Re: [Qemu-devel] [PATCH v2] qmp: add query-cpus-fast

[Eduardo Habkost <ehabkost@redhat.com>]

On Thu, Feb 08, 2018 at 11:17:32AM -0500, Luiz Capitulino wrote:
[...]
> The "halted" field is somewhat controversial. On the one hand,
> it offers a convenient way to know if a guest CPU is idle or
> running. On the other hand, it's a field that can change many
> times a second. In fact, the halted state can change even
> before query-cpus-fast has returned. This makes one wonder if
> this field should be dropped all together. Having the "halted"
> field as optional gives a better option for dropping it in
> the future, since we can just stop returning it.

I'd just drop it, unless we find a use case where it's really
useful.

Also, the code that sets/clears cpu->halted is target-specific,
so I wouldn't be so sure that simply checking for
!kvm_irqchip_in_kernel() is enough on all targets.

-- 
Eduardo