Re: [PATCH] KVM: don't sent IPI if the vcpu is not online

[Avi Kivity]

 On 09/06/2010 04:48 AM, Xiao Guangrong wrote:
> On 09/05/2010 03:18 PM, Avi Kivity wrote:
> >   On 09/03/2010 07:12 AM, Xiao Guangrong wrote:
> > > It's no need sent IPI to the vcpu which is schedule out
> > >
> > >
> > > @@ -86,6 +86,7 @@ struct kvm_vcpu {
> > >        unsigned long requests;
> > >        unsigned long guest_debug;
> > >        int srcu_idx;
> > > +    bool online;
> > Why not check for guest_mode instead?
> Oh, i forget it...but 'vcpu->guest_mode' is only used in x86 platform,
> and make_all_cpus_request() is a common function.

We can have a function kvm_vcpu_guest_mode() that is defined differently 
for x86 and the other.

> So, maybe it's better use 'vcpu->online' here, and move 'guest_mode' into
> 'vcpu->arch' ?

I think guest_mode makes sense for the other archs for reducing IPIs, so 
let's leave it common and recommend that they implement it.  Alex, if 
you're ever bored.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

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