Re: rendezvousing all physical CPUs

[Keir Fraser <keir@xensource.com>]

On 30/11/06 16:14, "Jan Beulich" <jbeulich@novell.com> wrote:

> Will it be acceptable to create hypercall sub-functions (would probably go
> into the platform group, but should be architecture independent) to allow
> Dom0 to halt all physical CPUs but the current one, and later restart them?
> Or should it rather be a single call with an event-channel based call back
> to carry out the operation that must be protected?

How about providing the linear address of a chunk of dom0 code that Xen
should run in ring 0 with CPUs in a particular configuration? We could
provide flags to represent useful configurations: e.g., run on all CPUs
atomicaly, run on CPU0 only and quiesce others, etc.

As you say this could be used for things arguably more useful than this RNG
example, like microcode updates and maybe even the MTRR updates could be
done in dom0 too, which would be very nice. :-)

 -- Keir