Re: [Xen-devel] PVH CPU hotplug design document

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 13 Jan 2017, Jan Beulich wrote:
> >>> On 12.01.17 at 13:13, <roger.pau@xxxxxxxxxx> wrote:
> > # Introduction
> > 
> > One of the design goals of PVH is to be able to remove as much Xen PV 
> > specific
> > code as possible, thus limiting the number of Xen PV interfaces used by 
> > guests,
> > and tending to use native interfaces (as used by bare metal) as much as
> > possible. This is in line with the efforts also done by Xen on ARM and helps
> > reduce the burden of maintaining huge amounts of Xen PV code inside of 
> > guests
> > kernels.
> > 
> > This however presents some challenges due to the model used by the Xen
> > Hypervisor, where some devices are handled by Xen while others are left for 
> > the
> > hardware domain to manage. The fact that Xen lacks and AML parser also 
> > makes it
> > harder, since it cannot get the full hardware description from dynamic ACPI
> > tables (DSDT, SSDT) without the hardware domain collaboration.
> 
> Considering all the difficulties with the proposed model plus the little
> code the PV vCPU hotplug logic requires in the kernel (assuming a
> xenbus driver to be there anyway), I'm rather unconvinced that
> going this route instead of sticking to the PV model is actually
> desirable. And clearly, for consistency within the kernel, in such a
> case I'd then also favor sticking to this model for DomU.

+1

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel