Re: [Xen-devel] [PATCH v2 19/21] xen/arm: introduce create_domUs

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 30 Jul 2018, Julien Grall wrote:
> Hi Stefano,
> 
> On 28/07/18 03:42, Stefano Stabellini wrote:
> > On Tue, 24 Jul 2018, Julien Grall wrote:
> > > > +
> > > > +            domain_unpause_by_systemcontroller(d);
> > > 
> > > If a domain is bound to CPU0, then it will not boot until CPU0 is done
> > > with
> > > creating domain. Is that what you want?
> > 
> > Are you suggesting to move the domain_unpause_by_systemcontroller(d) to
> > a second loop after the domU creation loop?
> 
> I was trying to understand what are the pro/cons of unpausing a DomU here. Did
> you explore it?

OK, let's dig into it.

domain_unpause_by_systemcontroller doesn't actually trigger a DomU boot
right away. It only marks the vcpu as ready to be started.  Then, it is
up to Xen wanting to leave hypervisor mode and start running a guest
vcpu. So there should be no issues in unpausing the vcpus here, in fact,
it should make no difference whether it is done inside this loop or on a
second loop.

In my experiments, cpu1 starts first, running dom1v0, then cpu0 (after
completely start_xen) running dom0v0.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel