[PATCH 5/6] x86/intel_rdt: Enable L2 CDP in MSR IA32_L2_QOS_CFG

[Fenghua Yu]

From: Fenghua Yu <fenghua.yu@xxxxxxxxx>

Bit 0 in MSR IA32_L2_QOS_CFG (0xc82) is L2 CDP enable bit. By default,
the bit is zero, i.e. L2 CAT is enabled, and L2 CDP is disabled. When
the resctrl mount parameter "cdpl2" is given, the bit is set as 1 and L2
CDP is enabled.

In L2 CDP mode, the L2 CAT mask MSRs are re-mapped into interleaved pair
of mask MSRs for code (in odd number of CLOSID) and data (in even number
of CLOSID).

Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
---
 arch/x86/kernel/cpu/intel_rdt.h          |   3 +
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 117 ++++++++++++++++++++++++-------
 2 files changed, 94 insertions(+), 26 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index cea9f4b..1c5d2a3 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -6,12 +6,15 @@
 #include <linux/jump_label.h>
 
 #define IA32_L3_QOS_CFG		0xc81
+#define IA32_L2_QOS_CFG		0xc82
 #define IA32_L3_CBM_BASE	0xc90
 #define IA32_L2_CBM_BASE	0xd10
 #define IA32_MBA_THRTL_BASE	0xd50
 
 #define L3_QOS_CDP_ENABLE	0x01ULL
 
+#define L2_QOS_CDP_ENABLE	0x01ULL
+
 /*
  * Event IDs are used to program IA32_QM_EVTSEL before reading event
  * counter from IA32_QM_CTR
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 64c5ff9..bdab7d2 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -990,6 +990,7 @@ static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 	kernfs_remove(kn);
 	return ret;
 }
+
 static void l3_qos_cfg_update(void *arg)
 {
 	bool *enable = arg;
@@ -997,8 +998,17 @@ 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;
@@ -1006,16 +1016,24 @@ 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);
@@ -1023,52 +1041,99 @@ 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;
 }
 
@@ -1223,7 +1288,7 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
 out_info:
 	kernfs_remove(kn_info);
 out_cdp:
-	cdp_disable();
+	cdp_disable_all();
 out:
 	rdt_last_cmd_clear();
 	mutex_unlock(&rdtgroup_mutex);
@@ -1383,7 +1448,7 @@ 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);
-- 
1.8.3.1