On Tue, Jul 08, 2025, Srikanth Aithal wrote: > Hello all, > KVM unit test suite for SVM is regressing on the AMD EPYC Turin platform > (Zen 5) for a while now, even on latest linux-next[https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tag/?h= > next-20250704]. The same seem to work fine with linux-next tag > next-20250505. > The TSC delay test fails intermittently (approximately once in three runs) > with an unexpected result (expected: 50, actual: 49). This test passed > consistently on earlier tags (e.g., next-20250505) and on non-Turin > platforms. Stating the obvious to some extent, I suspect it's something to do with Turin, not a KVM issue. This fails on our Turin hosts as far back as v6.12, i.e. long before next-20250505 (I haven't bothered checking earlier builds), and AFAICT the KUT test isn't doing anything to actually stress KVM itself. I.e. I would expect KVM bugs to manifest as blatant, 100% reproducible failures, not random TSC slop. FAIL: tsc delay (expected: 50, actual: 49) SUMMARY: 13 tests, 1 unexpected failures ✘ ~/build/kut/x86 # uname -r 6.12.0-smp--adc218676eef-tsc
