Merge tag 'x86_cache_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 cache resource control updates from Borislav Petkov:

 - add logic to correct MBM total and local values fixing errata SKX99
   and BDF102 (Fenghua Yu)

 - cleanups

* tag 'x86_cache_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/resctrl: Clean up unused function parameter in rmdir path
  x86/resctrl: Constify kernfs_ops
  x86/resctrl: Correct MBM total and local values
  Documentation/x86: Rename resctrl_ui.rst and add two errata to the file

1 files changed, 80 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index a98519a3a2e6..7ac31210e452 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -64,6 +64,69 @@ unsigned int rdt_mon_features;
  */
 unsigned int resctrl_cqm_threshold;
 
+#define CF(cf)	((unsigned long)(1048576 * (cf) + 0.5))
+
+/*
+ * The correction factor table is documented in Documentation/x86/resctrl.rst.
+ * If rmid > rmid threshold, MBM total and local values should be multiplied
+ * by the correction factor.
+ *
+ * The original table is modified for better code:
+ *
+ * 1. The threshold 0 is changed to rmid count - 1 so don't do correction
+ *    for the case.
+ * 2. MBM total and local correction table indexed by core counter which is
+ *    equal to (x86_cache_max_rmid + 1) / 8 - 1 and is from 0 up to 27.
+ * 3. The correction factor is normalized to 2^20 (1048576) so it's faster
+ *    to calculate corrected value by shifting:
+ *    corrected_value = (original_value * correction_factor) >> 20
+ */
+static const struct mbm_correction_factor_table {
+	u32 rmidthreshold;
+	u64 cf;
+} mbm_cf_table[] __initdata = {
+	{7,	CF(1.000000)},
+	{15,	CF(1.000000)},
+	{15,	CF(0.969650)},
+	{31,	CF(1.000000)},
+	{31,	CF(1.066667)},
+	{31,	CF(0.969650)},
+	{47,	CF(1.142857)},
+	{63,	CF(1.000000)},
+	{63,	CF(1.185115)},
+	{63,	CF(1.066553)},
+	{79,	CF(1.454545)},
+	{95,	CF(1.000000)},
+	{95,	CF(1.230769)},
+	{95,	CF(1.142857)},
+	{95,	CF(1.066667)},
+	{127,	CF(1.000000)},
+	{127,	CF(1.254863)},
+	{127,	CF(1.185255)},
+	{151,	CF(1.000000)},
+	{127,	CF(1.066667)},
+	{167,	CF(1.000000)},
+	{159,	CF(1.454334)},
+	{183,	CF(1.000000)},
+	{127,	CF(0.969744)},
+	{191,	CF(1.280246)},
+	{191,	CF(1.230921)},
+	{215,	CF(1.000000)},
+	{191,	CF(1.143118)},
+};
+
+static u32 mbm_cf_rmidthreshold __read_mostly = UINT_MAX;
+static u64 mbm_cf __read_mostly;
+
+static inline u64 get_corrected_mbm_count(u32 rmid, unsigned long val)
+{
+	/* Correct MBM value. */
+	if (rmid > mbm_cf_rmidthreshold)
+		val = (val * mbm_cf) >> 20;
+
+	return val;
+}
+
 static inline struct rmid_entry *__rmid_entry(u32 rmid)
 {
 	struct rmid_entry *entry;
@@ -260,7 +323,8 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)
 	m->chunks += chunks;
 	m->prev_msr = tval;
 
-	rr->val += m->chunks;
+	rr->val += get_corrected_mbm_count(rmid, m->chunks);
+
 	return 0;
 }
 
@@ -279,7 +343,7 @@ static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
 		return;
 
 	chunks = mbm_overflow_count(m->prev_bw_msr, tval, rr->r->mbm_width);
-	cur_bw = (chunks * r->mon_scale) >> 20;
+	cur_bw = (get_corrected_mbm_count(rmid, chunks) * r->mon_scale) >> 20;
 
 	if (m->delta_comp)
 		m->delta_bw = abs(cur_bw - m->prev_bw);
@@ -642,3 +706,17 @@ int rdt_get_mon_l3_config(struct rdt_resource *r)
 
 	return 0;
 }
+
+void __init intel_rdt_mbm_apply_quirk(void)
+{
+	int cf_index;
+
+	cf_index = (boot_cpu_data.x86_cache_max_rmid + 1) / 8 - 1;
+	if (cf_index >= ARRAY_SIZE(mbm_cf_table)) {
+		pr_info("No MBM correction factor available\n");
+		return;
+	}
+
+	mbm_cf_rmidthreshold = mbm_cf_table[cf_index].rmidthreshold;
+	mbm_cf = mbm_cf_table[cf_index].cf;
+}