Re: [PATCH v3 00/17] TCG Plugin inline operation enhancement

[Alex Bennée]

Pierrick Bouvier <pierrick.bouvier@linaro.org> writes:

> This series adds a new thread-safe API to declare inline operation
> inside plugins. As well, it removes the existing non thread-safe API,
> and migrates all existing plugins to use it.

I've cherry-picked 3 and 4 into plugins/next so I can re-base the
registers work. I'll have a look at the rest of the series once I'm back
at my desk.

>
> Tested on Linux (user, system) for i386, x86_64 and aarch64.
>
> To give some context, this a long term series of work around plugins,
> with the goal to be able to do basic operations in a more performant and
> accurate way. This will mean to add more inline operations and
> conditional callbacks.
>
> One final target of this work is to implement a plugin that implements
> the icount=auto feature, and allow QEMU to run at a given "frequency"
> based on number of instructions executed, without QEMU needing to keep
> track of this.
>
> Another final target is to be able to detect control flow changes in an
> efficient and elegant way, by combining inline operation and conditional
> callbacks.
>
> v2
> --
>
> Implement scoreboard API (cpu local storage), so plugins don't have to deal
> with how many cpus are used.
>
> Since plugins have been modified again, I didn't transfer any reviewed-by on
> those commits.
>
> v3
> --
>
> - introduce qemu_plugin_num_vcpus (how many cpus were initialized)
> - fix order of plugin init/idle/resume callbacks
> - scoreboard:
>   - renamed qemu_plugin_u64_t -> qemu_plugin_u64
>   - some functions rename for scoreboard api
>   - qemu_plugin_u64 has only value based function (vs address before)
> - various cleanup thanks to review of previous series
>
> Based-on: 20240122145610.413836-1-alex.bennee@linaro.org
>
>  Version number: 3
>  Branches:
>           base:  
> plugin_registers_v3_20240122145610.413836-1-alex.bennee@linaro.org
>           topic: plugin_inline_per_vcpu
>
>  To: qemu-devel@nongnu.org
>
>  Pierrick Bouvier (17):
>        plugins: remove previous n_vcpus functions from API
>        plugins: add qemu_plugin_num_vcpus function
>        plugins: fix order of init/idle/resume callback
>        cpu: call plugin init hook asynchronously
>        plugins: scoreboard API
>        docs/devel: plugins can trigger a tb flush
>        plugins: implement inline operation relative to cpu_index
>        plugins: add inline operation per vcpu
>        tests/plugin: add test plugin for inline operations
>        tests/plugin/mem: migrate to new per_vcpu API
>        tests/plugin/insn: migrate to new per_vcpu API
>        tests/plugin/bb: migrate to new per_vcpu API
>        contrib/plugins/hotblocks: migrate to new per_vcpu API
>        contrib/plugins/howvec: migrate to new per_vcpu API
>        plugins: remove non per_vcpu inline operation from API
>        plugins: cleanup codepath for previous inline operation
>        MAINTAINERS: Add myself as reviewer for TCG Plugins
>
>   MAINTAINERS                     |   1 +
>   docs/devel/multi-thread-tcg.rst |   1 +
>   include/qemu/plugin.h           |   6 ++
>   include/qemu/qemu-plugin.h      | 151 ++++++++++++++++++++++++--------
>   plugins/plugin.h                |  24 ++++--
>   accel/tcg/plugin-gen.c          |  65 +++++++++++---
>   contrib/plugins/cache.c         |   2 +-
>   contrib/plugins/hotblocks.c     |  50 ++++++-----
>   contrib/plugins/howvec.c        |  53 ++++++++----
>   hw/core/cpu-common.c            |   9 +-
>   plugins/api.c                   | 121 ++++++++++++++++----------
>   plugins/core.c                  | 104 +++++++++++++++++++---
>   tests/plugin/bb.c               |  63 ++++++--------
>   tests/plugin/inline.c           | 186 
> ++++++++++++++++++++++++++++++++++++++++
>   tests/plugin/insn.c             | 106 +++++++++++------------
>   tests/plugin/mem.c              |  40 +++++----
>   plugins/qemu-plugins.symbols    |  16 ++--
>   tests/plugin/meson.build        |   2 +-
>   18 files changed, 745 insertions(+), 255 deletions(-)
>
> Pierrick Bouvier (17):
>   plugins: remove previous n_vcpus functions from API
>   plugins: add qemu_plugin_num_vcpus function
>   plugins: fix order of init/idle/resume callback
>   cpu: call plugin init hook asynchronously
>   plugins: scoreboard API
>   docs/devel: plugins can trigger a tb flush
>   plugins: implement inline operation relative to cpu_index
>   plugins: add inline operation per vcpu
>   tests/plugin: add test plugin for inline operations
>   tests/plugin/mem: migrate to new per_vcpu API
>   tests/plugin/insn: migrate to new per_vcpu API
>   tests/plugin/bb: migrate to new per_vcpu API
>   contrib/plugins/hotblocks: migrate to new per_vcpu API
>   contrib/plugins/howvec: migrate to new per_vcpu API
>   plugins: remove non per_vcpu inline operation from API
>   plugins: cleanup codepath for previous inline operation
>   MAINTAINERS: Add myself as reviewer for TCG Plugins
>
>  MAINTAINERS                     |   1 +
>  docs/devel/multi-thread-tcg.rst |   1 +
>  include/qemu/plugin.h           |   6 ++
>  include/qemu/qemu-plugin.h      | 151 ++++++++++++++++++++------
>  plugins/plugin.h                |  24 +++--
>  accel/tcg/plugin-gen.c          |  65 +++++++++--
>  contrib/plugins/cache.c         |   2 +-
>  contrib/plugins/hotblocks.c     |  50 +++++----
>  contrib/plugins/howvec.c        |  53 ++++++---
>  hw/core/cpu-common.c            |   9 +-
>  plugins/api.c                   | 121 +++++++++++++--------
>  plugins/core.c                  | 104 ++++++++++++++++--
>  tests/plugin/bb.c               |  63 +++++------
>  tests/plugin/inline.c           | 186 ++++++++++++++++++++++++++++++++
>  tests/plugin/insn.c             | 106 +++++++++---------
>  tests/plugin/mem.c              |  40 ++++---
>  plugins/qemu-plugins.symbols    |  16 ++-
>  tests/plugin/meson.build        |   2 +-
>  18 files changed, 745 insertions(+), 255 deletions(-)
>  create mode 100644 tests/plugin/inline.c

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro