1 files changed, 178 insertions, 126 deletions

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 0ec30b2384c0..10d8f5cbb510 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -393,82 +393,86 @@ unlock:
 	return ret ?: nbytes;
 }
 
-struct task_move_callback {
-	struct callback_head	work;
-	struct rdtgroup		*rdtgrp;
-};
-
-static void move_myself(struct callback_head *head)
+/**
+ * rdtgroup_remove - the helper to remove resource group safely
+ * @rdtgrp: resource group to remove
+ *
+ * On resource group creation via a mkdir, an extra kernfs_node reference is
+ * taken to ensure that the rdtgroup structure remains accessible for the
+ * rdtgroup_kn_unlock() calls where it is removed.
+ *
+ * Drop the extra reference here, then free the rdtgroup structure.
+ *
+ * Return: void
+ */
+static void rdtgroup_remove(struct rdtgroup *rdtgrp)
 {
-	struct task_move_callback *callback;
-	struct rdtgroup *rdtgrp;
-
-	callback = container_of(head, struct task_move_callback, work);
-	rdtgrp = callback->rdtgrp;
+	kernfs_put(rdtgrp->kn);
+	kfree(rdtgrp);
+}
 
+static void _update_task_closid_rmid(void *task)
+{
 	/*
-	 * If resource group was deleted before this task work callback
-	 * was invoked, then assign the task to root group and free the
-	 * resource group.
+	 * If the task is still current on this CPU, update PQR_ASSOC MSR.
+	 * Otherwise, the MSR is updated when the task is scheduled in.
 	 */
-	if (atomic_dec_and_test(&rdtgrp->waitcount) &&
-	    (rdtgrp->flags & RDT_DELETED)) {
-		current->closid = 0;
-		current->rmid = 0;
-		kfree(rdtgrp);
-	}
-
-	preempt_disable();
-	/* update PQR_ASSOC MSR to make resource group go into effect */
-	intel_rdt_sched_in();
-	preempt_enable();
+	if (task == current)
+		intel_rdt_sched_in();
+}
 
-	kfree(callback);
+static void update_task_closid_rmid(struct task_struct *t)
+{
+	if (IS_ENABLED(CONFIG_SMP) && task_curr(t))
+		smp_call_function_single(task_cpu(t), _update_task_closid_rmid, t, 1);
+	else
+		_update_task_closid_rmid(t);
 }
 
 static int __rdtgroup_move_task(struct task_struct *tsk,
 				struct rdtgroup *rdtgrp)
 {
-	struct task_move_callback *callback;
-	int ret;
-
-	callback = kzalloc(sizeof(*callback), GFP_KERNEL);
-	if (!callback)
-		return -ENOMEM;
-	callback->work.func = move_myself;
-	callback->rdtgrp = rdtgrp;
+	/* If the task is already in rdtgrp, no need to move the task. */
+	if ((rdtgrp->type == RDTCTRL_GROUP && tsk->closid == rdtgrp->closid &&
+	     tsk->rmid == rdtgrp->mon.rmid) ||
+	    (rdtgrp->type == RDTMON_GROUP && tsk->rmid == rdtgrp->mon.rmid &&
+	     tsk->closid == rdtgrp->mon.parent->closid))
+		return 0;
 
