timer in ubuntu_kvm_unit_tests failed on X-hwe ARM64 ThunderX

[Po-Hsu Lin]

Test skipped on Moonshot ARM64:
SKIP timer (KVM acceleration is probably not supported)

But failed on ThunderX instead:
FAIL: ptimer-busy-loop: interrupt received after TVAL/WFI

# TESTNAME=timer TIMEOUT=2s ACCEL= ./arm/run arm/timer.flat -smp 1
timeout -k 1s --foreground 2s /usr/bin/qemu-system-aarch64 -nodefaults -machine virt,gic-version=host,accel=kvm -cpu host -device virtio-serial-device -device virtconsole,chardev=ctd -chardev testdev,id=ctd -device pci-testdev -display none -serial stdio -kernel arm/timer.flat -smp 1 # -initrd /tmp/tmp.j0n8ycjpmW
CNTFRQ_EL0 : 0x0000000005f5e100
CNTPCT_EL0 : 0x00000023cc22210f
CNTP_CTL_EL0 : 0x0000000000000004
CNTP_CVAL_EL0: 0x0000000000000000
CNTVCT_EL0 : 0x00000000007c1236
CNTV_CTL_EL0 : 0x0000000000000000
CNTV_CVAL_EL0: 0x0000000000000000
PASS: vtimer-busy-loop: not pending before
PASS: vtimer-busy-loop: interrupt signal pending
INFO: vtimer-busy-loop: After timer: 0x0000000000986769
INFO: vtimer-busy-loop: Expected : 0x0000000000986768
INFO: vtimer-busy-loop: Difference : 0 us
PASS: vtimer-busy-loop: latency within 10 ms
PASS: vtimer-busy-loop: interrupt received
PASS: vtimer-busy-loop: interrupt received after TVAL/WFI
PASS: vtimer-busy-loop: timer has expired (-7286)
PASS: ptimer-busy-loop: not pending before
PASS: ptimer-busy-loop: interrupt signal pending
INFO: ptimer-busy-loop: After timer: 0x00000023cc81dceb
INFO: ptimer-busy-loop: Expected : 0x00000023cc81cf88
INFO: ptimer-busy-loop: Difference : 34 us
PASS: ptimer-busy-loop: latency within 10 ms
PASS: ptimer-busy-loop: interrupt received
FAIL: ptimer-busy-loop: interrupt received after TVAL/WFI
PASS: ptimer-busy-loop: timer has expired (-5367)
SUMMARY: 12 tests, 1 unexpected failures

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.15.0-48-generic 4.15.0-48.51~16.04.1
ProcVersionSignature: User Name 4.15.0-48.51~16.04.1-generic 4.15.18
Uname: Linux 4.15.0-48-generic aarch64
ApportVersion: 2.20.1-0ubuntu2.18
Architecture: arm64
Date: Wed May 8 04:17:41 2019
SourcePackage: linux-hwe
UpgradeStatus: No upgrade log present (probably fresh install)

[Po-Hsu Lin (cypressyew)]

This test has passed with Xenial 4.4 kernel.
So this feels like a kernel issue to me.

[Po-Hsu Lin (cypressyew)]

Passed on node "starmie" (ThunderX) on X:

TESTNAME=timer TIMEOUT=2s ACCEL= ./arm/run arm/timer.flat -smp 1
PASS timer (7 tests, 1 skipped)