Re: [PATCH 0/16] lguest: introduce vcpu structure

From: Rusty Russell
Date: Sun Jan 06 2008 - 19:54:29 EST


On Monday 07 January 2008 04:33:53 Glauber de Oliveira Costa wrote:
> On Dec 25, 2007 9:54 PM, Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:
> > My only question is whether we should go further and vpu-ify routines
> > like lgread and kill_guest, so that we can avoid more "lg" temporary
> > variables...
>
> Essentially, they don't need it, because they only touch
> globally-visible variables (visible to the guest).
> So it's more of an stylish thing. Using the vcpu in the signature can
> have only one harm:
> It needs the caller to also have a pointer to a vcpu, so we may end up
> using it everywhere, like a domino fall.
>
> Alternatively, in such functions that don't currently receive a vcpu
> (nor they need to), we can convention to always pass
> lg->vcpus[0] to lgread, kill_guest, etc. Which one do you prefer?

I'm happy with a domino effect. I don't want to see lg->vcpus[0] *anywhere*
though, because it's non-futureproof.

When I looked through these patches it seems to me that we should accept that
vcpu is now the basic guest unit, and lg exists to serve it. Otherwise I
think you can see the bones of the old UP code poking through, and that's
ugly.

Thanks!
Rusty.
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