x86/intel_rdt: Enable entering of pseudo-locksetup mode

The user can request entering pseudo-locksetup mode by writing
"pseudo-locksetup" to the mode file. Act on this request as well as
support switching from a pseudo-locksetup mode (before pseudo-locked
mode was entered). It is not supported to modify the mode once
pseudo-locked mode has been entered.

The schemata reflects the new mode by adding "uninitialized" to all
resources. The size resctrl file reports zero for all cache domains in
support of the uninitialized nature. Since there are no users of this
class of service its allocations can be ignored when searching for
appropriate default allocations for new resource groups. For the same
reason resource groups in pseudo-locksetup mode are not considered when
testing if new resource groups may overlap.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/56f553334708022903c296284e62db3bbc1ff150.1529706536.git.reinette.chatre@intel.com

arch/x86/kernel/cpu/intel_rdt_ctrlmondata.c

@@ -156,7 +156,8 @@ int parse_cbm(void *_data, struct rdt_resource *r, struct rdt_domain *d)
 	}
 
 	if (rdtgroup_cbm_overlaps(r, d, cbm_val, rdtgrp->closid, false)) {
-		if (rdtgrp->mode == RDT_MODE_EXCLUSIVE) {
+		if (rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
+		    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
 			rdt_last_cmd_printf("overlaps with other group\n");
 			return -EINVAL;
 		}
@@ -356,10 +357,15 @@ int rdtgroup_schemata_show(struct kernfs_open_file *of,
 
 	rdtgrp = rdtgroup_kn_lock_live(of->kn);
 	if (rdtgrp) {
-		closid = rdtgrp->closid;
-		for_each_alloc_enabled_rdt_resource(r) {
-			if (closid < r->num_closid)
-				show_doms(s, r, closid);
+		if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
+			for_each_alloc_enabled_rdt_resource(r)
+				seq_printf(s, "%s:uninitialized\n", r->name);
+		} else {
+			closid = rdtgrp->closid;
+			for_each_alloc_enabled_rdt_resource(r) {
+				if (closid < r->num_closid)
+					show_doms(s, r, closid);
+			}
 		}
 	} else {
 		ret = -ENOENT;

arch/x86/kernel/cpu/intel_rdt_rdtgroup.c

@@ -974,9 +974,10 @@ bool rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d,
 	ctrl = d->ctrl_val;
 	for (i = 0; i < r->num_closid; i++, ctrl++) {
 		ctrl_b = (unsigned long *)ctrl;
-		if (closid_allocated(i) && i != closid) {
+		mode = rdtgroup_mode_by_closid(i);
+		if (closid_allocated(i) && i != closid &&
+		    mode != RDT_MODE_PSEUDO_LOCKSETUP) {
 			if (bitmap_intersects(cbm, ctrl_b, r->cache.cbm_len)) {
-				mode = rdtgroup_mode_by_closid(i);
 				if (exclusive) {
 					if (mode == RDT_MODE_EXCLUSIVE)
 						return true;
@@ -1046,10 +1047,24 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of,
 	mode = rdtgrp->mode;
 
 	if ((!strcmp(buf, "shareable") && mode == RDT_MODE_SHAREABLE) ||
-	    (!strcmp(buf, "exclusive") && mode == RDT_MODE_EXCLUSIVE))
+	    (!strcmp(buf, "exclusive") && mode == RDT_MODE_EXCLUSIVE) ||
+	    (!strcmp(buf, "pseudo-locksetup") &&
+	     mode == RDT_MODE_PSEUDO_LOCKSETUP) ||
+	    (!strcmp(buf, "pseudo-locked") && mode == RDT_MODE_PSEUDO_LOCKED))
 		goto out;
 
+	if (mode == RDT_MODE_PSEUDO_LOCKED) {
+		rdt_last_cmd_printf("cannot change pseudo-locked group\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
 	if (!strcmp(buf, "shareable")) {
+		if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
+			ret = rdtgroup_locksetup_exit(rdtgrp);
+			if (ret)
+				goto out;
+		}
 		rdtgrp->mode = RDT_MODE_SHAREABLE;
 	} else if (!strcmp(buf, "exclusive")) {
 		if (!rdtgroup_mode_test_exclusive(rdtgrp)) {
@@ -1057,7 +1072,17 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of,
 			ret = -EINVAL;
 			goto out;
 		}
+		if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
+			ret = rdtgroup_locksetup_exit(rdtgrp);
+			if (ret)
+				goto out;
+		}
 		rdtgrp->mode = RDT_MODE_EXCLUSIVE;
+	} else if (!strcmp(buf, "pseudo-locksetup")) {
+		ret = rdtgroup_locksetup_enter(rdtgrp);
+		if (ret)
+			goto out;
+		rdtgrp->mode = RDT_MODE_PSEUDO_LOCKSETUP;
 	} else {
 		rdt_last_cmd_printf("unknown/unsupported mode\n");
 		ret = -EINVAL;
@@ -1127,8 +1152,12 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
 		list_for_each_entry(d, &r->domains, list) {
 			if (sep)
 				seq_putc(s, ';');
-			cbm = d->ctrl_val[rdtgrp->closid];
-			size = rdtgroup_cbm_to_size(r, d, cbm);
+			if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
+				size = 0;
+			} else {
+				cbm = d->ctrl_val[rdtgrp->closid];
+				size = rdtgroup_cbm_to_size(r, d, cbm);
+			}
 			seq_printf(s, "%d=%u", d->id, size);
 			sep = true;
 		}
@@ -2277,6 +2306,8 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
 			for (i = 0; i < r->num_closid; i++, ctrl++) {
 				if (closid_allocated(i) && i != closid) {
 					mode = rdtgroup_mode_by_closid(i);
+					if (mode == RDT_MODE_PSEUDO_LOCKSETUP)
+						break;
 					used_b |= *ctrl;
 					if (mode == RDT_MODE_SHAREABLE)
 						d->new_ctrl |= *ctrl;