[PATCH 16/24] x86/resctrl: Add a helper to read/set the CDP configuration

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

Currently whether CDP is enabled is described in the alloc_enabled
and alloc_capable flags, which are set differently between the L3
and L3CODE+L3DATA resources.

To merge these resources, to give us one configuration, the CDP state
of the resource needs tracking explicitly. Add cdp_capable as something
visible to resctrl, and cdp_enabled as something the arch code manages.

resctrl_arch_set_cdp_enabled() lets resctrl enable or disable CDP
on a resource. resctrl_arch_get_cdp_enabled() lets it read the
current state.

With Arm's MPAM, separate code and data closids is a part of the
CPU configuration. Enabling CDP for one resource means all resources
see the different closid values.

Signed-off-by: James Morse <james.morse@arm.com>

---
It may be possible for MPAM to apply the same 'L3' configuration to
the two closid that are in use, giving the illusion that CDP is enabled
for some resources, but disabled for others ... but this will complicate
monitoring.
---
 arch/x86/kernel/cpu/resctrl/core.c        |  4 ++
 arch/x86/kernel/cpu/resctrl/internal.h    | 11 +++-
 arch/x86/kernel/cpu/resctrl/pseudo_lock.c |  4 +-
 arch/x86/kernel/cpu/resctrl/rdtgroup.c    | 67 +++++++++++++----------
 4 files changed, 55 insertions(+), 31 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index cda071009fed..7e98869ba006 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -369,11 +369,15 @@ static void rdt_get_cdp_config(int level, int type)
 	r->cache.shareable_bits = r_l->cache.shareable_bits;
 	r->data_width = (r->cache.cbm_len + 3) / 4;
 	r->alloc_capable = true;
+	hw_res_l->cdp_capable = true;
+	hw_res->cdp_capable = true;
 	/*
 	 * By default, CDP is disabled. CDP can be enabled by mount parameter
 	 * "cdp" during resctrl file system mount time.
 	 */
 	r->alloc_enabled = false;
+	hw_res_l->cdp_enabled = false;
+	hw_res->cdp_enabled = false;
 }
 
 static void rdt_get_cdp_l3_config(void)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index e86550d888cc..f039fd9f4f4f 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -365,6 +365,8 @@ struct rdt_parse_data {
  * @msr_base:		Base MSR address for CBMs
  * @msr_update:		Function pointer to update QOS MSRs
  * @mon_scale:		cqm counter * mon_scale = occupancy in bytes
+ * @cdp_capable:	Is the CDP feature available on this resource
+ * @cdp_enabled:	CDP state of this resource
  */
 struct rdt_hw_resource {
 	enum resctrl_conf_type	conf_type;
@@ -377,6 +379,8 @@ struct rdt_hw_resource {
 				 struct rdt_resource *r);
 	unsigned int		mon_scale;
 	unsigned int		mbm_width;
+	bool			cdp_capable;
+	bool			cdp_enabled;
 };
 
 static inline struct rdt_hw_resource *resctrl_to_arch_res(struct rdt_resource *r)
@@ -397,7 +401,7 @@ DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
 
 extern struct dentry *debugfs_resctrl;
 
-enum {
+enum resctrl_res_level {
 	RDT_RESOURCE_L3,
 	RDT_RESOURCE_L3DATA,
 	RDT_RESOURCE_L3CODE,
@@ -418,6 +422,11 @@ static inline struct rdt_resource *resctrl_inc(struct rdt_resource *res)
 	return &hw_res->resctrl;
 }
 
+static inline bool resctrl_arch_get_cdp_enabled(enum resctrl_res_level l)
+{
+	return rdt_resources_all[l].cdp_enabled;
+}
+
 #define for_each_rdt_resource(r)					      \
 	for (r = &rdt_resources_all[0].resctrl;				      \
 	     r < &rdt_resources_all[RDT_NUM_RESOURCES].resctrl;		      \
diff --git a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
index d9d9861f244f..f126d442a65f 100644
--- a/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
+++ b/arch/x86/kernel/cpu/resctrl/pseudo_lock.c
@@ -684,8 +684,8 @@ int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp)
 	 *   resource, the portion of cache used by it should be made
 	 *   unavailable to all future allocations from both resources.
 	 */
-	if (rdt_resources_all[RDT_RESOURCE_L3DATA].resctrl.alloc_enabled ||
-	    rdt_resources_all[RDT_RESOURCE_L2DATA].resctrl.alloc_enabled) {
+	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3) ||
+	    resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2)) {
 		rdt_last_cmd_puts("CDP enabled\n");
 		return -EINVAL;
 	}
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index f168f5a39242..6e150560c3c1 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1995,51 +1995,62 @@ static int cdp_enable(int level, int data_type, int code_type)
 		r_l->alloc_enabled = false;
 		r_ldata->alloc_enabled = true;
 		r_lcode->alloc_enabled = true;
+		rdt_resources_all[level].cdp_enabled = true;
+		rdt_resources_all[data_type].cdp_enabled = true;
+		rdt_resources_all[code_type].cdp_enabled = true;
 	}
 	return ret;
 }
 
