[PATCH v11 00/14] machine: smp parsing fixes and improvement

[Yanan Wang]

Hi,

This is a new version (v11) with some update in patch 11/14 suggested
by Daniel. Please have another look, Thanks!

Summary of v11:
1) Specifying a CPU topology parameter as zero was implicitly allowed
but undocumented before, while now it's explicitly deprecated.

2) Refactor/fixes of the smp parsers.

3) For consistency, maxcpus is now uniformly used to calculate the
omitted topology members.

4) Improve the error reporting of the parsers.

5) It's also suggested that we should start to prefer cores over sockets
over threads on the newer machine types, which will make the computed
virtual topology more reflective of the real hardware. Related discussion
can be found in [1].
[1] https://lore.kernel.org/qemu-devel/YNIgInK00yNNI4Dy@redhat.com/

6) In order to reduce code duplication and ease the code maintenance,
smp_parse() is converted into a generic enough parser for all arches,
so that the arch-specific ones (e.g. pc_smp_parse) can be removed.
It's also convenient to introduce more topology members to the generic
parser in the future. Related discussions can be found in [2] and [3].
[2] 
https://lore.kernel.org/qemu-devel/20210630115602.txmvmfe2jrzu7o67@gator.home/
[3] https://lore.kernel.org/qemu-devel/YPFN83pKBt7F97kW@redhat.com/

Changelogs:

v10->v11:
- only update patch 11/14
  use GString APIs to build the cpu topology hierarchy string (Daniel)
  refine the comments of smp_parse()
- v10: 
20210926084541.17352-1-wangyanan55@huawei.com/">https://lore.kernel.org/qemu-devel/20210926084541.17352-1-wangyanan55@huawei.com/

v9->v10:
- rebased on latest upstream commit 11a1199846.
  there is no change of the patches in v10, except minor update
  in 08/14 to resolve merge conflict with master.
- To make this series more acceptable, drop the last two patches
  about SMP unit test, since the scalability of the test is not
  optimally designed after rethinking of it. So I will resend the
  test related patches separately after refining them.
- v9: 
20210910073025.16480-1-wangyanan55@huawei.com/">https://lore.kernel.org/qemu-devel/20210910073025.16480-1-wangyanan55@huawei.com/

Yanan Wang (14):
  machine: Deprecate "parameter=0" SMP configurations
  machine: Minor refactor/fix for the smp parsers
  machine: Uniformly use maxcpus to calculate the omitted parameters
  machine: Set the value of cpus to match maxcpus if it's omitted
  machine: Improve the error reporting of smp parsing
  qtest/numa-test: Use detailed -smp CLIs in pc_dynamic_cpu_cfg
  qtest/numa-test: Use detailed -smp CLIs in test_def_cpu_split
  machine: Prefer cores over sockets in smp parsing since 6.2
  machine: Use ms instead of global current_machine in sanity-check
  machine: Tweak the order of topology members in struct CpuTopology
  machine: Make smp_parse generic enough for all arches
  machine: Remove smp_parse callback from MachineClass
  machine: Move smp_prefer_sockets to struct SMPCompatProps
  machine: Put all sanity-check in the generic SMP parser

 docs/about/deprecated.rst  |  15 +++
 hw/arm/virt.c              |   1 +
 hw/core/machine.c          | 195 ++++++++++++++++++++++++++-----------
 hw/i386/pc.c               |  63 +-----------
 hw/i386/pc_piix.c          |   1 +
 hw/i386/pc_q35.c           |   1 +
 hw/ppc/spapr.c             |   1 +
 hw/s390x/s390-virtio-ccw.c |   1 +
 include/hw/boards.h        |  23 +++--
 qapi/machine.json          |   2 +-
 qemu-options.hx            |  24 +++--
 tests/qtest/numa-test.c    |   6 +-
 12 files changed, 195 insertions(+), 138 deletions(-)

--
2.19.1