ -136,11 +137,85 @@ igt_main
>                 gem_context_set_param(fd, &arg);
>         }
>  
> +#define MAX_PRIO 1023
> +#define MIN_PRIO -MAX_PRIO
> +#define DEF_PRIO 0

Take these from the uapi header.

> +
> +       arg.param = I915_CONTEXT_PARAM_PRIORITY;
> +
> +       igt_subtest("root-set-priority") {
> +               arg.ctx_id = ctx;
> +               arg.size = 0;
> +

Bonus points for CAP_SYS_NICE checking.

arg.size validation checking.
arg.value > u32 (checking for overflows)

gem_context_get_param() of a new context should return DEF_PRIO

set_param on older machines returns -ENODEV

And that's not even trying to fuzz bad values beyond the sanity checks
of I915_CONTEXT_PARAM_PRIORITY.

> +               for (int i = MIN_PRIO; i <= MAX_PRIO; i += 1023) {

It's a couple of ioctls, do all 1024. Do them in a random order, trust
no one.

> +                       arg.value = i;
> +                       gem_context_set_param(fd, &arg);
> +
> +                       gem_context_get_param(fd, &arg);
> +                       igt_assert(arg.value == i); /* Verify prio was set */

igt_assert_eq(arg.value, i);

But doesn't verify the priority does anything. Just the RTT in the API,
which is a nice verification nevertheless.

> +               }
> +       }
> +
> +       igt_subtest("root-set-priority-invalid-value") {
> +               int prio_levels[] = {INT_MIN, MIN_PRIO - 1, MAX_PRIO + 1, INT_MAX};
> +               int old_value;
> +               arg.ctx_id = ctx;
> +
> +               gem_context_get_param(fd, &arg);
> +               old_value = arg.value;
> +
> +               for (int i = 0; i < (sizeof(prio_levels) / sizeof(int)); i++) {

ARRAY_SIZE(prio_levels);

> +                       arg.value = prio_levels[i];
> +                       igt_assert_eq(__gem_context_set_param(fd, &arg), -EINVAL);
> +
> +                       gem_context_get_param(fd, &arg);
> +                       igt_assert(arg.value == old_value); /* Verify prio was not set */
> +               }
> +       }
> +
> +       igt_subtest("user-set-priority") {
> +               arg.size = 0;
> +
> +               igt_fork(child, 1) {
> +                       igt_drop_root();
> +                       for (int i = MIN_PRIO; i <= DEF_PRIO; i += 1023) {
> +                               arg.value = i;
> +                               gem_context_set_param(fd, &arg);
> +
> +                               gem_context_get_param(fd, &arg);
> +                               igt_assert(arg.value == i); /* Verify prio was set */

I wonder if the CAP_SYS_NICE limit might be adjusted in the future.
Certainly preemption rules are flexible, as we haven't told anyone about
them yet.
-Chris