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Don't make a new request as doing so can stall >>> * the guest if reprogramming repeatedly fails. >>> */ >>> - if (reprogram_counter(pmc)) >>> + if (reprogram_counter(pmc) == -EBUSY) >>> set_bit(pmc->idx, pmu->reprogram_pmi); >>> } >>> >>> Though I guess one could argue -ENOMEM is also transient? >> >> I had contemplated this, but could not convince myself at a glance that >> perf and KVM agreed on what constituted a transient error. >> I have now concluded I was seeing ghosts :) >> >>> E.g. this? (completely untested) >>> [diff] >> >> Tested against the fault described in the linked patch and selftests on >> AMD Zen 3 (although I don't think there's much coverage in this regard). >> >> If no other objections, would you be fine with taking the diff you >> provided into the tree or would you prefer a v2? > > Go ahead and send a v2, I want to see what Sashiko thinks. >From a quick glance, it seems EBUSY and ENOMEM might just be sufficient. The former occurs when a pinned event cannot be created cause all counters are exhausted and the latter due to various event and context struct related alloc failures.