[PATCH v7 24/31] x86/resctrl: Add energy/perf choices to rdt boot option

[Tony Luck <tony.luck@intel.com>]

Legacy resctrl features are enumerated by X86_FEATURE_* flags. These
may be overridden by quirks to disable features in the case of errata.

Users can use kernel command line options to either disable a feature,
or to force enable a feature that was disabled by a quirk.

Provide similar functionality for hardware features that do not have an
X86_FEATURE_* flag.

Unlike other options that are tied to X86_FEATURE_* flags, these must be
queried by name. Add rdt_is_feature_enabled() to check whether quirks
or kernel command line have disabled a feature. Just like the legacy
feature options the command line enable overrides quirk disable.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 .../admin-guide/kernel-parameters.txt         |  2 +-
 arch/x86/kernel/cpu/resctrl/internal.h        |  2 ++
 arch/x86/kernel/cpu/resctrl/core.c            | 30 +++++++++++++++++++
 arch/x86/kernel/cpu/resctrl/intel_aet.c       |  7 +++++
 4 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f1f2c0874da9..4c12159f3ea0 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6066,7 +6066,7 @@
 	rdt=		[HW,X86,RDT]
 			Turn on/off individual RDT features. List is:
 			cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp,
-			mba, smba, bmec.
+			mba, smba, bmec, energy, perf.
 			E.g. to turn on cmt and turn off mba use:
 				rdt=cmt,!mba
 
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 0081fb5a4420..83166dd0b9c8 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -169,6 +169,8 @@ void __init intel_rdt_mbm_apply_quirk(void);
 
 void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
 
+bool rdt_is_feature_enabled(char *option);
+
 #ifdef CONFIG_X86_RESCTRL_CPU_INTEL_AET
 bool intel_aet_get_events(void);
 void __exit intel_aet_exit(void);
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index c954171073c7..83e046313600 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -791,6 +791,8 @@ enum {
 	RDT_FLAG_MBA,
 	RDT_FLAG_SMBA,
 	RDT_FLAG_BMEC,
+	RDT_FLAG_ENERGY,
+	RDT_FLAG_PERF,
 };
 
 #define RDT_OPT(idx, n, f)	\
@@ -816,6 +818,8 @@ static struct rdt_options rdt_options[]  __ro_after_init = {
 	RDT_OPT(RDT_FLAG_MBA,	    "mba",	X86_FEATURE_MBA),
 	RDT_OPT(RDT_FLAG_SMBA,	    "smba",	X86_FEATURE_SMBA),
 	RDT_OPT(RDT_FLAG_BMEC,	    "bmec",	X86_FEATURE_BMEC),
+	RDT_OPT(RDT_FLAG_ENERGY,    "energy",	0),
+	RDT_OPT(RDT_FLAG_PERF,	    "perf",	0),
 };
 #define NUM_RDT_OPTIONS ARRAY_SIZE(rdt_options)
 
@@ -865,6 +869,32 @@ bool rdt_cpu_has(int flag)
 	return ret;
 }
 
+/*
+ * Hardware features that do not have X86_FEATURE_* bits.
+ * There is no "hardware does not support this at all" case.
+ * Assume that the caller has already determined that
+ * support is present and just needs to check if the option has been
+ * disabled by a quirk that has not been overridden by a command
+ * line option.
+ */
+bool rdt_is_feature_enabled(char *name)
+{
+	struct rdt_options *o;
+	bool ret = true;
+
+	for (o = rdt_options; o < &rdt_options[NUM_RDT_OPTIONS]; o++) {
+		if (!strcmp(name, o->name)) {
+			if (o->force_off)
+				ret = false;
+			if (o->force_on)
+				ret = true;
+			break;
+		}
+	}
+
+	return ret;
+}
+
 bool resctrl_arch_is_evt_configurable(enum resctrl_event_id evt)
 {
 	if (!rdt_cpu_has(X86_FEATURE_BMEC))
diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/resctrl/intel_aet.c
index bd6011a95d12..e64a4630e95c 100644
--- a/arch/x86/kernel/cpu/resctrl/intel_aet.c
+++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c
@@ -49,6 +49,7 @@ struct pmt_event {
 
 /**
  * struct event_group - All information about a group of telemetry events.
+ * @name:		Name for this group (used by boot rdt= option)
  * @pfg:		Points to the aggregated telemetry space information
  *			within the OOBMSM driver that contains data for all
  *			telemetry regions.
@@ -61,6 +62,7 @@ struct pmt_event {
  */
 struct event_group {
 	/* Data fields for additional structures to manage this group. */
+	char				*name;
 	struct pmt_feature_group	*pfg;
 	struct list_head		list;
 	struct pkg_mmio_info		**pkginfo;
@@ -82,6 +84,7 @@ static LIST_HEAD(active_event_groups);
  * File: xml/CWF/OOBMSM/RMID-ENERGY/cwf_aggregator.xml
  */
 static struct event_group energy_0x26696143 = {
+	.name		= "energy",
 	.guid		= 0x26696143,
 	.mmio_size	= XML_MMIO_SIZE(576, 2, 3),
 	.num_events	= 2,
@@ -96,6 +99,7 @@ static struct event_group energy_0x26696143 = {
  * File: xml/CWF/OOBMSM/RMID-PERF/cwf_aggregator.xml
  */
 static struct event_group perf_0x26557651 = {
+	.name		= "perf",
 	.guid		= 0x26557651,
 	.mmio_size	= XML_MMIO_SIZE(576, 7, 3),
 	.num_events	= 7,
@@ -167,6 +171,9 @@ static int discover_events(struct event_group *e, struct pmt_feature_group *p)
 	struct pkg_mmio_info *mmi;
 	int num_pkgs;
 
+	if (!rdt_is_feature_enabled(e->name))
+		return -EINVAL;
+
 	num_pkgs = topology_max_packages();
 
 	/* Get per-package counts of telemetry regions for this event group */
-- 
2.50.0