On 05.02.20 10:49, Wang, Wei W wrote:

On Wednesday, February 5, 2020 5:37 PM, David Hildenbrand wrote:

quoted

quoted

Not sure how TCG tracks the dirty bits. But In whatever
implementation, the hypervisor should have

There is only a single bitmap for that purpose. (well, the one where KVM
syncs to)

quoted

already dealt with the race between he current round and the previous

round dirty recording.

quoted

(the race isn't brought by this feature essentially)

It is guaranteed to work reliably without this feature as you only clear what
*has been migrated*, 

Not "clear what has been migrated" (that skips nothing..)
Anyway, it's a hint used for optimization.

Yes, an optimization that might easily lead to data corruption when the
two bitmaps are either not in place or don't play along in that specific
way (and I suspect this is the case under TCG).

-- 
Thanks,

David / dhildenb