Re: [PATCH] tests/intel/xe_exec_system_allocator: Skip reserved PAT madvise indices

[Gustavo Sousa <gustavo.sousa@intel.com>]

<nishit.sharma@intel.com> writes:

> From: Nishit Sharma <nishit.sharma@intel.com>
>
> KMD may mark some PAT entries as reserved in the debugfs pat_sw_config
> dump (e.g. Wa_14026539277 reserves the 2-way-coherent entries), and
> such entries must not be used. Skip the PAT-index madvise subtests when
> the selected PAT index is reserved instead of decoding the coherency
> bits of the PAT entry.
>
> Always read the PAT software configuration rather than only when a
> specific workaround is active, so that any future reservation is
> honoured as well. Kernels that don't expose pat_sw_config have no
> reserved entries to report, so every index is treated as usable there.
>
> v2:
> - Read pat_sw_config unconditionally (Gustavo)
> - Don't mention Wa_14026539277 in the skip message (Gustavo)
>
> Signed-off-by: Nishit Sharma <nishit.sharma@intel.com>

Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>

> ---
>  tests/intel/xe_exec_system_allocator.c | 32 ++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)
>
> diff --git a/tests/intel/xe_exec_system_allocator.c b/tests/intel/xe_exec_system_allocator.c
> index 45ec62813..c6a8872b4 100644
> --- a/tests/intel/xe_exec_system_allocator.c
> +++ b/tests/intel/xe_exec_system_allocator.c
> @@ -1216,6 +1216,16 @@ xe_vm_madvixe_pat_attr(int fd, uint32_t vm, uint64_t addr, uint64_t range,
>  		      DRM_XE_MEM_RANGE_ATTR_PAT, pat_index, 0, 0);
>  }
>  
> +static bool pat_idx_is_reserved(const struct intel_pat_cache *pat_sw_config,
> +				int32_t num_pat_entries,
> +				uint8_t pat_idx)
> +{
> +	if (pat_idx >= num_pat_entries)
> +		return false;
> +
> +	return pat_sw_config->entries[pat_idx].rsvd;
> +}
> +
>  static void
>  xe_vm_madvise_atomic_attr(int fd, uint32_t vm, uint64_t addr, uint64_t range,
>  			  int mem_attr)
> @@ -2647,6 +2657,8 @@ int igt_main()
>  
>  	int fd, svm_compute_loops = getenv_int("IGT_SVM_COMPUTE_LOOPS", 1);
>  	uint16_t dev_id;
> +	struct intel_pat_cache pat_sw_config = {};
> +	int32_t num_pat_entries = 0;
>  
>  	igt_fixture() {
>  		struct xe_device *xe;
> @@ -2658,6 +2670,19 @@ int igt_main()
>  		va_bits = xe->va_bits;
>  		open_sync_file();
>  		dev_id = intel_get_drm_devid(fd);
> +
> +		/*
> +		 * KMD may mark PAT entries as reserved for various reasons
> +		 * (e.g. workarounds). Older kernels without the debugfs
> +		 * pat_sw_config entry don't expose that information, so
> +		 * treat every index as usable in that case.
> +		 */
> +		num_pat_entries = xe_get_pat_sw_config(fd, &pat_sw_config, 0);
> +		if (num_pat_entries <= 0) {
> +			igt_debug("Couldn't get Xe PAT software configuration (%d)\n",
> +				  num_pat_entries);
> +			num_pat_entries = 0;
> +		}
>  	}
>  
>  	for (const struct section *s = sections; s->name; s++) {
> @@ -2879,6 +2904,8 @@ int igt_main()
>  
>  	for (const struct section *s = intel_get_pat_idx_functions; s->name; s++) {
>  		igt_subtest_f("pat-index-%s", s->name) {
> +			uint8_t pat_idx;
> +
>  			if ((strstr(s->name, "madvise-pat-idx-wt-") ||
>  			     strstr(s->name, "madvise-pat-idx-uc-comp-")) &&
>  			     !xe_has_vram(fd)) {
> @@ -2887,6 +2914,11 @@ int igt_main()
>  			if (IS_PONTEVECCHIO(dev_id) &&
>  			    strstr(s->name, "madvise-pat-idx-uc-comp-"))
>  				igt_skip("Skipping compression-related PAT index on PVC\n");
> +
> +			pat_idx = s->fn(fd);
> +			igt_skip_on_f(pat_idx_is_reserved(&pat_sw_config, num_pat_entries,
> +							  pat_idx),
> +				      "PAT index %u is reserved\n", pat_idx);
>  			xe_for_each_engine(fd, hwe)
>  				test_exec(fd, hwe, 1, 1, SZ_4M, 0, 0, NULL, NULL, s->flags, s->fn);
>  		}
> -- 
> 2.43.0