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@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a8d0afde7f85a506b827ae31d48fc5d9dbabc095..abd77f39c783477cbb6c9f1815c36d2b1d11e643 100644 (file)
--- 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 2514f15cd9a447af76785cf57b1dfe34d6afd4ad..e38d7fc4f4276391c59313d924487596ff0fb331 100644 (file)
--- 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 9351fe5b645af1ae26bd0102cddcd1c16036b3e4..dc25e8d2527dc44cf6fbfc2514700d611cc16bda 100644 (file)
--- 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 3b228b241fb28c3a58cc9435f6db09399897b8c2..61a283652d3941dd70155c11db47fb0c746b464a 100644 (file)
--- 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 */