linux.git/arch/x86/kernel/cpu/resctrl/internal.h, branch v7.1 Linux kernel source tree Merge tag 'x86_cache_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2026-02-11T02:24:56+00:00 Linus Torvalds torvalds@linux-foundation.org 2026-02-11T02:24:56+00:00 dcb49710189d104d4edc07709615748dab61341b Pull x86 resource control updates from Borislav Petkov: - Extend the resctrl machinery to support telemetry monitoring on Intel (Tony Luck) The practical usage of this is being able to tell how much energy or how much work can be attributed to a group of tasks tracked under a single idenitifier. Prepend this work with proper refactoring of resctrl domains handling code. * tag 'x86_cache_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits) x86,fs/resctrl: Update documentation for telemetry events x86/resctrl: Enable RDT_RESOURCE_PERF_PKG fs/resctrl: Move RMID initialization to first mount x86,fs/resctrl: Compute number of RMIDs as minimum across resources fs/resctrl: Move allocation/free of closid_num_dirty_rmid[] x86/resctrl: Handle number of RMIDs supported by RDT_RESOURCE_PERF_PKG x86/resctrl: Add energy/perf choices to rdt boot option x86,fs/resctrl: Handle domain creation/deletion for RDT_RESOURCE_PERF_PKG fs/resctrl: Refactor rmdir_mondata_subdir_allrdtgrp() fs/resctrl: Refactor mkdir_mondata_subdir() x86/resctrl: Read telemetry events x86/resctrl: Find and enable usable telemetry events x86,fs/resctrl: Add architectural event pointer x86,fs/resctrl: Fill in details of events for performance and energy GUIDs x86/resctrl: Discover hardware telemetry events fs/resctrl: Emphasize that L3 monitoring resource is required for summing domains x86,fs/resctrl: Add and initialize a resource for package scope monitoring x86,fs/resctrl: Add an architectural hook called for first mount x86,fs/resctrl: Support binary fixed point event counters x86,fs/resctrl: Handle events that can be read from any CPU ... 
Pull x86 resource control updates from Borislav Petkov:

 - Extend the resctrl machinery to support telemetry monitoring on
   Intel (Tony Luck)

   The practical usage of this is being able to tell how much energy or
   how much work can be attributed to a group of tasks tracked under a
   single idenitifier. Prepend this work with proper refactoring of
   resctrl domains handling code.

* tag 'x86_cache_for_v7.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits)
  x86,fs/resctrl: Update documentation for telemetry events
  x86/resctrl: Enable RDT_RESOURCE_PERF_PKG
  fs/resctrl: Move RMID initialization to first mount
  x86,fs/resctrl: Compute number of RMIDs as minimum across resources
  fs/resctrl: Move allocation/free of closid_num_dirty_rmid[]
  x86/resctrl: Handle number of RMIDs supported by RDT_RESOURCE_PERF_PKG
  x86/resctrl: Add energy/perf choices to rdt boot option
  x86,fs/resctrl: Handle domain creation/deletion for RDT_RESOURCE_PERF_PKG
  fs/resctrl: Refactor rmdir_mondata_subdir_allrdtgrp()
  fs/resctrl: Refactor mkdir_mondata_subdir()
  x86/resctrl: Read telemetry events
  x86/resctrl: Find and enable usable telemetry events
  x86,fs/resctrl: Add architectural event pointer
  x86,fs/resctrl: Fill in details of events for performance and energy GUIDs
  x86/resctrl: Discover hardware telemetry events
  fs/resctrl: Emphasize that L3 monitoring resource is required for summing domains
  x86,fs/resctrl: Add and initialize a resource for package scope monitoring
  x86,fs/resctrl: Add an architectural hook called for first mount
  x86,fs/resctrl: Support binary fixed point event counters
  x86,fs/resctrl: Handle events that can be read from any CPU
  ...
x86/resctrl: Fix memory bandwidth counter width for Hygon 2026-01-13T15:44:26+00:00 Xiaochen Shen shenxiaochen@open-hieco.net 2025-12-09T06:26:50+00:00 7517e899e1b87b4c22a92c7e40d8733c48e4ec3c The memory bandwidth calculation relies on reading the hardware counter and measuring the delta between samples. To ensure accurate measurement, the software reads the counter frequently enough to prevent it from rolling over twice between reads. The default Memory Bandwidth Monitoring (MBM) counter width is 24 bits. Hygon CPUs provide a 32-bit width counter, but they do not support the MBM capability CPUID leaf (0xF.[ECX=1]:EAX) to report the width offset (from 24 bits). Consequently, the kernel falls back to the 24-bit default counter width, which causes incorrect overflow handling on Hygon CPUs. Fix this by explicitly setting the counter width offset to 8 bits (resulting in a 32-bit total counter width) for Hygon CPUs. Fixes: d8df126349da ("x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper") Signed-off-by: Xiaochen Shen <shenxiaochen@open-hieco.net> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20251209062650.1536952-3-shenxiaochen@open-hieco.net 
The memory bandwidth calculation relies on reading the hardware counter
and measuring the delta between samples. To ensure accurate measurement,
the software reads the counter frequently enough to prevent it from
rolling over twice between reads.

