Re: 'make check-tcg' fails with an assert in qemu_plugin_vcpu_init_hook

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

On 21/6/23 10:53, Peter Maydell wrote:
> On Wed, 21 Jun 2023 at 09:05, Alex Bennée <alex.bennee@linaro.org> wrote:
>>
>>
>> Peter Maydell <peter.maydell@linaro.org> writes:
>>
>>> On Tue, 20 Jun 2023 at 17:56, Peter Maydell <peter.maydell@linaro.org> wrote:
>>>>
>>>> $ make -C build/x86 check-tcg
>>>> make: Entering directory '/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/x86'
>>>> [...]
>>>>    TEST    munmap-pthread on arm
>>>> **
>>>> ERROR:../../plugins/core.c:221:qemu_plugin_vcpu_init_hook: assertion
>>>> failed: (success)
>>>> **
>>>> ERROR:../../accel/tcg/cpu-exec.c:1024:cpu_exec_setjmp: assertion
>>>> failed: (cpu == current_cpu)
>>>
>>> git bisect blames commit d7ee93e2435970:
>>>
>>>      cputlb: Restrict SavedIOTLB to system emulation
>>>
>>> I think that commit is not correct, because it means that
>>> the size of 'struct CPUState' and also the offset of fields
>>> like 'cpu_index' will be different for files which are
>>> compile-per-target-for-usermode and files which are
>>> compile-once-only. The assert happens here because the
>>> code which sets up cpu_index is build-once, but the code
>>> in qemu_plugin_vcpu_init_hook() which reads cpu_index is
>>> build-per-target and now they don't agree about where in
>>> the struct the field is...
>>
>> Hmm two things from that imply:
>>
>>    - I suspect the plugin core stuff could be build once (or maybe twice,
>>      system and user)
> 
> It is already build-once, that's why it goes wrong...
> 
>>    - we need to have some guard rails somehow to make sure things don't
>>      go out of sync
> 
> We do, this is the poison.h stuff. CONFIG_USER_ONLY is a
> special case which we don't poison because there would be
> too much refactoring required...

Just FYI the goal of the series including this commit is to remove
"exec/hwaddr.h" from user emulation.