Re: [RFC PATCH RESEND 00/42] accel/split/arm: Run EL2 using TCG and EL1/EL0 in hardware with HVF

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Cc'ing Salil

On 20/6/25 19:27, Philippe Mathieu-Daudé wrote:
> Hi,
> 
> This RFC is a proof-of-concept we can have QEMU run both software
> emulator (TCG) and hardware accelerator (here HVF). Unfortunately
> I'm exhausted so I'll let Alex explain what this is about,
> otherwise I'll post the real cover letter next Monday after
> getting some rest.
> 
> Full work available in the split-accel-rfc-v5 tag:
> https://gitlab.com/philmd/qemu/-/commits/split-accel-rfc-v5
> 
> Regards,
> 
> Phil.
> 
> Julian Armistead (1):
>    accel/split: Minimal stubs for split accelerator
> 
> Philippe Mathieu-Daudé (41):
>    accel/split: Define SplitAccelState
>    accel/split: Implement cpus_are_resettable()
>    accel/split: Implement accel_init_machine()
>    accel/split: Expose 'hw' and 'sw' properties
>    accel/split: Empty setup_post()
>    accel/split: Implement supports_guest_debug()
>    accel/split: Implement gdbstub_supported_sstep_flags()
>    accel/split: Add cpu_thread_routine() stub
>    accel/split: Define and allocate AccelCPUState
>    accel/split: Register MTTCG
>    accel/split: Have thread routine ready to dispatch over HW/SW
>    accel/split: Implement cpu_reset_hold()
>    accel/split: Implement synchronize_post_init()
>    accel/split: Implement synchronize_pre_resume()
>    accel/split: Implement synchronize_state()
>    accel/split: Implement synchronize_post_reset()
>    accel/split: Implement synchronize_pre_loadvm()
>    accel/split: Implement kick_vcpu_thread()
>    accel/split: Implement cpu_common_realize()
>    accel/split: Set use_hw in cpu_thread_routine() and switch over
>    accel/split: Add few trace events in cpu_thread_routine handler
>    target/arm: Implement SysemuCPUOps::can_accelerate() handler
>    accel/split: Implement handle_interrupt()
>    accel/split: Empty ops_init()
>    accel/split: Empty set/get_virtual_clock()
>    accel/split: Empty get_elapsed_ticks()
>    accel/split: Empty cpu_thread_is_idle()
>    accel/split: Kludge qemu_tcg_mttcg_enabled()
>    accel/split: Implement remove_all_breakpoints()
>    accel/split: Implement remove_breakpoint()
>    accel/split: Implement insert_breakpoint()
>    accel/split: Implement update_guest_debug()
>    accel/split: Implement get_[vcpu]_stats()
>    target/arm: Emulate EL2 under TCG
>    target/arm: Have ERET switch to hw accel for EL0/EL1
>    accel/hvf: Emulate HVC at EL2
>    accel/tcg: Introduce TCGCPUOps::rebuild_tb_hflags handler
>    target/arm: Implement TCGCPUOps::rebuild_tb_hflags()
>    accel/split: Call TCGCPUOps::rebuild_tb_hflags()
>    tests/functional: Add split_available() helper
>    tests/functional: Test Aarch64 virt machine with split-accelerator
> 
>   meson.build                                 |   1 +
>   accel/split/split-accel.h                   |  54 +++
>   accel/split/trace.h                         |   2 +
>   accel/tcg/internal-common.h                 |   1 +
>   include/accel/tcg/cpu-ops.h                 |   2 +
>   include/exec/cpu-common.h                   |   1 +
>   include/system/accel-ops.h                  |   8 +
>   target/arm/cpu.h                            |   2 +
>   accel/split/split-accel-ops.c               | 381 ++++++++++++++++++++
>   accel/split/split-all.c                     | 196 ++++++++++
>   accel/tcg/cpu-exec.c                        |   9 +
>   accel/tcg/tcg-accel-ops.c                   |   1 +
>   accel/tcg/tcg-all.c                         |   1 +
>   system/vl.c                                 |   4 +
>   target/arm/cpu.c                            |   9 +
>   target/arm/cpu64.c                          |   7 +-
>   target/arm/hvf/hvf.c                        |   6 +
>   target/arm/tcg/cpu-v7m.c                    |   1 +
>   target/arm/tcg/helper-a64.c                 |   9 +
>   target/arm/tcg/hflags.c                     |   5 +
>   accel/Kconfig                               |   6 +
>   accel/meson.build                           |   1 +
>   accel/split/meson.build                     |   9 +
>   accel/split/trace-events                    |   9 +
>   python/qemu/utils/__init__.py               |   3 +-
>   python/qemu/utils/accel.py                  |  10 +
>   tests/functional/meson.build                |   1 +
>   tests/functional/qemu_test/testcase.py      |   4 +-
>   tests/functional/test_aarch64_virt_split.py |  69 ++++
>   29 files changed, 808 insertions(+), 4 deletions(-)
>   create mode 100644 accel/split/split-accel.h
>   create mode 100644 accel/split/trace.h
>   create mode 100644 accel/split/split-accel-ops.c
>   create mode 100644 accel/split/split-all.c
>   create mode 100644 accel/split/meson.build
>   create mode 100644 accel/split/trace-events
>   create mode 100644 tests/functional/test_aarch64_virt_split.py
>