On 21/11/14 09:43, Ian Campbell wrote:

On Thu, 2014-11-20 at 18:28 +0000, Andrew Cooper wrote:

Realistically, this means no updates to the
p2m at all, due to several potential race conditions.

From the rest of the mail it seems as if you are talking primarily about
changes to the p2m *structure*, i.e. which guest frames contain the p2m
pages, rather than changes to the p2m entries themselves. Is that
correct?

I cover both, although the structure changes are the more obvious, and more complicated to fix.

There are race conditions in both existing implementation between a p2m/m2p update and the toolstack sampling the dirty bitmap where stale frames don't get resent.


I don't see any (explicit) mention of the pfn_to_mfn_frame_list_list
here, where does that fit in?

It is referenced several times, although not by its exact name.

~Andrew