 	/*
-	 * Take a refcount, so rdtgrp cannot be freed before the
-	 * callback has been invoked.
+	 * Set the task's closid/rmid before the PQR_ASSOC MSR can be
+	 * updated by them.
+	 *
+	 * For ctrl_mon groups, move both closid and rmid.
+	 * For monitor groups, can move the tasks only from
+	 * their parent CTRL group.
 	 */
-	atomic_inc(&rdtgrp->waitcount);
-	ret = task_work_add(tsk, &callback->work, true);
-	if (ret) {
-		/*
-		 * Task is exiting. Drop the refcount and free the callback.
-		 * No need to check the refcount as the group cannot be
-		 * deleted before the write function unlocks rdtgroup_mutex.
-		 */
-		atomic_dec(&rdtgrp->waitcount);
-		kfree(callback);
-	} else {
-		/*
-		 * For ctrl_mon groups move both closid and rmid.
-		 * For monitor groups, can move the tasks only from
-		 * their parent CTRL group.
-		 */
-		if (rdtgrp->type == RDTCTRL_GROUP) {
-			tsk->closid = rdtgrp->closid;
+
+	if (rdtgrp->type == RDTCTRL_GROUP) {
+		tsk->closid = rdtgrp->closid;
+		tsk->rmid = rdtgrp->mon.rmid;
+	} else if (rdtgrp->type == RDTMON_GROUP) {
+		if (rdtgrp->mon.parent->closid == tsk->closid)
 			tsk->rmid = rdtgrp->mon.rmid;
-		} else if (rdtgrp->type == RDTMON_GROUP) {
-			if (rdtgrp->mon.parent->closid == tsk->closid)
-				tsk->rmid = rdtgrp->mon.rmid;
-			else
-				ret = -EINVAL;
-		}
+		else
+			return -EINVAL;
 	}
-	return ret;
+
+	/*
+	 * Ensure the task's closid and rmid are written before determining if
+	 * the task is current that will decide if it will be interrupted.
+	 */
+	barrier();
+
+	/*
+	 * By now, the task's closid and rmid are set. If the task is current
+	 * on a CPU, the PQR_ASSOC MSR needs to be updated to make the resource
+	 * group go into effect. If the task is not current, the MSR will be
+	 * updated when the task is scheduled in.
+	 */
+	update_task_closid_rmid(tsk);
+
+	return 0;
 }
 
 static int rdtgroup_task_write_permission(struct task_struct *task,
@@ -830,7 +834,6 @@ static int rdtgroup_mkdir_info_resdir(struct rdt_resource *r, char *name,
 	if (IS_ERR(kn_subdir))
 		return PTR_ERR(kn_subdir);
 
-	kernfs_get(kn_subdir);
 	ret = rdtgroup_kn_set_ugid(kn_subdir);
 	if (ret)
 		return ret;
@@ -853,7 +856,6 @@ static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 	kn_info = kernfs_create_dir(parent_kn, "info", parent_kn->mode, NULL);
 	if (IS_ERR(kn_info))
 		return PTR_ERR(kn_info);
-	kernfs_get(kn_info);
 
 	for_each_alloc_enabled_rdt_resource(r) {
 		fflags =  r->fflags | RF_CTRL_INFO;
@@ -870,12 +872,6 @@ static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 			goto out_destroy;
 	}
 
-	/*
-	 * This extra ref will be put in kernfs_remove() and guarantees
-	 * that @rdtgrp->kn is always accessible.
-	 */
-	kernfs_get(kn_info);
-
 	ret = rdtgroup_kn_set_ugid(kn_info);
 	if (ret)
 		goto out_destroy;
@@ -904,12 +900,6 @@ mongroup_create_dir(struct kernfs_node *parent_kn, struct rdtgroup *prgrp,
 	if (dest_kn)
 		*dest_kn = kn;
 
-	/*
-	 * This extra ref will be put in kernfs_remove() and guarantees
-	 * that @rdtgrp->kn is always accessible.
-	 */
-	kernfs_get(kn);
-
 	ret = rdtgroup_kn_set_ugid(kn);
 	if (ret)
 		goto out_destroy;
@@ -922,6 +912,7 @@ out_destroy:
 	kernfs_remove(kn);
 	return ret;
 }
+
 static void l3_qos_cfg_update(void *arg)
 {
 	bool *enable = arg;
@@ -929,8 +920,17 @@ static void l3_qos_cfg_update(void *arg)
 	wrmsrl(IA32_L3_QOS_CFG, *enable ? L3_QOS_CDP_ENABLE : 0ULL);
 }
 
-static int set_l3_qos_cfg(struct rdt_resource *r, bool enable)
+static void l2_qos_cfg_update(void *arg)
 {
+	bool *enable = arg;
+
+	wrmsrl(IA32_L2_QOS_CFG, *enable ? L2_QOS_CDP_ENABLE : 0ULL);
+}
+
+static int set_cache_qos_cfg(int level, bool enable)
+{
+	void (*update)(void *arg);
+	struct rdt_resource *r_l;
 	cpumask_var_t cpu_mask;
 	struct rdt_domain *d;
 	int cpu;
@@ -938,16 +938,24 @@ static int set_l3_qos_cfg(struct rdt_resource *r, bool enable)
 	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
 		return -ENOMEM;
 
