Re: [Qemu-devel] [PATCHv4 2/4] qmp: add query-cpus-fast

[Eric Blake <eblake@redhat.com>]

On 02/16/2018 08:49 AM, Viktor Mihajlovski wrote:

>>
>> The HMP changes are non-trivial compared to v3, so I might have dropped
>> all R-b and Acked-by to ensure they are looked at again.
>>
>> In fact,...
>>

>>> -
>>> -        if (cpu->value->CPU == monitor_get_cpu_index()) {
>>> -            active = '*';
>>> -        }
>>
>> The old code was doing multiple things - it was telling you the current
>> HMP cpu (HMP has 'cpu' with no QMP counterpart, but if you are using
>> HMP, knowing which cpu is the active target for future HMP commands that
>> depend on the active target, this bit of information is important),

>>
> Thanks for the patience. I'll respin with the r/a-b's on patch 2/4
> removed, but want to verify first that I can get the active cpu without
> triggering cpu_synchronize_state via monitor_get_cpu_index...

What does it matter?  HMP is not the time-critical interface like QMP, 
so even if it has to synchronize things, you're no worse off than you 
were before when using HMP.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org