On Wed, Nov 29, 2017 at 01:07:32AM +0100, Paolo Bonzini wrote: > On 28/11/2017 15:08, Michael S. Tsirkin wrote: > > I think guests still want some way to halt when > > giving up CPU for a long time. > > > > If you are not worried about guests entering low power states, > > then you only need MWAIT and maybe PAUSE. > > > > HLT within guest only makes sense if you do not want to > > allow guest to enter power state. > > > > If you don't exit on any of these, you want some other way > > to actually halt the VCPU. > > If you want to do something in userspace, send a signal. Otherwise, it > doesn't really matter (if you have a dedicated physical CPU) whether the > task is runnable or not, as long as the CPU isn't in C0. > > Paolo If VCPU wants to give up its timeslice, how is it supposed to do it if all exits are blocked? -- MST
