x86/resctrl: Initialize a new resource group with default MBA values

Currently, when a new resource group is created, the allocation values
of the MBA resource are not initialized and remain meaningless data.

For example:

  mkdir /sys/fs/resctrl/p1
  cat /sys/fs/resctrl/p1/schemata
  MB:0=100;1=100

  echo "MB:0=10;1=20" > /sys/fs/resctrl/p1/schemata
  cat /sys/fs/resctrl/p1/schemata
  MB:0= 10;1= 20

  rmdir /sys/fs/resctrl/p1
  mkdir /sys/fs/resctrl/p2
  cat /sys/fs/resctrl/p2/schemata
  MB:0= 10;1= 20

Therefore, when the new group is created, it is reasonable to initialize
MBA resource with default values.

Initialize the MBA resource and cache resources in separate functions.

 [ bp: Add newlines between code blocks for better readability. ]
Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: pei.p.jia@intel.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/1555499329-1170-3-git-send-email-xiaochen.shen@intel.com

arch/x86/kernel/cpu/resctrl/ctrlmondata.c

@@ -342,10 +342,10 @@ int update_domains(struct rdt_resource *r, int closid)
 	if (cpumask_empty(cpu_mask) || mba_sc)
 		goto done;
 	cpu = get_cpu();
-	/* Update CBM on this cpu if it's in cpu_mask. */
+	/* Update resource control msr on this CPU if it's in cpu_mask. */
 	if (cpumask_test_cpu(cpu, cpu_mask))
 		rdt_ctrl_update(&msr_param);
-	/* Update CBM on other cpus. */
+	/* Update resource control msr on other CPUs. */
 	smp_call_function_many(cpu_mask, rdt_ctrl_update, &msr_param, 1);
 	put_cpu();
 

arch/x86/kernel/cpu/resctrl/rdtgroup.c

@@ -2581,8 +2581,8 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
 	return 0;
 }
 
-/**
- * rdtgroup_init_alloc - Initialize the new RDT group's allocations
+/*
+ * Initialize cache resources with default values.
  *
  * A new RDT group is being created on an allocation capable (CAT)
  * supporting system. Set this group up to start off with all usable
@@ -2591,38 +2591,52 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
  * If there are no more shareable bits available on any domain then
  * the entire allocation will fail.
  */
-static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
+static int rdtgroup_init_cat(struct rdt_resource *r, u32 closid)
 {
-	struct rdt_resource *r;
 	struct rdt_domain *d;
 	int ret;
 
-	for_each_alloc_enabled_rdt_resource(r) {
-		/*
-		 * Only initialize default allocations for CBM cache
-		 * resources
-		 */
-		if (r->rid == RDT_RESOURCE_MBA)
-			continue;
 	list_for_each_entry(d, &r->domains, list) {
-			ret = __init_one_rdt_domain(d, r, rdtgrp->closid);
+		ret = __init_one_rdt_domain(d, r, closid);
 		if (ret < 0)
 			return ret;
 	}
+
+	return 0;
+}
+
+/* Initialize MBA resource with default values. */
+static void rdtgroup_init_mba(struct rdt_resource *r)
+{
+	struct rdt_domain *d;
+
+	list_for_each_entry(d, &r->domains, list) {
+		d->new_ctrl = is_mba_sc(r) ? MBA_MAX_MBPS : r->default_ctrl;
+		d->have_new_ctrl = true;
 	}
+}
+
+/* Initialize the RDT group's allocations. */
+static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
+{
+	struct rdt_resource *r;
+	int ret;
 
 	for_each_alloc_enabled_rdt_resource(r) {
-		/*
-		 * Only initialize default allocations for CBM cache
-		 * resources
-		 */
-		if (r->rid == RDT_RESOURCE_MBA)
-			continue;
+		if (r->rid == RDT_RESOURCE_MBA) {
+			rdtgroup_init_mba(r);
+		} else {
+			ret = rdtgroup_init_cat(r, rdtgrp->closid);
+			if (ret < 0)
+				return ret;
+		}
+
 		ret = update_domains(r, rdtgrp->closid);
 		if (ret < 0) {
 			rdt_last_cmd_puts("Failed to initialize allocations\n");
 			return ret;
 		}
+
 	}
 
 	rdtgrp->mode = RDT_MODE_SHAREABLE;