On 05.07.2021 10:02, Olaf Hering wrote: > Am Mon, 5 Jul 2021 09:57:21 +0200 > schrieb Jan Beulich <[email protected]>: > >> What is "the grant problem" referring to here? Neither anything above >> nor the offending original commit has any reference to grants, or a >> problem with them. > > When the guest is paused during final transit, the backends will > continue to write into domU memory. As a result the final additional > iteration to verify memory on both sides will always see errors.
I see. A similar problem then exists with at least the FIFO event channel per-vCPU control blocks? > The code has no way to know for which pfn such mismatches in page > content can safely be ignored. Well, in principle this can be known, but it's expensive: For a paused domain the grant table can't change anymore. Any pages referenced by a valid non-r/o grant table entry could in principle change. Jan
