x86/resctrl: Remove fflags from struct rdt_resource

The resctrl arch code specifies whether a resource controls a cache or memory
using the fflags field. This field is then used by resctrl to determine which
files should be exposed in the filesystem.

Allowing the architecture to pick this value means the RFTYPE_ flags have to
be in a shared header, and allows an architecture to create a combination that
resctrl does not support.

Remove the fflags field, and pick the value based on the resource id.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20250311183715.16445-4-james.morse@arm.com

Author: James Morse

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

@@ -74,7 +74,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 			.mon_domains		= mon_domain_init(RDT_RESOURCE_L3),
 			.parse_ctrlval		= parse_cbm,
 			.format_str		= "%d=%0*x",
-			.fflags			= RFTYPE_RES_CACHE,
 		},
 		.msr_base		= MSR_IA32_L3_CBM_BASE,
 		.msr_update		= cat_wrmsr,
@@ -88,7 +87,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 			.ctrl_domains		= ctrl_domain_init(RDT_RESOURCE_L2),
 			.parse_ctrlval		= parse_cbm,
 			.format_str		= "%d=%0*x",
-			.fflags			= RFTYPE_RES_CACHE,
 		},
 		.msr_base		= MSR_IA32_L2_CBM_BASE,
 		.msr_update		= cat_wrmsr,
@@ -102,7 +100,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 			.ctrl_domains		= ctrl_domain_init(RDT_RESOURCE_MBA),
 			.parse_ctrlval		= parse_bw,
 			.format_str		= "%d=%*u",
-			.fflags			= RFTYPE_RES_MB,
 		},
 	},
 	[RDT_RESOURCE_SMBA] =
@@ -114,7 +111,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
 			.ctrl_domains		= ctrl_domain_init(RDT_RESOURCE_SMBA),
 			.parse_ctrlval		= parse_bw,
 			.format_str		= "%d=%*u",
-			.fflags			= RFTYPE_RES_MB,
 		},
 	},
 };

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

@@ -2165,6 +2165,20 @@ static int rdtgroup_mkdir_info_resdir(void *priv, char *name,
 	return ret;
 }
 
+static unsigned long fflags_from_resource(struct rdt_resource *r)
+{
+	switch (r->rid) {
+	case RDT_RESOURCE_L3:
+	case RDT_RESOURCE_L2:
+		return RFTYPE_RES_CACHE;
+	case RDT_RESOURCE_MBA:
+	case RDT_RESOURCE_SMBA:
+		return RFTYPE_RES_MB;
+	}
+
+	return WARN_ON_ONCE(1);
+}
+
 static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 {
 	struct resctrl_schema *s;
@@ -2185,14 +2199,14 @@ static int rdtgroup_create_info_dir(struct kernfs_node *parent_kn)
 	/* loop over enabled controls, these are all alloc_capable */
 	list_for_each_entry(s, &resctrl_schema_all, list) {
 		r = s->res;
-		fflags = r->fflags | RFTYPE_CTRL_INFO;
+		fflags = fflags_from_resource(r) | RFTYPE_CTRL_INFO;
 		ret = rdtgroup_mkdir_info_resdir(s, s->name, fflags);
 		if (ret)
 			goto out_destroy;
 	}
 
 	for_each_mon_capable_rdt_resource(r) {
-		fflags = r->fflags | RFTYPE_MON_INFO;
+		fflags = fflags_from_resource(r) | RFTYPE_MON_INFO;
 		sprintf(name, "%s_MON", r->name);
 		ret = rdtgroup_mkdir_info_resdir(r, name, fflags);
 		if (ret)

include/linux/resctrl.h

@@ -210,7 +210,6 @@ enum resctrl_scope {
  * @format_str:		Per resource format string to show domain value
  * @parse_ctrlval:	Per resource function pointer to parse control values
  * @evt_list:		List of monitoring events
- * @fflags:		flags to choose base and info files
  * @cdp_capable:	Is the CDP feature available on this resource
  */
 struct rdt_resource {
@@ -232,7 +231,6 @@ struct rdt_resource {
 						 struct resctrl_schema *s,
 						 struct rdt_ctrl_domain *d);
 	struct list_head	evt_list;
-	unsigned long		fflags;
 	bool			cdp_capable;
 };