Re: [Qemu-devel] [PATCH v2 3/4] uq/master: Add CPU eject handling for acpi_piix4

[Vasilis Liaskovitis]

On Thu, Jan 26, 2012 at 12:46:18PM +0200, Avi Kivity wrote:
> On 01/24/2012 04:56 PM, Vasilis Liaskovitis wrote:
> > On Tue, Jan 24, 2012 at 11:28:41AM +0100, Jan Kiszka wrote:
> > > On 2012-01-24 11:10, Vasilis Liaskovitis wrote:
> > > > Add stub functions for CPU eject callback. Define cpu_acpi_eject 
> > > > property and
> > > > enable eject callback only for pc-1.1 machine model.
> > > 
> > > Just to get the idea: What is the plan and advantage of introducing a
> > > stub first? How much more is required to have some usable feature, even
> > > if its just a friction of the full support?
> > >
> > There's not really an advantage to adding stubs first. The plan depends on 
> > the
> > lifecycle patches getting accepted in some form at some point. The code is 
> > all
> > out there, and some of it has been reviewed/commented on, but not accepted.
> >
> > kvm needs the following patches:
> > https://lkml.org/lkml/2012/1/6/355 (v7, still in work)
> > http://patchwork.ozlabs.org/patch/127828/
> > This second patch introduces ioctl KVM_SETSTATE_VCPU, (qemu uses it to 
> > signal
> > vcpu destruction to the host) but the review mentions there should be a
> > simpler way. It's unclear to me whether this ioctl is desired or not.
> 
> Those patches are not strictly needed.  On a kernel that doesn't have
> them, you can simply park the vcpu thread in userspace until it is
> re-added.  I suggest writing the qemu patches without the assumption
> that you're running on a 3.4+ kernel.

ok, I will try to handle CPU ejection without relying on the lifecycle
patches.

thanks,

- Vasilis