-	list_for_each_entry(d, &r->domains, list) {
+	if (level == RDT_RESOURCE_L3)
+		update = l3_qos_cfg_update;
+	else if (level == RDT_RESOURCE_L2)
+		update = l2_qos_cfg_update;
+	else
+		return -EINVAL;
+
+	r_l = &rdt_resources_all[level];
+	list_for_each_entry(d, &r_l->domains, list) {
 		/* Pick one CPU from each domain instance to update MSR */
 		cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
 	}
 	cpu = get_cpu();
 	/* Update QOS_CFG MSR on this cpu if it's in cpu_mask. */
 	if (cpumask_test_cpu(cpu, cpu_mask))
-		l3_qos_cfg_update(&enable);
+		update(&enable);
 	/* Update QOS_CFG MSR on all other cpus in cpu_mask. */
-	smp_call_function_many(cpu_mask, l3_qos_cfg_update, &enable, 1);
+	smp_call_function_many(cpu_mask, update, &enable, 1);
 	put_cpu();
 
 	free_cpumask_var(cpu_mask);
@@ -955,52 +963,99 @@ static int set_l3_qos_cfg(struct rdt_resource *r, bool enable)
 	return 0;
 }
 
-static int cdp_enable(void)
+static int cdp_enable(int level, int data_type, int code_type)
 {
-	struct rdt_resource *r_l3data = &rdt_resources_all[RDT_RESOURCE_L3DATA];
-	struct rdt_resource *r_l3code = &rdt_resources_all[RDT_RESOURCE_L3CODE];
-	struct rdt_resource *r_l3 = &rdt_resources_all[RDT_RESOURCE_L3];
+	struct rdt_resource *r_ldata = &rdt_resources_all[data_type];
+	struct rdt_resource *r_lcode = &rdt_resources_all[code_type];
+	struct rdt_resource *r_l = &rdt_resources_all[level];
 	int ret;
 
-	if (!r_l3->alloc_capable || !r_l3data->alloc_capable ||
-	    !r_l3code->alloc_capable)
+	if (!r_l->alloc_capable || !r_ldata->alloc_capable ||
+	    !r_lcode->alloc_capable)
 		return -EINVAL;
 
-	ret = set_l3_qos_cfg(r_l3, true);
+	ret = set_cache_qos_cfg(level, true);
 	if (!ret) {
-		r_l3->alloc_enabled = false;
-		r_l3data->alloc_enabled = true;
-		r_l3code->alloc_enabled = true;
+		r_l->alloc_enabled = false;
+		r_ldata->alloc_enabled = true;
+		r_lcode->alloc_enabled = true;
 	}
 	return ret;
 }
 
-static void cdp_disable(void)
+static int cdpl3_enable(void)
 {
-	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3];
+	return cdp_enable(RDT_RESOURCE_L3, RDT_RESOURCE_L3DATA,
+			  RDT_RESOURCE_L3CODE);
+}
+
+static int cdpl2_enable(void)
+{
+	return cdp_enable(RDT_RESOURCE_L2, RDT_RESOURCE_L2DATA,
+			  RDT_RESOURCE_L2CODE);
+}
+
+static void cdp_disable(int level, int data_type, int code_type)
+{
+	struct rdt_resource *r = &rdt_resources_all[level];
 
 	r->alloc_enabled = r->alloc_capable;
 
-	if (rdt_resources_all[RDT_RESOURCE_L3DATA].alloc_enabled) {
-		rdt_resources_all[RDT_RESOURCE_L3DATA].alloc_enabled = false;
-		rdt_resources_all[RDT_RESOURCE_L3CODE].alloc_enabled = false;
-		set_l3_qos_cfg(r, false);
+	if (rdt_resources_all[data_type].alloc_enabled) {
+		rdt_resources_all[data_type].alloc_enabled = false;
+		rdt_resources_all[code_type].alloc_enabled = false;
+		set_cache_qos_cfg(level, false);
 	}
 }
 
