Re: what is qemu_system_guest_panicked() for?

[Fabiano Rosas <farosas@suse.de>]

Peter Maydell <peter.maydell@linaro.org> writes:

> On Mon, 13 Jul 2026 at 15:49, Fabiano Rosas <farosas@suse.de> wrote:
>>
>> Peter Maydell <peter.maydell@linaro.org> writes:
>> >  - ppc TCG, in powerpc_checkstop(), for a machine check exception I think
>>
>> 1) The Checkstop state is the state the (modern) architecture prescribes
>> the machine transitions to when: a) machine check happens but machine
>> check exceptions are disabled or b) hard-to-recover storage errors. On
>> older user manuals I also see occurrences of checkstop when (a) above
>> happens and a "debug bit" is also set.
>>
>>   603 UM:
>>   "[cpu] must terminate operation by internally gating off all clocks, and
>>   release all outputs to the high impedance state"
>>
>>   750cx UM:
>>   "When a processor is in checkstop state, instruction processing is
>>   suspended and generally cannot resume without the processor being
>>   reset."
>
> Thanks. So since this is in TCG, is this for the case "we emulated
> the CPU ending up in a checkstop situation", rather than "the real
> host hardware is broken" ? Can the guest deliberately provoke real
> hardware into this state, or is it only something you can get into
> when the h/w is broken ?
>

The former, checkstop emulation. The guest cannot cause real hardware to
be in this state, this is the cosmic rays kind of problem.