[PATCH v4 26/31] x86/resctrl: Add energy/perf choices to rdt boot option

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

Users may want to force either of the telemetry features on
(in the case where they are disabled due to erratum) or off
(in the case that a limited number of RMIDs for a telemetry
feature reduces the number of monitor groups that can be
created.)

Unlike other options that are tied to X86_FEATURE_* flags,
these must be queried by name. Add a function to do that.

Add checks for users who forced either feature off.

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            | 19 +++++++++++++++++++
 arch/x86/kernel/cpu/resctrl/intel_aet.c       |  6 ++++++
 4 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d9fd26b95b34..4811bc812f0f 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5988,7 +5988,7 @@
 	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 dd5fe8a98304..92cbba9d82a8 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -167,6 +167,8 @@ void __init intel_rdt_mbm_apply_quirk(void);
 
 void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
 
+bool rdt_check_option(char *name, bool is_on, bool is_off);
+
 #ifdef CONFIG_INTEL_AET_RESCTRL
 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 9fa4cc66faf4..dc312e24ab87 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -795,6 +795,8 @@ enum {
 	RDT_FLAG_MBA,
 	RDT_FLAG_SMBA,
 	RDT_FLAG_BMEC,
+	RDT_FLAG_ENERGY,
+	RDT_FLAG_PERF,
 };
 
 #define RDT_OPT(idx, n, f)	\
@@ -820,6 +822,8 @@ 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)
 
@@ -869,6 +873,21 @@ bool rdt_cpu_has(int flag)
 	return ret;
 }
 
+/* Check if a named option has been forced on, or forced off */
+bool rdt_check_option(char *name, bool is_on, bool is_off)
+{
+	struct rdt_options *o;
+
+	WARN_ON(!(is_on ^ is_off));
+
+	for (o = rdt_options; o < &rdt_options[NUM_RDT_OPTIONS]; o++) {
+		if (!strcmp(name, o->name))
+			return (is_on && o->force_on) || (is_off && o->force_off);
+	}
+
+	return false;
+}
+
 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 0bbf991da981..aacaedcc7b74 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 {
  *                      gleaned from the XML files. Others are set from data
  *                      retrieved from intel_pmt_get_regions_by_feature().
  * @pfg:		The pmt_feature_group for this event group
+ * @name:		Name for this group
  * @guid:		Unique number per XML description file
  * @mmio_size:		Number of bytes of mmio registers for this group
  * @pkginfo:		Per-package MMIO addresses
@@ -57,6 +58,7 @@ struct pmt_event {
  */
 struct event_group {
 	struct pmt_feature_group	*pfg;
+	char				*name;
 	int				guid;
 	int				mmio_size;
 	struct mmio_info		**pkginfo;
@@ -66,6 +68,7 @@ struct event_group {
 
 /* Link: https://github.com/intel/Intel-PMT xml/CWF/OOBMSM/RMID-ENERGY *.xml */
 static struct event_group energy_0x26696143 = {
+	.name		= "energy",
 	.guid		= 0x26696143,
 	.mmio_size	= (576 * 2 + 3) * 8,
 	.num_events	= 2,
@@ -77,6 +80,7 @@ static struct event_group energy_0x26696143 = {
 
 /* Link: https://github.com/intel/Intel-PMT xml/CWF/OOBMSM/RMID-PERF *.xml */
 static struct event_group perf_0x26557651 = {
+	.name		= "perf",
 	.guid		= 0x26557651,
 	.mmio_size	= (576 * 7 + 3) * 8,
 	.num_events	= 7,
@@ -208,6 +212,8 @@ static bool get_pmt_feature(enum pmt_feature_id feature)
 	for (peg = &known_event_groups[0]; peg < &known_event_groups[NUM_KNOWN_GROUPS]; peg++) {
 		for (int i = 0; i < p->count; i++) {
 			if ((*peg)->guid == p->regions[i].guid) {
+				if (rdt_check_option((*peg)->name, false, true))
+					return false;
 				ret = configure_events((*peg), p);
 				if (ret) {
 					(*peg)->pfg = no_free_ptr(p);
-- 
2.48.1