+static void cdpl3_disable(void)
+{
+	cdp_disable(RDT_RESOURCE_L3, RDT_RESOURCE_L3DATA, RDT_RESOURCE_L3CODE);
+}
+
+static void cdpl2_disable(void)
+{
+	cdp_disable(RDT_RESOURCE_L2, RDT_RESOURCE_L2DATA, RDT_RESOURCE_L2CODE);
+}
+
+static void cdp_disable_all(void)
+{
+	if (rdt_resources_all[RDT_RESOURCE_L3DATA].alloc_enabled)
+		cdpl3_disable();
+	if (rdt_resources_all[RDT_RESOURCE_L2DATA].alloc_enabled)
+		cdpl2_disable();
+}
+
 static int parse_rdtgroupfs_options(char *data)
 {
 	char *token, *o = data;
 	int ret = 0;
 
 	while ((token = strsep(&o, ",")) != NULL) {
-		if (!*token)
-			return -EINVAL;
+		if (!*token) {
+			ret = -EINVAL;
+			goto out;
+		}
 
-		if (!strcmp(token, "cdp"))
-			ret = cdp_enable();
+		if (!strcmp(token, "cdp")) {
+			ret = cdpl3_enable();
+			if (ret)
+				goto out;
+		} else if (!strcmp(token, "cdpl2")) {
+			ret = cdpl2_enable();
+			if (ret)
+				goto out;
+		} else {
+			ret = -EINVAL;
+			goto out;
+		}
 	}
 
+	return 0;
+
+out:
+	pr_err("Invalid mount option \"%s\"\n", token);
+
 	return ret;
 }
 
@@ -1061,8 +1116,7 @@ void rdtgroup_kn_unlock(struct kernfs_node *kn)
 	if (atomic_dec_and_test(&rdtgrp->waitcount) &&
 	    (rdtgrp->flags & RDT_DELETED)) {
 		kernfs_unbreak_active_protection(kn);
-		kernfs_put(rdtgrp->kn);
-		kfree(rdtgrp);
+		rdtgroup_remove(rdtgrp);
 	} else {
 		kernfs_unbreak_active_protection(kn);
 	}
@@ -1113,7 +1167,6 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
 			dentry = ERR_PTR(ret);
 			goto out_info;
 		}
-		kernfs_get(kn_mongrp);
 
 		ret = mkdir_mondata_all(rdtgroup_default.kn,
 					&rdtgroup_default, &kn_mondata);
@@ -1121,7 +1174,6 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
 			dentry = ERR_PTR(ret);
 			goto out_mongrp;
 		}
-		kernfs_get(kn_mondata);
 		rdtgroup_default.mon.mon_data_kn = kn_mondata;
 	}
 
@@ -1155,7 +1207,7 @@ out_mongrp:
 out_info:
 	kernfs_remove(kn_info);
 out_cdp:
-	cdp_disable();
+	cdp_disable_all();
 out:
 	mutex_unlock(&rdtgroup_mutex);
 	cpus_read_unlock();
@@ -1264,7 +1316,7 @@ static void free_all_child_rdtgrp(struct rdtgroup *rdtgrp)
 		if (atomic_read(&sentry->waitcount) != 0)
 			sentry->flags = RDT_DELETED;
 		else
-			kfree(sentry);
+			rdtgroup_remove(sentry);
 	}
 }
 
@@ -1302,7 +1354,7 @@ static void rmdir_all_sub(void)
 		if (atomic_read(&rdtgrp->waitcount) != 0)
 			rdtgrp->flags = RDT_DELETED;
 		else
-			kfree(rdtgrp);
+			rdtgroup_remove(rdtgrp);
 	}
 	/* Notify online CPUs to update per cpu storage and PQR_ASSOC MSR */
 	update_closid_rmid(cpu_online_mask, &rdtgroup_default);
@@ -1322,7 +1374,7 @@ static void rdt_kill_sb(struct super_block *sb)
 	/*Put everything back to default values. */
 	for_each_alloc_enabled_rdt_resource(r)
 		reset_all_ctrls(r);
-	cdp_disable();
+	cdp_disable_all();
 	rmdir_all_sub();
 	static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
 	static_branch_disable_cpuslocked(&rdt_mon_enable_key);
@@ -1396,11 +1448,6 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
 	if (IS_ERR(kn))
 		return PTR_ERR(kn);
 
