x86/intel_rdt/mba: Add schemata file support for MBA

Add support to update the MBA bandwidth values for the domains via the
schemata file.

 - Verify that the bandwidth value is valid

 - Round to the next control step depending on the bandwidth granularity of
   the hardware

 - Convert the bandwidth to delay values and write the delay values to
   the corresponding domain PQOS_MSRs.

[ tglx: Massaged changelog ]

Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1491611637-20417-9-git-send-email-vikas.shivappa@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/intel_rdt.h

@@ -181,6 +181,7 @@ struct rdt_resource {
 void rdt_get_cache_infofile(struct rdt_resource *r);
 void rdt_get_mba_infofile(struct rdt_resource *r);
 int parse_cbm(char *buf, struct rdt_resource *r, struct rdt_domain *d);
+int parse_bw(char *buf, struct rdt_resource *r,  struct rdt_domain *d);
 
 extern struct mutex rdtgroup_mutex;
 

arch/x86/kernel/cpu/intel_rdt.c

@@ -116,6 +116,8 @@ struct rdt_resource rdt_resources_all[] = {
 		.msr_base		= IA32_MBA_THRTL_BASE,
 		.msr_update		= mba_wrmsr,
 		.cache_level		= 3,
+		.parse_ctrlval		= parse_bw,
+		.format_str		= "%d=%*d",
 	},
 };
 

arch/x86/kernel/cpu/intel_rdt_schemata.c

@@ -28,6 +28,49 @@
 #include <linux/slab.h>
 #include <asm/intel_rdt.h>
 
+/*
+ * Check whether MBA bandwidth percentage value is correct. The value is
+ * checked against the minimum and max bandwidth values specified by the
+ * hardware. The allocated bandwidth percentage is rounded to the next
+ * control step available on the hardware.
+ */
+static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
+{
+	unsigned long bw;
+	int ret;
+
+	/*
+	 * Only linear delay values is supported for current Intel SKUs.
+	 */
+	if (!r->membw.delay_linear)
+		return false;
+
+	ret = kstrtoul(buf, 10, &bw);
+	if (ret)
+		return false;
+
+	if (bw < r->membw.min_bw || bw > r->default_ctrl)
+		return false;
+
+	*data = roundup(bw, (unsigned long)r->membw.bw_gran);
+	return true;
+}
+
+int parse_bw(char *buf, struct rdt_resource *r, struct rdt_domain *d)
+{
+	unsigned long data;
+
+	if (d->have_new_ctrl)
+		return -EINVAL;
+
+	if (!bw_validate(buf, &data, r))
+		return -EINVAL;
+	d->new_ctrl = data;
+	d->have_new_ctrl = true;
+
+	return 0;
+}
+
 /*
  * Check whether a cache bit mask is valid. The SDM says:
  *	Please note that all (and only) contiguous '1' combinations