Re: [PATCH] KVM: Remove arch specific components from the general code

[Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>]

On Thu, 2007-07-26 at 14:05 +0300, Avi Kivity wrote:
> Rusty Russell wrote:
> > 	Great minds think alike.  This is a little rough, but I decided to send
> > it out tonight because it would make your life easier...
> 
> What about my life?  Which patch should I apply first?

Such are the responsibilities of command, Avi.

(Actually, the normal way is to send us both away to create a combined
patch set, and thus make it Not Your Problem).

> > ===
> > Dynamically allocate vcpus
> >
> > This patch converts the vcpus array in "struct kvm" to a linked list
> > of VCPUs, and changes the "vcpu_create" and "vcpu_setup" hooks into
> > one "vcpu_create" call which does the allocation and initialization of
> > the vcpu (calling back into the kvm_vcpu_init core helper).
> 
> Linked list?  So that the in-kernel apic code has to traverse a list, 
> making sure the cpu still knows how to transfer dirty cache lines for 
> every vcpu?
> 
> A good old fashioned pointer array will suit just fine.

So the in-kernel apic code has to traverse every element in the array?
That is clearly better because?  We get to place an artificial maximum
and keep a ceiling variable like the existing code does?

> > +	spin_lock(&kvm->lock);
> > +	/* What do we care if they create duplicate CPU ids?  But be nice. */
> >   
> 
> Oh, we care.  Esp. the apic code.

Yeah, I left the check although it's currently unneeded, but I still
don't think we should care.  We shouldn't use the cpu_id internally, but
use pointers.  Sure, the guest might get confused, by that's not the kvm
module's problem.

Thanks,
Rusty.


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