[PATCH v4 07/39] x86/resctrl: Add max_bw to struct resctrl_membw

[James Morse <james.morse@arm.com>]

__rdt_get_mem_config_amd() and __get_mem_config_intel() both use
the default_ctrl property as a maximum value. This is because the
MBA schema works differently between these platforms. Doing this
complicates determining whether the default_ctrl property belongs
to the arch code, or can be derived from the schema format.

Add a max_bw property for AMD platforms to specify their maximum
MBA bandwidth. This isn't needed for other schema formats.

This will allow the default_ctrl to be generated from the schema
properties when it is needed.

Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
---
Changes since v2:
 * This patch is new.
---
 arch/x86/kernel/cpu/resctrl/core.c        | 2 ++
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 9 +++++----
 include/linux/resctrl.h                   | 2 ++
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index cb1d634274b4..f0bbc1350070 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -208,6 +208,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
 	hw_res->num_closid = edx.split.cos_max + 1;
 	max_delay = eax.split.max_delay + 1;
 	r->default_ctrl = MAX_MBA_BW;
+	r->membw.max_bw = MAX_MBA_BW;
 	r->membw.arch_needs_linear = true;
 	if (ecx & MBA_IS_LINEAR) {
 		r->membw.delay_linear = true;
@@ -245,6 +246,7 @@ static bool __rdt_get_mem_config_amd(struct rdt_resource *r)
 	hw_res->num_closid = edx + 1;
 	r->default_ctrl = 1 << eax;
 	r->schema_fmt = RESCTRL_SCHEMA_MBPS;
+	r->membw.max_bw = 1 << eax;
 
 	/* AMD does not use delay */
 	r->membw.delay_linear = false;
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 1d9ad4d82bf0..4de1fea6190d 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -57,10 +57,10 @@ static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
 		return false;
 	}
 
-	if ((bw < r->membw.min_bw || bw > r->default_ctrl) &&
+	if ((bw < r->membw.min_bw || bw > r->membw.max_bw) &&
 	    !is_mba_sc(r)) {
 		rdt_last_cmd_printf("MB value %ld out of range [%d,%d]\n", bw,
-				    r->membw.min_bw, r->default_ctrl);
+				    r->membw.min_bw, r->membw.max_bw);
 		return false;
 	}
 
@@ -108,8 +108,9 @@ static int parse_bw(struct rdt_parse_data *data, struct resctrl_schema *s,
  */
 static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
 {
-	unsigned long first_bit, zero_bit, val;
+	u32 supported_bits = BIT_MASK(r->cache.cbm_len + 1) - 1;
 	unsigned int cbm_len = r->cache.cbm_len;
+	unsigned long first_bit, zero_bit, val;
 	int ret;
 
 	ret = kstrtoul(buf, 16, &val);
@@ -118,7 +119,7 @@ static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
 		return false;
 	}
 
-	if ((r->cache.min_cbm_bits > 0 && val == 0) || val > r->default_ctrl) {
+	if ((r->cache.min_cbm_bits > 0 && val == 0) || val > supported_bits) {
 		rdt_last_cmd_puts("Mask out of range\n");
 		return false;
 	}
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index fe3c1ff732de..5f08fb2f235f 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -165,6 +165,7 @@ enum membw_throttle_mode {
 /**
  * struct resctrl_membw - Memory bandwidth allocation related data
  * @min_bw:		Minimum memory bandwidth percentage user can request
+ * @max_bw:		Maximum memory bandwidth value, used as the reset value
  * @bw_gran:		Granularity at which the memory bandwidth is allocated
  * @delay_linear:	True if memory B/W delay is in linear scale
  * @arch_needs_linear:	True if we can't configure non-linear resources
@@ -175,6 +176,7 @@ enum membw_throttle_mode {
  */
 struct resctrl_membw {
 	u32				min_bw;
+	u32				max_bw;
 	u32				bw_gran;
 	u32				delay_linear;
 	bool				arch_needs_linear;
-- 
2.39.2