kvmclock_test in ubuntu_kvm_unit_test failed with "offset too large!" with J-realtime on openstack AMD64

[Po-Hsu Lin]

kvmclock_test test in ubuntu_kvm_unit_test will fail with J-realtime on openstack amd64 instance. This issue can be seen after we start testing on openstack with 5.15.0-1036.39 in sru-20230320.

Test log:
 Running '/home/ubuntu/autotest/client/tmp/ubuntu_kvm_unit_tests/src/kvm-unit-tests/tests/kvmclock_test'
 BUILD_HEAD=d8edb59a
 timeout -k 1s --foreground 90s /usr/bin/qemu-system-x86_64 --no-reboot -nodefaults -device pc-testdev -device isa-debug-exit,iobase=0xf4,iosize=0x4 -vnc none -serial stdio -device pci-testdev -machine accel=tcg -kernel /tmp/tmp.iHaGzFDKoX -smp 2 --append 10000000 1685680818 # -initrd /tmp/tmp.9rLek97D5m
 enabling apic
 enabling apic
 smp: waiting for 1 APs
 setup: CPU 1 online
 kvm-clock: cpu 0, msr 0x51241c
 kvm-clock: cpu 1, msr 0x51243c
 Wallclock test, threshold 5
 Seconds get from host: 1685680818
 Raw nanoseconds value from kvmclock: 0 (cpu 0)
 Seconds get from kvmclock: 0 (cpu 0, offset: -1685680818)
 offset too large!
 Raw nanoseconds value from kvmclock: 0 (cpu 1)
 Seconds get from kvmclock: 0 (cpu 1, offset: -1685680818)
 offset too large!
 Check the stability of raw cycle ...
 Total vcpus: 2
 Test loops: 10000000
 Total warps: 0
 Total stalls: 19997725
 Worst warp: 0
 Raw cycle is stable
 Monotonic cycle test:
 Total vcpus: 2
 Test loops: 10000000
 Total warps: 0
 Total stalls: 19999698
 Worst warp: 0
 Measure the performance of raw cycle ...
 Total vcpus: 2
 Test loops: 10000000
 TSC cycles: 6497213250
 Measure the performance of adjusted cycle ...
 Total vcpus: 2
 Test loops: 10000000
 TSC cycles: 10223372850
 FAIL kvmclock_test

This issue still exist with the latest upstream kvm-unit-tests code (02d8befe99f8)
It's worthy to note that this test has passed with j/ibm on openstack amd64.