x86/resctrl: Add a helper to read/set the CDP configuration

Whether CDP is enabled for a hardware resource like the L3 cache can be
found by inspecting the alloc_enabled flags of the L3CODE/L3DATA struct
rdt_hw_resources, even if they aren't in use.

Once these resources are merged, the flags can't be compared. Whether
CDP is enabled needs tracking explicitly. If another architecture is
emulating CDP the behaviour may not be per-resource. 'cdp_capable' needs
to be visible to resctrl, even if its not in use, as this affects the
padding of the schemata table visible to user-space.

Add cdp_enabled to struct rdt_hw_resource and cdp_capable to struct
rdt_resource. Add resctrl_arch_set_cdp_enabled() to let resctrl enable
or disable CDP on a resource. resctrl_arch_get_cdp_enabled() lets it
read the current state.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lkml.kernel.org/r/20210728170637.25610-12-james.morse@arm.com

1 files changed, 44 insertions, 31 deletions

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 305dcf8850a0..cc9dacd73438 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1940,14 +1940,16 @@ static int set_cache_qos_cfg(int level, bool enable)
 /* Restore the qos cfg state when a domain comes online */
 void rdt_domain_reconfigure_cdp(struct rdt_resource *r)
 {
-	if (!r->alloc_capable)
+	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
+
+	if (!r->cdp_capable)
 		return;
 
 	if (r == &rdt_resources_all[RDT_RESOURCE_L2DATA].r_resctrl)
-		l2_qos_cfg_update(&r->alloc_enabled);
+		l2_qos_cfg_update(&hw_res->cdp_enabled);
 
 	if (r == &rdt_resources_all[RDT_RESOURCE_L3DATA].r_resctrl)
-		l3_qos_cfg_update(&r->alloc_enabled);
+		l3_qos_cfg_update(&hw_res->cdp_enabled);
 }
 
 /*
@@ -1991,51 +1993,62 @@ 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].r_resctrl;
+	struct rdt_hw_resource *r_hw = &rdt_resources_all[level];
+	struct rdt_resource *r = &r_hw->r_resctrl;
 
 	r->alloc_enabled = r->alloc_capable;
 
-	if (rdt_resources_all[data_type].r_resctrl.alloc_enabled) {
+	if (r_hw->cdp_enabled) {
 		rdt_resources_all[data_type].r_resctrl.alloc_enabled = false;
 		rdt_resources_all[code_type].r_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->r_resctrl.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].r_resctrl.alloc_enabled)
-		cdpl3_disable();
-	if (rdt_resources_all[RDT_RESOURCE_L2DATA].r_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);
 }
 
 /*
@@ -2113,10 +2126,10 @@ 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);
@@ -3199,10 +3212,10 @@ out:
 
 static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root *kf)
 {
-	if (rdt_resources_all[RDT_RESOURCE_L3DATA].r_resctrl.alloc_enabled)
+	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
 		seq_puts(seq, ",cdp");
 
-	if (rdt_resources_all[RDT_RESOURCE_L2DATA].r_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].r_resctrl))