-	/*
-	 * This extra ref will be put in kernfs_remove() and guarantees
-	 * that kn is always accessible.
-	 */
-	kernfs_get(kn);
 	ret = rdtgroup_kn_set_ugid(kn);
 	if (ret)
 		goto out_destroy;
@@ -1561,8 +1608,8 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
 	/*
 	 * kernfs_remove() will drop the reference count on "kn" which
 	 * will free it. But we still need it to stick around for the
-	 * rdtgroup_kn_unlock(kn} call below. Take one extra reference
-	 * here, which will be dropped inside rdtgroup_kn_unlock().
+	 * rdtgroup_kn_unlock(kn) call. Take one extra reference here,
+	 * which will be dropped by kernfs_put() in rdtgroup_remove().
 	 */
 	kernfs_get(kn);
 
@@ -1596,6 +1643,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
 out_idfree:
 	free_rmid(rdtgrp->mon.rmid);
 out_destroy:
+	kernfs_put(rdtgrp->kn);
 	kernfs_remove(rdtgrp->kn);
 out_free_rgrp:
 	kfree(rdtgrp);
@@ -1608,7 +1656,7 @@ static void mkdir_rdt_prepare_clean(struct rdtgroup *rgrp)
 {
 	kernfs_remove(rgrp->kn);
 	free_rmid(rgrp->mon.rmid);
-	kfree(rgrp);
+	rdtgroup_remove(rgrp);
 }
 
 /*
@@ -1692,6 +1740,19 @@ out_unlock:
 	return ret;
 }
 
+/* Restore the qos cfg state when a domain comes online */
+void rdt_domain_reconfigure_cdp(struct rdt_resource *r)
+{
+	if (!r->alloc_capable)
+		return;
+
+	if (r == &rdt_resources_all[RDT_RESOURCE_L2DATA])
+		l2_qos_cfg_update(&r->alloc_enabled);
+
+	if (r == &rdt_resources_all[RDT_RESOURCE_L3DATA])
+		l3_qos_cfg_update(&r->alloc_enabled);
+}
+
 /*
  * We allow creating mon groups only with in a directory called "mon_groups"
  * which is present in every ctrl_mon group. Check if this is a valid
@@ -1761,11 +1822,6 @@ static int rdtgroup_rmdir_mon(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
 	WARN_ON(list_empty(&prdtgrp->mon.crdtgrp_list));
 	list_del(&rdtgrp->mon.crdtgrp_list);
 
-	/*
-	 * one extra hold on this, will drop when we kfree(rdtgrp)
-	 * in rdtgroup_kn_unlock()
-	 */
-	kernfs_get(kn);
 	kernfs_remove(rdtgrp->kn);
 
 	return 0;
@@ -1802,11 +1858,6 @@ static int rdtgroup_rmdir_ctrl(struct kernfs_node *kn, struct rdtgroup *rdtgrp,
 
 	list_del(&rdtgrp->rdtgroup_list);
 
-	/*
-	 * one extra hold on this, will drop when we kfree(rdtgrp)
-	 * in rdtgroup_kn_unlock()
-	 */
-	kernfs_get(kn);
 	kernfs_remove(rdtgrp->kn);
 
 	/*
@@ -1840,7 +1891,8 @@ static int rdtgroup_rmdir(struct kernfs_node *kn)
 	 * If the rdtgroup is a mon group and parent directory
 	 * is a valid "mon_groups" directory, remove the mon group.
 	 */
-	if (rdtgrp->type == RDTCTRL_GROUP && parent_kn == rdtgroup_default.kn)
+	if (rdtgrp->type == RDTCTRL_GROUP && parent_kn == rdtgroup_default.kn &&
+	    rdtgrp != &rdtgroup_default)
 		ret = rdtgroup_rmdir_ctrl(kn, rdtgrp, tmpmask);
 	else if (rdtgrp->type == RDTMON_GROUP &&
 		 is_mon_groups(parent_kn, kn->name))