[PATCH v4 20/24] x86/resctrl: Calculate the index from the configuration type

[James Morse]

resctrl uses cbm_idx() to map a closid to an index in the
configuration array. This is based on a multiplier and offset
that are held in the resource.

To merge the resources, the resctrl arch code needs to calculate
the index from something else, as there will only be one resource.

Decide based on the staged configuration type. This makes the
static mult and offset parameters redundant.

Reviewed-by: Jamie Iles <jamie@xxxxxxxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
---
No changes since v3.

Changes since v2:
 * Shuffled commit message,
---
 arch/x86/kernel/cpu/resctrl/core.c        | 12 -----------
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 25 ++++++++++++++---------
 include/linux/resctrl.h                   |  6 ------
 3 files changed, 15 insertions(+), 28 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 15b57f70564b..08603487cb7d 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -69,8 +69,6 @@ struct rdt_hw_resource rdt_resources_all[] = {
 			.cache_level		= 3,
 			.cache = {
 				.min_cbm_bits	= 1,
-				.cbm_idx_mult	= 1,
-				.cbm_idx_offset	= 0,
 			},
 			.domains		= domain_init(RDT_RESOURCE_L3),
 			.parse_ctrlval		= parse_cbm,
@@ -89,8 +87,6 @@ struct rdt_hw_resource rdt_resources_all[] = {
 			.cache_level		= 3,
 			.cache = {
 				.min_cbm_bits	= 1,
-				.cbm_idx_mult	= 2,
-				.cbm_idx_offset	= 0,
 			},
 			.domains		= domain_init(RDT_RESOURCE_L3DATA),
 			.parse_ctrlval		= parse_cbm,
@@ -109,8 +105,6 @@ struct rdt_hw_resource rdt_resources_all[] = {
 			.cache_level		= 3,
 			.cache = {
 				.min_cbm_bits	= 1,
-				.cbm_idx_mult	= 2,
-				.cbm_idx_offset	= 1,
 			},
 			.domains		= domain_init(RDT_RESOURCE_L3CODE),
 			.parse_ctrlval		= parse_cbm,
@@ -129,8 +123,6 @@ struct rdt_hw_resource rdt_resources_all[] = {
 			.cache_level		= 2,
 			.cache = {
 				.min_cbm_bits	= 1,
-				.cbm_idx_mult	= 1,
-				.cbm_idx_offset	= 0,
 			},
 			.domains		= domain_init(RDT_RESOURCE_L2),
 			.parse_ctrlval		= parse_cbm,
@@ -149,8 +141,6 @@ struct rdt_hw_resource rdt_resources_all[] = {
 			.cache_level		= 2,
 			.cache = {
 				.min_cbm_bits	= 1,
-				.cbm_idx_mult	= 2,
-				.cbm_idx_offset	= 0,
 			},
 			.domains		= domain_init(RDT_RESOURCE_L2DATA),
 			.parse_ctrlval		= parse_cbm,
@@ -169,8 +159,6 @@ struct rdt_hw_resource rdt_resources_all[] = {
 			.cache_level		= 2,
 			.cache = {
 				.min_cbm_bits	= 1,
-				.cbm_idx_mult	= 2,
-				.cbm_idx_offset	= 1,
 			},
 			.domains		= domain_init(RDT_RESOURCE_L2CODE),
 			.parse_ctrlval		= parse_cbm,
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index ebeab130f7eb..e384398374da 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -246,12 +246,17 @@ static int parse_line(char *line, struct resctrl_schema *s,
 	return -EINVAL;
 }
 
-static u32 cbm_idx(struct rdt_resource *r, unsigned int closid)
+static u32 get_config_index(u32 closid, enum resctrl_conf_type type)
 {
-	if (r->rid == RDT_RESOURCE_MBA)
+	switch (type) {
+	default:
+	case CDP_NONE:
 		return closid;
-
-	return closid * r->cache.cbm_idx_mult + r->cache.cbm_idx_offset;
+	case CDP_CODE:
+		return (closid * 2) + 1;
+	case CDP_DATA:
+		return (closid * 2);
+	}
 }
 
 static bool apply_config(struct rdt_hw_domain *hw_dom,
@@ -286,10 +291,6 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid)
 	if (!zalloc_cpumask_var(&cpu_mask, GFP_KERNEL))
 		return -ENOMEM;
 
-	msr_param.low = cbm_idx(r, closid);
-	msr_param.high = msr_param.low + 1;
-	msr_param.res = r;
-
 	mba_sc = is_mba_sc(r);
 	list_for_each_entry(d, &r->domains, list) {
 		hw_dom = resctrl_to_arch_dom(d);
@@ -298,9 +299,13 @@ int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid)
 			if (!cfg->have_new_ctrl)
 				continue;
 
-			idx = cbm_idx(r, closid);
+			idx = get_config_index(closid, t);
 			if (!apply_config(hw_dom, cfg, idx, cpu_mask, mba_sc))
 				continue;
+
+			msr_param.low = idx;
+			msr_param.high = msr_param.low + 1;
+			msr_param.res = r;
 		}
 	}
 
@@ -420,7 +425,7 @@ void resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d,
 			     u32 closid, enum resctrl_conf_type type, u32 *value)
 {
 	struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
-	u32 idx = cbm_idx(r, closid);
+	u32 idx = get_config_index(closid, type);
 
 	if (!is_mba_sc(r))
 		*value = hw_dom->ctrl_val[idx];
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 93bd8d3bbeb6..53ca55d5be1d 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -69,10 +69,6 @@ struct rdt_domain {
  * struct resctrl_cache - Cache allocation related data
  * @cbm_len:		Length of the cache bit mask
  * @min_cbm_bits:	Minimum number of consecutive bits to be set
- * @cbm_idx_mult:	Multiplier of CBM index
- * @cbm_idx_offset:	Offset of CBM index. CBM index is computed by:
- *			closid * cbm_idx_multi + cbm_idx_offset
- *			in a cache bit mask
  * @shareable_bits:	Bitmask of shareable resource with other
  *			executing entities
  * @arch_has_sparse_bitmaps:	True if a bitmap like f00f is valid.
@@ -83,8 +79,6 @@ struct rdt_domain {
 struct resctrl_cache {
 	unsigned int	cbm_len;
 	unsigned int	min_cbm_bits;
-	unsigned int	cbm_idx_mult;	// TODO remove this
-	unsigned int	cbm_idx_offset; // TODO remove this
 	unsigned int	shareable_bits;
 	bool		arch_has_sparse_bitmaps;
 	bool		arch_has_empty_bitmaps;
-- 
2.30.2