[RFC PATCH 0/4] KVM: stats: Retrieve statistics data in binary format

[Jing Zhang <jingzhangos@google.com>]

This patchset extends IOCTL interface to retrieve KVM statistics data
in aggregated binary format.
It is meant to provide a lightweight, flexible, scalable and efficient 
lock-free solution for userspace telemetry applications to pull the
statistics data periodically for large scale systems.
The capability is indicated by KVM_CAP_STATS_BINARY_FORM.
Ioctl KVM_STATS_GET_INFO is used to get the information about VM or
vCPU statistics data (The number of supported statistics data which is
used for buffer allocation).
Ioctl KVM_STATS_GET_NAMES is used to get the list of name strings of
all supported statistics data.
Ioctl KVM_STATS_GET_DATA is used to get the aggregated statistics data
per VM or vCPU in the same order as the list of name strings. This is
the ioctl which would be called periodically to retrieve statistics
data per VM or vCPU.

Jing Zhang (4):
  KVM: stats: Separate statistics name strings from debugfs code
  KVM: stats: Define APIs for aggregated stats retrieval in binary
    format
  KVM: stats: Add ioctl commands to pull statistics in binary format
  KVM: selftests: Add selftest for KVM binary form statistics interface

 Documentation/virt/kvm/api.rst                |  79 +++++
 arch/arm64/kvm/guest.c                        |  47 ++-
 arch/mips/kvm/mips.c                          | 114 +++++--
 arch/powerpc/kvm/book3s.c                     | 107 ++++--
 arch/powerpc/kvm/booke.c                      |  84 +++--
 arch/s390/kvm/kvm-s390.c                      | 320 ++++++++++++------
 arch/x86/kvm/x86.c                            | 127 ++++---
 include/linux/kvm_host.h                      |  30 +-
 include/uapi/linux/kvm.h                      |  60 ++++
 tools/testing/selftests/kvm/.gitignore        |   1 +
 tools/testing/selftests/kvm/Makefile          |   3 +
 .../selftests/kvm/kvm_bin_form_stats.c        |  89 +++++
 virt/kvm/kvm_main.c                           | 115 +++++++
 13 files changed, 935 insertions(+), 241 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/kvm_bin_form_stats.c


base-commit: 357ad203d45c0f9d76a8feadbd5a1c5d460c638b
-- 
2.30.1.766.gb4fecdf3b7-goog