[v3,0/4] KVM: arm64: selftests: Add edge cases tests for the arch timer

Message

Ricardo Koller March 22, 2022, 5:23 p.m. UTC

Add a new selftests that validates some edge cases related to the virtual
arch-timer, for example:
- timers across counter roll-overs.
- moving counters ahead and behind pending timers.
- having the same timer condition firing multiple times.

The tests run while checking the state of the IRQs (e.g., pending when they
are supposed to be) and stressing things a bit by waiting for interrupts
while: re-scheduling the vcpu (with sched_yield()), by migrating the vcpu
between cores, or by sleeping in userspace (with usleep()).

The first commit adds a timer utility function.  The second commit adds
some sanity checks and basic tests for the timer. The third commit adds
the actual edge case tests (like forcing rollovers).

v2 -> v3:
- Add missing isb when polling for IRQ being handled. [Oliver, Marc]
- Wait for a counter pass by polling on it (instead of the previous isb).
  [Oliver, Marc]
- Edits in some comments. [Oliver]
- Dropping the msecs_to_usecs macro. [Oliver]
- Skipping test if desired pcpus are not online. This needed adding a
  library function (is_cpu_online). [Oliver]

v1 -> v2: https://lore.kernel.org/kvmarm/[e-mail]/
- Remove the checks for timers firing within some margin; only leave the
  checks for timers not firing ahead of time. Also remove the tests that
  depend on timers firing within some margin. [Oliver, Marc]
- Collect R-b tag from Oliver (first commit). [Oliver]
- Multiple nits: replace wfi_ functions with wait_, reduce use of macros,
  drop typedefs, use IAR_SPURIOUS from header, move some comments functions
  to top. [Oliver]
- Don't fail if the test has a single cpu available. [Oliver]
- Don't fail if there's no GICv3 available. [Oliver]

v1: https://lore.kernel.org/kvmarm/[e-mail]/

Ricardo Koller (4):
  KVM: arm64: selftests: add timer_get_tval() lib function
  KVM: selftests: add is_cpu_online() utility function
  KVM: arm64: selftests: add arch_timer_edge_cases
  KVM: arm64: selftests: add edge cases tests into arch_timer_edge_cases

 tools/testing/selftests/kvm/.gitignore        |   1 +
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../kvm/aarch64/arch_timer_edge_cases.c       | 904 ++++++++++++++++++
 .../kvm/include/aarch64/arch_timer.h          |  18 +-
 .../testing/selftests/kvm/include/test_util.h |   2 +
 tools/testing/selftests/kvm/lib/test_util.c   |  16 +
 6 files changed, 941 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/kvm/aarch64/arch_timer_edge_cases.c