When comparing the Focal 5.4 generic AMD64 kernel test output and Focal 5.4 KVM AMD64 kernel test output, you can see the generic kernel will pass with:
PASS: clflush (present) PASS: sfence (present) PASS: lfence (present) PASS: mfence (present) PASS: clflushopt (ABSENT) PASS: clwb (ABSENT) PASS: invalid clwb PASS: pcommit (ABSENT) SUMMARY: 8 tests PASS memory (8 tests)
Instead the KVM kernel will fail with: FAIL: clflushopt (ABSENT) FAIL: clwb (ABSENT)
I wonder what's the difference here.
When comparing the Focal 5.4 generic AMD64 kernel test output and Focal 5.4 KVM AMD64 kernel test output, you can see the generic kernel will pass with:
PASS: clflush (present)
PASS: sfence (present)
PASS: lfence (present)
PASS: mfence (present)
PASS: clflushopt (ABSENT)
PASS: clwb (ABSENT)
PASS: invalid clwb
PASS: pcommit (ABSENT)
SUMMARY: 8 tests
PASS memory (8 tests)
Instead the KVM kernel will fail with:
FAIL: clflushopt (ABSENT)
FAIL: clwb (ABSENT)
I wonder what's the difference here.