[PATCH v6 0/3] Add support for the RAPL MSRs series

[Anthony Harivel <aharivel@redhat.com>]

Dear maintainers, 

First of all, thank you very much for your review of my patch 
[1].

In this version (v6), I have attempted to address all the problems 
addressed by Daniel and Paolo during the last review. 

However, two open questions remains unanswered that would require the 
attention of a x86 maintainers: 

1)Should I move from -kvm to -cpu the rapl feature ? [2]

2)Should I already rename to "rapl_vmsr_*" in order to anticipate the 
  futur TMPI architecture ? [end of 3] 

Thank you again for your continued guidance. 

v5 -> v6
--------
- Better error consistency in qio_channel_get_peerpid()
- Memory leak g_strdup_printf/g_build_filename corrected
- Renaming several struct with "vmsr_*" for better namespace
- Renamed several struct with "guest_*" for better comprehension
- Optimization suggerate from Daniel
- Crash problem solved [4]

v4 -> v5
--------

- correct qio_channel_get_peerpid: return pid = -1 in case of error
- Vmsr_helper: compile only for x86
- Vmsr_helper: use qio_channel_read/write_all
- Vmsr_helper: abandon user/group
- Vmsr_energy.c: correct all error_report
- Vmsr thread: compute default socket path only once
- Vmsr thread: open socket only once
- Pass relevant QEMU CI

v3 -> v4
--------

- Correct memory leaks with AddressSanitizer  
- Add sanity check for QEMU and qemu-vmsr-helper for checking if host is 
  INTEL and if RAPL is activated.
- Rename poor variables naming for easier comprehension
- Move code that checks Host before creating the VMSR thread
- Get rid of libnuma: create function that read sysfs for reading the 
  Host topology instead

v2 -> v3
--------

- Move all memory allocations from Clib to Glib
- Compile on *BSD (working on Linux only)
- No more limitation on the virtual package: each vCPU that belongs to 
  the same virtual package is giving the same results like expected on 
  a real CPU.
  This has been tested topology like:
     -smp 4,sockets=2
     -smp 16,sockets=4,cores=2,threads=2

v1 -> v2
--------

- To overcome the CVE-2020-8694 a socket communication is created
  to a priviliged helper
- Add the priviliged helper (qemu-vmsr-helper)
- Add SO_PEERCRED in qio channel socket

RFC -> v1
---------

- Add vmsr_* in front of all vmsr specific function
- Change malloc()/calloc()... with all glib equivalent
- Pre-allocate all dynamic memories when possible
- Add a Documentation of implementation, limitation and usage

Best regards,
Anthony

[1]: https://mail.gnu.org/archive/html/qemu-devel/2024-04/msg01570.html
[2]: https://mail.gnu.org/archive/html/qemu-devel/2024-04/msg03947.html
[3]: https://mail.gnu.org/archive/html/qemu-devel/2024-04/msg02350.html
[4]: https://mail.gnu.org/archive/html/qemu-devel/2024-04/msg02481.html

Anthony Harivel (3):
  qio: add support for SO_PEERCRED for socket channel
  tools: build qemu-vmsr-helper
  Add support for RAPL MSRs in KVM/Qemu

 accel/kvm/kvm-all.c                      |  27 ++
 contrib/systemd/qemu-vmsr-helper.service |  15 +
 contrib/systemd/qemu-vmsr-helper.socket  |   9 +
 docs/specs/index.rst                     |   1 +
 docs/specs/rapl-msr.rst                  | 155 +++++++
 docs/tools/index.rst                     |   1 +
 docs/tools/qemu-vmsr-helper.rst          |  89 ++++
 include/io/channel.h                     |  21 +
 include/sysemu/kvm_int.h                 |  32 ++
 io/channel-socket.c                      |  28 ++
 io/channel.c                             |  13 +
 meson.build                              |   7 +
 target/i386/cpu.h                        |   8 +
 target/i386/kvm/kvm.c                    | 431 +++++++++++++++++-
 target/i386/kvm/meson.build              |   1 +
 target/i386/kvm/vmsr_energy.c            | 337 ++++++++++++++
 target/i386/kvm/vmsr_energy.h            |  99 +++++
 tools/i386/qemu-vmsr-helper.c            | 530 +++++++++++++++++++++++
 tools/i386/rapl-msr-index.h              |  28 ++
 19 files changed, 1831 insertions(+), 1 deletion(-)
 create mode 100644 contrib/systemd/qemu-vmsr-helper.service
 create mode 100644 contrib/systemd/qemu-vmsr-helper.socket
 create mode 100644 docs/specs/rapl-msr.rst
 create mode 100644 docs/tools/qemu-vmsr-helper.rst
 create mode 100644 target/i386/kvm/vmsr_energy.c
 create mode 100644 target/i386/kvm/vmsr_energy.h
 create mode 100644 tools/i386/qemu-vmsr-helper.c
 create mode 100644 tools/i386/rapl-msr-index.h

-- 
2.45.1