Messages in this thread | | | Date | Fri, 14 Jan 2022 19:31:22 -0500 | Subject | Re: [PATCH v17 06/15] s390/vfio-ap: refresh guest's APCB by filtering APQNs assigned to mdev | From | Tony Krowiak <> |
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On 1/12/22 06:52, Halil Pasic wrote: > On Tue, 11 Jan 2022 16:19:06 -0500 > Tony Krowiak <akrowiak@linux.ibm.com> wrote: > >>> Also we could probably do the filtering incrementally. In a sense that >>> at a time only so much changes, and we know that the invariant was >>> preserved without that change. But that would probably end up trading >>> complexity for cycles. I will trust your judgment and your tests on this >>> matter. >> I am not entirely clear on what you are suggesting. I think you are >> suggesting that there may not be a need to look at every APQN >> assigned to the mdev when an adapter or domain is assigned or >> unassigned or a queue is probed or removed. Maybe you can clarify >> what you are suggesting here. > Exactly. For example if we have the following assigned > adapters: > 1, 2, 3 > domains: > 1, 2, 3 > and the operation we are trying to perform is assign domain 4, then it > is sufficient to have a look at the queues with the APQNs (1,4), (2,4) > and (3, 4). We don't have to examine all the 14 queues. > > When an unassign dapter is performed, there is no need to do the > re-filtering, because there is nothing that can pop-back or go away. And > on unassign domain is performed, then all we care about are the queues > of that domain on the filtered adapters. > > Similarly if after that successful assign the queue (3,4) gets removed > (from vfio_ap) and then added back again and probed, we only have to > look at the queues (3, 1), (3, 2), (3, 3). > > But I'm OK with the current design of this. It is certainly conceptually > simpler to say we have a master-copy and we filter that master-copy based > on the very same rules every time something changes. I'm really fine > either way as log as it works well. :D > > Regards, > Halil
I spent a day messing with this and was able to make it work, so the next implementation will incorporate your idea here.
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