The default Memory Bandwidth Monitoring (MBM) counter width is 24 bits.
Hygon CPUs provide a 32-bit width counter, but they do not support the
MBM capability CPUID leaf (0xF.[ECX=1]:EAX) to report the width offset
(from 24 bits).

Consequently, the kernel falls back to the 24-bit default counter width,
which causes incorrect overflow handling on Hygon CPUs.

Fix this by explicitly setting the counter width offset to 8 bits (resulting
in a 32-bit total counter width) for Hygon CPUs.

Fixes: d8df126349da ("x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper")
Signed-off-by: Xiaochen Shen <shenxiaochen@open-hieco.net>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251209062650.1536952-3-shenxiaochen@open-hieco.net
x86/resctrl: Add energy/perf choices to rdt boot option 2026-01-09T22:38:32+00:00 Tony Luck tony.luck@intel.com 2025-12-17T17:21:11+00:00 842e7f97d71a4116a650ec0045d6444b4377b512 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 
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
x86,fs/resctrl: Handle domain creation/deletion for RDT_RESOURCE_PERF_PKG 2026-01-09T22:36:41+00:00 Tony Luck tony.luck@intel.com 2025-12-17T17:21:10+00:00 f4e0cd80d3e7c31327459008b01d63804838a89d The L3 resource has several requirements for domains. There are per-domain structures that hold the 64-bit values of counters, and elements to keep track of the overflow and limbo threads. None of these are needed for the PERF_PKG resource. The hardware counters are wide enough that they do not wrap around for decades. Define a new rdt_perf_pkg_mon_domain structure which just consists of the standard rdt_domain_hdr to keep track of domain id and CPU mask. Update resctrl_online_mon_domain() for RDT_RESOURCE_PERF_PKG. The only action needed for this resource is to create and populate domain directories if a domain is added while resctrl is mounted. Similarly resctrl_offline_mon_domain() only needs to remove domain directories. 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 
The L3 resource has several requirements for domains. There are per-domain
structures that hold the 64-bit values of counters, and elements to keep
track of the overflow and limbo threads.

None of these are needed for the PERF_PKG resource. The hardware counters
are wide enough that they do not wrap around for decades.

Define a new rdt_perf_pkg_mon_domain structure which just consists of the
standard rdt_domain_hdr to keep track of domain id and CPU mask.

Update resctrl_online_mon_domain() for RDT_RESOURCE_PERF_PKG. The only action
needed for this resource is to create and populate domain directories if a
domain is added while resctrl is mounted.

Similarly resctrl_offline_mon_domain() only needs to remove domain directories.

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
x86/resctrl: Read telemetry events 2026-01-09T22:02:57+00:00 Tony Luck tony.luck@intel.com 2025-12-17T17:21:07+00:00 51541f6ca7718d8278e12fe80af80033268743b2 Introduce intel_aet_read_event() to read telemetry events for resource RDT_RESOURCE_PERF_PKG. There may be multiple aggregators tracking each package, so scan all of them and add up all counters. Aggregators may return an invalid data indication if they have received no records for a given RMID. The user will see "Unavailable" if none of the aggregators on a package provide valid counts. Resctrl now uses readq() so depends on X86_64. Update Kconfig. 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 
Introduce intel_aet_read_event() to read telemetry events for resource
RDT_RESOURCE_PERF_PKG. There may be multiple aggregators tracking each
package, so scan all of them and add up all counters. Aggregators may return
an invalid data indication if they have received no records for a given RMID.
The user will see "Unavailable" if none of the aggregators on a package
provide valid counts.

Resctrl now uses readq() so depends on X86_64. Update Kconfig.

