On 05/07/2021 10:31, Jan Beulich wrote: > On 05.07.2021 11:25, Olaf Hering wrote: >> Am Mon, 5 Jul 2021 11:19:59 +0200 >> schrieb Jan Beulich <[email protected]>: >> >>> "The interface" being which one? The tool stack can map the guest's >>> grant table, so it is in the position to find out about all grants >>> without further hypervisor help. >> The interface means the code behind verify_frames. >> >> If there are indeed ways to query which pages belong to grants, how would >> the toolstack need to do that? > Map the grant table of the guest and walk it, recording any MFN for > which at least one valid r/w grant exists.
That doesn't help - Its still racy with in-flight IO. Also with updates from Xen such as the wallclocks. The only way to fix the IO problem is to disconnect the blk/net rings before doing the final sweep for frames, but that clobbers any ability to restart the VM on the source side if things go wrong at the destination. I don't have an answer at all for the vcpu info frames. ~Andrew
