Commit 52a4edb1 authored by James Morse's avatar James Morse
Browse files

arm_mpam: resctrl: Pick the caches we will use as resctrl resources 



Systems with MPAM support may have a variety of control types at any point
of their system layout. We can only expose certain types of control, and
only if they exist at particular locations.

Start with the well-known caches. These have to be depth 2 or 3 and support
MPAM's cache portion bitmap controls, with a number of portions fewer than
resctrl's limit.

Tested-by: default avatarGavin Shan <gshan@redhat.com>
Tested-by: default avatarShaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: default avatarPeter Newman <peternewman@google.com>
Tested-by: default avatarZeng Heng <zengheng4@huawei.com>
Tested-by: default avatarPunit Agrawal <punit.agrawal@oss.qualcomm.com>
Tested-by: default avatarJesse Chick <jessechick@os.amperecomputing.com>
Reviewed-by: default avatarZeng Heng <zengheng4@huawei.com>
Reviewed-by: default avatarShaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: default avatarJonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Co-developed-by: default avatarBen Horgan <ben.horgan@arm.com>
Signed-off-by: default avatarBen Horgan <ben.horgan@arm.com>
Signed-off-by: default avatarJames Morse <james.morse@arm.com>
parent 09e61daf

drivers/resctrl/mpam_resctrl.c

+89 −2
Original line number Diff line number Diff line
@@ -65,9 +65,95 @@ struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l) 
	return &mpam_resctrl_controls[l].resctrl_res;

}



static bool cache_has_usable_cpor(struct mpam_class *class)

{

	struct mpam_props *cprops = &class->props;



	if (!mpam_has_feature(mpam_feat_cpor_part, cprops))

		return false;



	/* resctrl uses u32 for all bitmap configurations */

	return class->props.cpbm_wd <= 32;

}



/* Test whether we can export MPAM_CLASS_CACHE:{2,3}? */

static void mpam_resctrl_pick_caches(void)

{

	struct mpam_class *class;

	struct mpam_resctrl_res *res;



	lockdep_assert_cpus_held();



	guard(srcu)(&mpam_srcu);

	list_for_each_entry_srcu(class, &mpam_classes, classes_list,

				 srcu_read_lock_held(&mpam_srcu)) {

		if (class->type != MPAM_CLASS_CACHE) {

			pr_debug("class %u is not a cache\n", class->level);

			continue;

		}



		if (class->level != 2 && class->level != 3) {

			pr_debug("class %u is not L2 or L3\n", class->level);

			continue;

		}



		if (!cache_has_usable_cpor(class)) {

			pr_debug("class %u cache misses CPOR\n", class->level);

			continue;

		}



		if (!cpumask_equal(&class->affinity, cpu_possible_mask)) {

			pr_debug("class %u has missing CPUs, mask %*pb != %*pb\n", class->level,

				 cpumask_pr_args(&class->affinity),

				 cpumask_pr_args(cpu_possible_mask));

			continue;

		}



		if (class->level == 2)

			res = &mpam_resctrl_controls[RDT_RESOURCE_L2];

		else

			res = &mpam_resctrl_controls[RDT_RESOURCE_L3];

		res->class = class;

	}

}



static int mpam_resctrl_control_init(struct mpam_resctrl_res *res)

{

	/* TODO: initialise the resctrl resources */

	struct mpam_class *class = res->class;

	struct rdt_resource *r = &res->resctrl_res;



	switch (r->rid) {

	case RDT_RESOURCE_L2:

	case RDT_RESOURCE_L3:

		r->schema_fmt = RESCTRL_SCHEMA_BITMAP;

		r->cache.arch_has_sparse_bitmasks = true;



		r->cache.cbm_len = class->props.cpbm_wd;

		/* mpam_devices will reject empty bitmaps */

		r->cache.min_cbm_bits = 1;



		if (r->rid == RDT_RESOURCE_L2) {

			r->name = "L2";

			r->ctrl_scope = RESCTRL_L2_CACHE;

			r->cdp_capable = true;

		} else {

			r->name = "L3";

			r->ctrl_scope = RESCTRL_L3_CACHE;

			r->cdp_capable = true;

		}



		/*

		 * Which bits are shared with other ...things...  Unknown

		 * devices use partid-0 which uses all the bitmap fields. Until

		 * we have configured the SMMU and GIC not to do this 'all the

		 * bits' is the correct answer here.

		 */

		r->cache.shareable_bits = resctrl_get_default_ctrl(r);

		r->alloc_capable = true;

		break;

	default:

		return -EINVAL;

	}



	return 0;

}
@@ -292,7 +378,8 @@ int mpam_resctrl_setup(void) 
		res->resctrl_res.rid = rid;

	}



	/* TODO: pick MPAM classes to map to resctrl resources */

	/* Find some classes to use for controls */

	mpam_resctrl_pick_caches();



	/* Initialise the resctrl structures from the classes */

	for_each_mpam_resctrl_control(res, rid) {