arm64/mpam: use 5% as min memory bandwidth

hulk inclusion
category: feature
bugzilla: 5510
CVE: NA
Signed-off-by: NXie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

arch/arm64/include/asm/mpam.h

@@ -336,6 +336,7 @@ struct raw_resctrl_resource {
 };
 
 int parse_cbm(char *buf, struct raw_resctrl_resource *r, struct rdt_domain *d);
+int parse_bw(char *buf, struct raw_resctrl_resource *r, struct rdt_domain *d);
 
 union mon_data_bits {
 	void *priv;

arch/arm64/kernel/mpam.c

@@ -207,8 +207,8 @@ struct raw_resctrl_resource raw_resctrl_resources_all[] = {
 	[MPAM_RESOURCE_MC] = {
 		.msr_update		= bw_wrmsr,
 		.msr_read		= bw_rdmsr,
-		.parse_ctrlval		= parse_cbm,	/* [FIXME] add parse_bw() helper */
-		.format_str		= "%d=%0*x",
+		.parse_ctrlval		= parse_bw,	/* [FIXME] add parse_bw() helper */
+		.format_str		= "%d=%0*d",
 		.mon_read		= mbwu_read,
 		.mon_write		= mbwu_write,
 	},
@@ -270,7 +270,8 @@ u64 bw_rdmsr(struct rdt_domain *d, int partid)
 	mpam_writel(partid, d->base + MPAMCFG_PART_SEL);
 	max = mpam_readl(d->base + MPAMCFG_MBW_MAX);
 
-	return MBW_MAX_GET(max);
+	max = MBW_MAX_GET(max);
+	return roundup((max * 100) / 64, 5);
 }
 
 /*

arch/arm64/kernel/mpam_ctrlmon.c

@@ -82,6 +82,68 @@ int parse_cbm(char *buf, struct raw_resctrl_resource *r, struct rdt_domain *d)
 	return 0;
 }
 
+/* define bw_min as 5 percentage, that are 5% ~ 100% which cresponding masks: */
+static u32 bw_max_mask[20] = {
+	 3,	/*  3/64:  5% */
+	 6,	/*  6/64: 10% */
+	10,	/* 10/64: 15% */
+	13,	/* 13/64: 20% */
+	16,	/* 16/64: 25% */
+	19,	/* ... */
+	22,
+	26,
+	29,
+	32,
+	35,
+	38,
+	42,
+	45,
+	48,
+	51,
+	54,
+	58,
+	61,
+	63	/* 100% */
+};
+
+static bool bw_validate(char *buf, unsigned long *data, struct raw_resctrl_resource *r)
+{
+	unsigned long bw;
+	int ret, idx;
+
+	ret = kstrtoul(buf, 10, &bw);
+	if (ret) {
+		rdt_last_cmd_printf("non-hex character in mask %s\n", buf);
+		return false;
+	}
+
+	bw = bw < 5 ? 5 : bw;
+	bw = bw > 100 ? 100 : bw;
+
+	idx = roundup(bw, 5) / 5 - 1;
+
+	*data = bw_max_mask[idx];
+	return true;
+}
+
+int parse_bw(char *buf, struct raw_resctrl_resource *r, struct rdt_domain *d)
+{
+	unsigned long data;
+
+	if (d->have_new_ctrl) {
+		rdt_last_cmd_printf("duplicate domain %d\n", d->id);
+		return -EINVAL;
+	}
+
+	if (!bw_validate(buf, &data, r))
+		return -EINVAL;
+
+	d->new_ctrl = data;
+	d->have_new_ctrl = true;
+
+	return 0;
+}
+
 /*
  * For each domain in this resource we expect to find a series of:
  * id=mask