On 08.02.2018 21:33, Eduardo Habkost wrote: > 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. > Right, the present patch effectively disables halted anyway (including s390). So it may be cleaner to just drop it right now. Assuming the presence of architecure-specific data, libvirt can derive a halted state (or an equivalent thereof) from query-cpus-fast returned information.
-- Regards, Viktor Mihajlovski
