[PATCH v4 00/13] x86/resctrl: Support for AMD QoS new features and bug fix

[Babu Moger]

New AMD processors can now support following QoS features.

1. Slow Memory Bandwidth Allocation (SMBA)
   With this feature, the QOS enforcement policies can be applied
   to the external slow memory connected to the host. QOS enforcement
   is accomplished by assigning a Class Of Service (COS) to a processor
   and specifying allocations or limits for that COS for each resource
   to be allocated.

   Currently, CXL.memory is the only supported "slow" memory device. With
   the support of SMBA feature the hardware enables bandwidth allocation
   on the slow memory devices.

2. Bandwidth Monitoring Event Configuration (BMEC)
   The bandwidth monitoring events mbm_total_event and mbm_local_event 
   are set to count all the total and local reads/writes respectively.
   With the introduction of slow memory, the two counters are not enough
   to count all the different types are memory events. With the feature
   BMEC, the users have the option to configure mbm_total_event and
   mbm_local_event to count the specific type of events.

   Following are the bitmaps of events supported.
   Bits    Description
     6       Dirty Victims from the QOS domain to all types of memory
     5       Reads to slow memory in the non-local NUMA domain
     4       Reads to slow memory in the local NUMA domain
     3       Non-temporal writes to non-local NUMA domain
     2       Non-temporal writes to local NUMA domain
     1       Reads to memory in the non-local NUMA domain
     0       Reads to memory in the local NUMA domain

This series adds support for these features. Added a bug fix and a code cleanup.

Feature description is available in the specification, "AMD64 Technology Platform Quality
of Service Extensions, Revision: 1.03 Publication # 56375 Revision: 1.03 Issue Date: February 2022".

Link: https://www.amd.com/en/support/tech-docs/amd64-technology-platform-quality-service-extensions
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537

---
4:
  Got numerios of comments from Reinette Chatre. Addressed most of them. 
  Summary of changes.
  1. Removed mon_configurable under /sys/fs/resctrl/info/L3_MON/.  
  2. Updated mon_features texts if the BMEC is supported.
  3. Added more explanation about the slow memory support.
  4. Replaced smp_call_function_many with on_each_cpu_mask call.
  5. Removed arch_has_empty_bitmaps
  6. Few other text changes.
  7. Removed Reviewed-by if the patch is modified.
  8. Rebased the patches to latest tip.

v3:
  https://lore.kernel.org/lkml/166117559756.6695.16047463526634290701.stgit@bmoger-ubuntu/ 
  a. Rebased the patches to latest tip. Resolved some conflicts.
     https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
  b. Taken care of feedback from Bagas Sanjaya.
  c. Added Reviewed by from Mingo.
  Note: I am still looking for comments from Reinette or Fenghua.

v2:
  https://lore.kernel.org/lkml/165938717220.724959.10931629283087443782.stgit@bmoger-ubuntu/
  a. Rebased the patches to latest stable tree (v5.18.15). Resolved some conflicts.
  b. Added the patch to fix CBM issue on AMD. This was originally discussed
     https://lore.kernel.org/lkml/20220517001234.3137157-1-eranian@xxxxxxxxxx/

v1:
  https://lore.kernel.org/lkml/165757543252.416408.13547339307237713464.stgit@bmoger-ubuntu/

Babu Moger (13):
      x86/resctrl: Fix min_cbm_bits for AMD
      x86/resctrl: Remove arch_has_empty_bitmaps
      x86/cpufeatures: Add Slow Memory Bandwidth Allocation feature flag
      x86/resctrl: Add a new resource type RDT_RESOURCE_SMBA
      x86/cpufeatures: Add Bandwidth Monitoring Event Configuration feature flag
      x86/resctrl: Include new features in command line options
      x86/resctrl: Detect and configure Slow Memory Bandwidth allocation
      x86/resctrl : Introduce data structure to support monitor configuration
      x86/resctrl: Add sysfs interface files to read/write event configuration
      x86/resctrl: Add the sysfs interface to read the event configuration
      x86/resctrl: Add sysfs interface to write the event configuration
      x86/resctrl: Replace smp_call_function_many with on_each_cpu_mask
      Documentation/x86: Update resctrl_ui.rst for new features


 .../admin-guide/kernel-parameters.txt         |   2 +-
 Documentation/x86/resctrl.rst                 | 148 +++++++++-
 arch/x86/include/asm/cpufeatures.h            |   2 +
 arch/x86/kernel/cpu/resctrl/core.c            |  58 +++-
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c     |   5 +-
 arch/x86/kernel/cpu/resctrl/internal.h        |  32 ++-
 arch/x86/kernel/cpu/resctrl/monitor.c         |   9 +-
 arch/x86/kernel/cpu/resctrl/rdtgroup.c        | 272 +++++++++++++++---
 arch/x86/kernel/cpu/scattered.c               |   2 +
 include/linux/resctrl.h                       |   6 +-
 10 files changed, 479 insertions(+), 57 deletions(-)

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