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Message-ID: <20250711235341.113933-25-tony.luck@intel.com>
Date: Fri, 11 Jul 2025 16:53:31 -0700
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghuay@...dia.com>,
Reinette Chatre <reinette.chatre@...el.com>,
Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>,
Peter Newman <peternewman@...gle.com>,
James Morse <james.morse@....com>,
Babu Moger <babu.moger@....com>,
Drew Fustini <dfustini@...libre.com>,
Dave Martin <Dave.Martin@....com>,
Anil Keshavamurthy <anil.s.keshavamurthy@...el.com>,
Chen Yu <yu.c.chen@...el.com>
Cc: x86@...nel.org,
linux-kernel@...r.kernel.org,
patches@...ts.linux.dev,
Tony Luck <tony.luck@...el.com>
Subject: [PATCH v7 24/31] x86/resctrl: Add energy/perf choices to rdt boot option
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@...el.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
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