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Message-ID: <176807435671.510.2188274998747953660.tip-bot2@tip-bot2>
Date: Sat, 10 Jan 2026 19:45:56 -0000
From: "tip-bot2 for Tony Luck" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Tony Luck <tony.luck@...el.com>, "Borislav Petkov (AMD)" <bp@...en8.de>,
Reinette Chatre <reinette.chatre@...el.com>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject:
[tip: x86/cache] x86/resctrl: Add energy/perf choices to rdt boot option
The following commit has been merged into the x86/cache branch of tip:
Commit-ID: 842e7f97d71a4116a650ec0045d6444b4377b512
Gitweb: https://git.kernel.org/tip/842e7f97d71a4116a650ec0045d6444b4377b512
Author: Tony Luck <tony.luck@...el.com>
AuthorDate: Wed, 17 Dec 2025 09:21:11 -08:00
Committer: Borislav Petkov (AMD) <bp@...en8.de>
CommitterDate: Fri, 09 Jan 2026 23:38:32 +01:00
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.
A different approach is needed for hardware features that do not have an
X86_FEATURE_* flag.
Update parsing of the "rdt=" boot parameter to call the telemetry driver
directly to handle new "perf" and "energy" options that controls activation of
telemetry monitoring of the named type. By itself a "perf" or "energy" option
controls the forced enabling or disabling (with ! prefix) of all event groups
of the named type. A ":guid" suffix allows for fine grained control per event
group.
[ bp: s/intel_aet_option/intel_handle_aet_option/g ]
Signed-off-by: Tony Luck <tony.luck@...el.com>
Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com
---
Documentation/admin-guide/kernel-parameters.txt | 7 ++-
arch/x86/kernel/cpu/resctrl/core.c | 2 +-
arch/x86/kernel/cpu/resctrl/intel_aet.c | 38 ++++++++++++++++-
arch/x86/kernel/cpu/resctrl/internal.h | 2 +-
4 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a8d0afd..abd77f3 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6325,9 +6325,14 @@ Kernel parameters
rdt= [HW,X86,RDT]
Turn on/off individual RDT features. List is:
cmt, mbmtotal, mbmlocal, l3cat, l3cdp, l2cat, l2cdp,
- mba, smba, bmec, abmc, sdciae.
+ mba, smba, bmec, abmc, sdciae, energy[:guid],
+ perf[:guid].
E.g. to turn on cmt and turn off mba use:
rdt=cmt,!mba
+ To turn off all energy telemetry monitoring and ensure that
+ perf telemetry monitoring associated with guid 0x12345
+ is enabled use:
+ rdt=!energy,perf:0x12345
reboot= [KNL]
Format (x86 or x86_64):
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 2514f15..e38d7fc 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -814,6 +814,8 @@ static int __init set_rdt_options(char *str)
force_off = *tok == '!';
if (force_off)
tok++;
+ if (intel_handle_aet_option(force_off, tok))
+ continue;
for (o = rdt_options; o < &rdt_options[NUM_RDT_OPTIONS]; o++) {
if (strcmp(tok, o->name) == 0) {
if (force_off)
diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/resctrl/intel_aet.c
index 9351fe5..dc25e8d 100644
--- a/arch/x86/kernel/cpu/resctrl/intel_aet.c
+++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c
@@ -52,12 +52,17 @@ struct pmt_event {
/**
* struct event_group - Events with the same feature type ("energy" or "perf") and GUID.
* @pfname: PMT feature name ("energy" or "perf") of this event group.
+ * Used by boot rdt= option.
* @pfg: Points to the aggregated telemetry space information
* returned by the intel_pmt_get_regions_by_feature()
* call to the INTEL_PMT_TELEMETRY driver that contains
* data for all telemetry regions of type @pfname.
* Valid if the system supports the event group,
* NULL otherwise.
+ * @force_off: True when "rdt" command line or architecture code disables
+ * this event group.
+ * @force_on: True when "rdt" command line overrides disable of this
+ * event group.
* @guid: Unique number per XML description file.
* @mmio_size: Number of bytes of MMIO registers for this group.
* @num_events: Number of events in this group.
@@ -67,6 +72,7 @@ struct event_group {
/* Data fields for additional structures to manage this group. */
const char *pfname;
struct pmt_feature_group *pfg;
+ bool force_off, force_on;
/* Remaining fields initialized from XML file. */
u32 guid;
@@ -121,6 +127,35 @@ static struct event_group *known_event_groups[] = {
_peg < &known_event_groups[ARRAY_SIZE(known_event_groups)]; \
_peg++)
+bool intel_handle_aet_option(bool force_off, char *tok)
+{
+ struct event_group **peg;
+ bool ret = false;
+ u32 guid = 0;
+ char *name;
+
+ if (!tok)
+ return false;
+
+ name = strsep(&tok, ":");
+ if (tok && kstrtou32(tok, 16, &guid))
+ return false;
+
+ for_each_event_group(peg) {
+ if (strcmp(name, (*peg)->pfname))
+ continue;
+ if (guid && (*peg)->guid != guid)
+ continue;
+ if (force_off)
+ (*peg)->force_off = true;
+ else
+ (*peg)->force_on = true;
+ ret = true;
+ }
+
+ return ret;
+}
+
static bool skip_telem_region(struct telemetry_region *tr, struct event_group *e)
{
if (tr->guid != e->guid)
@@ -168,6 +203,9 @@ static bool enable_events(struct event_group *e, struct pmt_feature_group *p)
struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_PERF_PKG].r_resctrl;
int skipped_events = 0;
+ if (e->force_off)
+ return false;
+
if (!group_has_usable_regions(e, p))
return false;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 3b228b2..61a2836 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -236,6 +236,7 @@ void __exit intel_aet_exit(void);
int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val);
void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resource *r,
struct list_head *add_pos);
+bool intel_handle_aet_option(bool force_off, char *tok);
#else
static inline bool intel_aet_get_events(void) { return false; }
static inline void __exit intel_aet_exit(void) { }
@@ -246,6 +247,7 @@ static inline int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64
static inline void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resource *r,
struct list_head *add_pos) { }
+static inline bool intel_handle_aet_option(bool force_off, char *tok) { return false; }
#endif
#endif /* _ASM_X86_RESCTRL_INTERNAL_H */
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