-static int cdpl3_enable(void)
-{
-	return cdp_enable(RDT_RESOURCE_L3, RDT_RESOURCE_L3DATA,
-			  RDT_RESOURCE_L3CODE);
-}
-
-static int cdpl2_enable(void)
-{
-	return cdp_enable(RDT_RESOURCE_L2, RDT_RESOURCE_L2DATA,
-			  RDT_RESOURCE_L2CODE);
-}
-
 static void cdp_disable(int level, int data_type, int code_type)
 {
-	struct rdt_resource *r = &rdt_resources_all[level].resctrl;
+	struct rdt_hw_resource *r_hw = &rdt_resources_all[level];
+	struct rdt_resource *r = &r_hw->resctrl;
 
 	r->alloc_enabled = r->alloc_capable;
 
-	if (rdt_resources_all[data_type].resctrl.alloc_enabled) {
+	if (r_hw->cdp_enabled) {
 		rdt_resources_all[data_type].resctrl.alloc_enabled = false;
 		rdt_resources_all[code_type].resctrl.alloc_enabled = false;
 		set_cache_qos_cfg(level, false);
+		r_hw->cdp_enabled = false;
+		rdt_resources_all[data_type].cdp_enabled = false;
+		rdt_resources_all[code_type].cdp_enabled = false;
 	}
 }
 
-static void cdpl3_disable(void)
+int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable)
 {
-	cdp_disable(RDT_RESOURCE_L3, RDT_RESOURCE_L3DATA, RDT_RESOURCE_L3CODE);
-}
+	struct rdt_hw_resource *hw_res = &rdt_resources_all[l];
+	enum resctrl_res_level code_type, data_type;
 
-static void cdpl2_disable(void)
-{
-	cdp_disable(RDT_RESOURCE_L2, RDT_RESOURCE_L2DATA, RDT_RESOURCE_L2CODE);
+	if (!hw_res->cdp_capable)
+		return -EINVAL;
+
+	if (l == RDT_RESOURCE_L3) {
+		code_type = RDT_RESOURCE_L3CODE;
+		data_type = RDT_RESOURCE_L3DATA;
+	} else if (l == RDT_RESOURCE_L2) {
+		code_type = RDT_RESOURCE_L2CODE;
+		data_type = RDT_RESOURCE_L2DATA;
+	} else {
+		return -EINVAL;
+	}
+
+	if (enable)
+		return cdp_enable(l, data_type, code_type);
+
+	cdp_disable(l, data_type, code_type);
+
+	return 0;
 }
 
 static void cdp_disable_all(void)
 {
-	if (rdt_resources_all[RDT_RESOURCE_L3DATA].resctrl.alloc_enabled)
-		cdpl3_disable();
-	if (rdt_resources_all[RDT_RESOURCE_L2DATA].resctrl.alloc_enabled)
-		cdpl2_disable();
+	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
+		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
+	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
+		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
 }
 
 /*
@@ -2118,10 +2129,10 @@ static int rdt_enable_ctx(struct rdt_fs_context *ctx)
 	int ret = 0;
 
 	if (ctx->enable_cdpl2)
-		ret = cdpl2_enable();
+		ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, true);
 
 	if (!ret && ctx->enable_cdpl3)
-		ret = cdpl3_enable();
+		ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, true);
 
 	if (!ret && ctx->enable_mba_mbps)
 		ret = set_mba_sc(true);
@@ -3243,10 +3254,10 @@ static int rdtgroup_rmdir(struct kernfs_node *kn)
 
 static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root *kf)
 {
-	if (rdt_resources_all[RDT_RESOURCE_L3DATA].resctrl.alloc_enabled)
+	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
 		seq_puts(seq, ",cdp");
 
-	if (rdt_resources_all[RDT_RESOURCE_L2DATA].resctrl.alloc_enabled)
+	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
 		seq_puts(seq, ",cdpl2");
 
 	if (is_mba_sc(&rdt_resources_all[RDT_RESOURCE_MBA].resctrl))
-- 
2.28.0