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
x86/resctrl: Discover hardware telemetry events 2026-01-09T15:37:07+00:00 Tony Luck tony.luck@intel.com 2026-01-08T17:42:26+00:00 1fb2daa60de640efb13f907d43d72d28763f696c Each CPU collects data for telemetry events that it sends to the nearest telemetry event aggregator either when the value of MSR_IA32_PQR_ASSOC.RMID changes, or when a two millisecond timer expires. There is a feature type ("energy" or "perf"), GUID, and MMIO region associated with each aggregator. This combination links to an XML description of the set of telemetry events tracked by the aggregator. XML files are published by Intel in a GitHub repository¹. The telemetry event aggregators maintain per-RMID per-event counts of the total seen for all the CPUs. There may be multiple telemetry event aggregators per package. There are separate sets of aggregators for each feature type. Aggregators in a set may have different GUIDs. All aggregators with the same feature type and GUID are symmetric keeping counts for the same set of events for the CPUs that provide data to them. The XML file for each aggregator provides the following information: 0) Feature type of the events ("perf" or "energy") 1) Which telemetry events are tracked by the aggregator. 2) The order in which the event counters appear for each RMID. 3) The value type of each event counter (integer or fixed-point). 4) The number of RMIDs supported. 5) Which additional aggregator status registers are included. 6) The total size of the MMIO region for an aggregator. Introduce struct event_group that condenses the relevant information from an XML file. Hereafter an "event group" refers to a group of events of a particular feature type (event_group::pfname set to "energy" or "perf") with a particular GUID. Use event_group::pfname to determine the feature id needed to obtain the aggregator details. It will later be used in console messages and with the rdt= boot parameter. The INTEL_PMT_TELEMETRY driver enumerates support for telemetry events. This driver provides intel_pmt_get_regions_by_feature() to list all available telemetry event aggregators of a given feature type. The list includes the "guid", the base address in MMIO space for the region where the event counters are exposed, and the package id where the all the CPUs that report to this aggregator are located. Call INTEL_PMT_TELEMETRY's intel_pmt_get_regions_by_feature() for each event group to obtain a private copy of that event group's aggregator data. Duplicate the aggregator data between event groups that have the same feature type but different GUID. Further processing on this private copy will be unique to the event group. ¹https://github.com/intel/Intel-PMT [ bp: Zap text explaining the code, s/guid/GUID/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 
Each CPU collects data for telemetry events that it sends to the nearest
telemetry event aggregator either when the value of MSR_IA32_PQR_ASSOC.RMID
changes, or when a two millisecond timer expires.

There is a feature type ("energy" or "perf"), GUID, and MMIO region associated
with each aggregator. This combination links to an XML description of the
set of telemetry events tracked by the aggregator. XML files are published
by Intel in a GitHub repository¹.

The telemetry event aggregators maintain per-RMID per-event counts of the
total seen for all the CPUs. There may be multiple telemetry event aggregators
per package.

There are separate sets of aggregators for each feature type. Aggregators
in a set may have different GUIDs. All aggregators with the same feature
type and GUID are symmetric keeping counts for the same set of events for
the CPUs that provide data to them.

The XML file for each aggregator provides the following information:
0) Feature type of the events ("perf" or "energy")
1) Which telemetry events are tracked by the aggregator.
2) The order in which the event counters appear for each RMID.
3) The value type of each event counter (integer or fixed-point).
4) The number of RMIDs supported.
5) Which additional aggregator status registers are included.
6) The total size of the MMIO region for an aggregator.

Introduce struct event_group that condenses the relevant information from
an XML file. Hereafter an "event group" refers to a group of events of a
particular feature type (event_group::pfname set to "energy" or "perf") with
a particular GUID.

Use event_group::pfname to determine the feature id needed to obtain the
aggregator details. It will later be used in console messages and with the
rdt= boot parameter.

The INTEL_PMT_TELEMETRY driver enumerates support for telemetry events.
This driver provides intel_pmt_get_regions_by_feature() to list all available
telemetry event aggregators of a given feature type. The list includes the
"guid", the base address in MMIO space for the region where the event counters
are exposed, and the package id where the all the CPUs that report to this
aggregator are located.

Call INTEL_PMT_TELEMETRY's intel_pmt_get_regions_by_feature() for each event
group to obtain a private copy of that event group's aggregator data. Duplicate
the aggregator data between event groups that have the same feature type
but different GUID. Further processing on this private copy will be unique
to the event group.

  ¹https://github.com/intel/Intel-PMT

  [ bp: Zap text explaining the code, s/guid/GUID/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
x86,fs/resctrl: Rename some L3 specific functions 2026-01-05T10:21:55+00:00 Tony Luck tony.luck@intel.com 2025-12-17T17:20:56+00:00 9c214d10c50990c7a61b95887493df9ae713eec5 With the arrival of monitor events tied to new domains associated with a different resource it would be clearer if the L3 resource specific functions are more accurately named. Rename three groups of functions: Functions that allocate/free architecture per-RMID MBM state information: arch_domain_mbm_alloc() -> l3_mon_domain_mbm_alloc() mon_domain_free() -> l3_mon_domain_free() Functions that allocate/free filesystem per-RMID MBM state information: domain_setup_mon_state() -> domain_setup_l3_mon_state() domain_destroy_mon_state() -> domain_destroy_l3_mon_state() Initialization/exit: rdt_get_mon_l3_config() -> rdt_get_l3_mon_config() resctrl_mon_resource_init() -> resctrl_l3_mon_resource_init() resctrl_mon_resource_exit() -> resctrl_l3_mon_resource_exit() Ensure kernel-doc descriptions of these functions' return values are present and correctly formatted. 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 
With the arrival of monitor events tied to new domains associated with a
different resource it would be clearer if the L3 resource specific functions
are more accurately named.

