Re: [RFC Patch] Support for making an E820 PCI hole in toolstack (xl + xm)

[Keir Fraser <keir@xen.org>]

On 15/11/2010 19:32, "Jeremy Fitzhardinge" <jeremy@goop.org> wrote:

>> Or, is there much disadvantage, to having a static really big PCI hole? Say
>> starting at 1GB? The advantage of this would be the ability to hotplug PCI
>> devices to a domU even across save/restore/migrate -- this may not work so
>> well if you commit yourself to the hole size of the original host, and the
>> restore/migrate target host has a bigger hole!
> 
> Well, the other question is whether the devices have to have the same
> pfn as mfn within the hole.  We're emulating the PCI config space anyway
> - couldn't we stick the passthrough PCI space at 3G regardless of where
> it is on the real hardware?

Well, I don't know. It sounds pretty sensible to me. :-)

Certain virtualisation feature sdisappearing after a save/restore/migrate --
or worsse, becoming unreliable -- would be a bit sad.

 -- Keir