Re: [Qemu-devel] [RFC PATCH] target-arm/psci.c: wake up sleeping CPUs (MTTCG)

[Peter Maydell]

On 24 June 2015 at 18:18, Alex Bennée <address@hidden> wrote:
>
> Paolo Bonzini <address@hidden> writes:
>
>> On 24/06/2015 17:34, Alex Bennée wrote:
>>> Testing with Alexander's bare metal syncronisation tests fails in MTTCG
>>> leaving one CPU spinning forever waiting for the second CPU to wake up.
>>> We simply need to poke the halt_cond once we have processed the PSCI
>>> power on call.
>>>
>>> Tested-by: Alex Bennée <address@hidden>
>>> CC: Alexander Spyridakis <address@hidden>
>>>
>>> ---
>>> TODO
>>>   - exactly how does the vexpress wake up it's sleeping CPUs?
>>> ---
>>>  target-arm/psci.c | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/target-arm/psci.c b/target-arm/psci.c
>>> index d8fafab..661ff28 100644
>>> --- a/target-arm/psci.c
>>> +++ b/target-arm/psci.c
>>> @@ -196,6 +196,8 @@ void arm_handle_psci_call(ARMCPU *cpu)
>>>          }
>>>          target_cpu_class->set_pc(target_cpu_state, entry);
>>>
>>> +        qemu_cond_signal(target_cpu_state->halt_cond);
>>
>> That's called qemu_cpu_kick(target_cpu_state). :)  The patch should be
>> acceptable now upstream, I think.
>
> Oh so this might well fail in KVM too?

In KVM we won't use target-arm/psci.c because PSCI calls
are handled in the kernel.

-- PMM