On Sat, 2011-05-21 at 09:44 +0100, James Harper wrote:
Am I understanding right that the OS would need to be completely put on hold in the middle of the hypercall while the BIOS took over and did it's shutdown sequence, which presumably involves xenstore activity?
Correct, or at least that is one suggestion (probably the front runner at the moment).
In theory it's no worse than SMM, which Windows presumably already copes with, but perhaps the latency from having to do the xenstore interaction is far greater than any real SMM operation.
How hard would it be to create a better mechanism for going forward and implement the above as a fallback if the DomU doesn't support the new mechanism?