Rename three groups of functions:

Functions that allocate/free architecture per-RMID MBM state information:
arch_domain_mbm_alloc()		-> l3_mon_domain_mbm_alloc()
mon_domain_free()		-> l3_mon_domain_free()

Functions that allocate/free filesystem per-RMID MBM state information:
domain_setup_mon_state()	-> domain_setup_l3_mon_state()
domain_destroy_mon_state()	-> domain_destroy_l3_mon_state()

Initialization/exit:
rdt_get_mon_l3_config()		-> rdt_get_l3_mon_config()
resctrl_mon_resource_init()	-> resctrl_l3_mon_resource_init()
resctrl_mon_resource_exit()	-> resctrl_l3_mon_resource_exit()

Ensure kernel-doc descriptions of these functions' return values are present
and correctly formatted.

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
x86,fs/resctrl: Rename struct rdt_mon_domain and rdt_hw_mon_domain 2026-01-05T10:17:25+00:00 Tony Luck tony.luck@intel.com 2025-12-17T17:20:55+00:00 4bc3ef46ff41d5e7ba557e56e9cd2031527cd7f8 The upcoming telemetry event monitoring is not tied to the L3 resource and will have a new domain structure. Rename the L3 resource specific domain data structures to include "l3_" in their names to avoid confusion between the different resource specific domain structures: rdt_mon_domain -> rdt_l3_mon_domain rdt_hw_mon_domain -> rdt_hw_l3_mon_domain No functional change. 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 
The upcoming telemetry event monitoring is not tied to the L3 resource and
will have a new domain structure.

Rename the L3 resource specific domain data structures to include "l3_"
in their names to avoid confusion between the different resource specific
domain structures:
rdt_mon_domain		-> rdt_l3_mon_domain
rdt_hw_mon_domain	-> rdt_hw_l3_mon_domain

No functional change.

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
x86,fs/resctrl: Implement "io_alloc" enable/disable handlers 2025-11-21T21:35:22+00:00 Babu Moger babu.moger@amd.com 2025-11-13T00:57:30+00:00 556d2892aa715286d840a74216c8fff885559261 "io_alloc" is the generic name of the new resctrl feature that enables system software to configure the portion of cache allocated for I/O traffic. On AMD systems, "io_alloc" resctrl feature is backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). Introduce the architecture-specific functions that resctrl fs should call to enable, disable, or check status of the "io_alloc" feature. Change SDCIAE state by setting (to enable) or clearing (to disable) bit 1 of MSR_IA32_L3_QOS_EXT_CFG on all logical processors within the cache domain. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://patch.msgid.link/9e9070100c320eab5368e088a3642443dee95ed7.1762995456.git.babu.moger@amd.com 
"io_alloc" is the generic name of the new resctrl feature that enables system
software to configure the portion of cache allocated for I/O traffic. On AMD
systems, "io_alloc" resctrl feature is backed by AMD's L3 Smart Data Cache
Injection Allocation Enforcement (SDCIAE).

Introduce the architecture-specific functions that resctrl fs should call to
enable, disable, or check status of the "io_alloc" feature. Change SDCIAE state
by setting (to enable) or clearing (to disable) bit 1 of
MSR_IA32_L3_QOS_EXT_CFG on all logical processors within the cache domain.

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://patch.msgid.link/9e9070100c320eab5368e088a3642443dee95ed7.1762995456.git.babu.moger@amd.com
x86/resctrl: Configure mbm_event mode if supported 2025-09-15T10:52:04+00:00 Babu Moger babu.moger@amd.com 2025-09-05T21:34:31+00:00 0f1576e43adc62756879a240e66e89ce386b6eb9 Configure mbm_event mode on AMD platforms. On AMD platforms, it is recommended to use the mbm_event mode, if supported, to prevent the hardware from resetting counters between reads. This can result in misleading values or display "Unavailable" if no counter is assigned to the event. Enable mbm_event mode, known as ABMC (Assignable Bandwidth Monitoring Counters) on AMD, by default if the system supports it. Update ABMC across all logical processors within the resctrl domain to ensure proper functionality. Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com 
Configure mbm_event mode on AMD platforms. On AMD platforms, it is
recommended to use the mbm_event mode, if supported, to prevent the
hardware from resetting counters between reads. This can result in
misleading values or display "Unavailable" if no counter is assigned
to the event.

Enable mbm_event mode, known as ABMC (Assignable Bandwidth Monitoring
Counters) on AMD, by default if the system supports it.

Update ABMC across all logical processors within the resctrl domain to
ensure proper functionality.

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/cover.1757108044.git.babu.moger@amd.com