On Mon, Jul 21, 2025 at 7:00 AM Jiaqi Yan <jiaqiyan@xxxxxxxxxx> wrote:
>
> Hi Oliver,
>
> I was doing some SEA injection dev work and found
> tools/testing/selftests/kvm/arm64/external_aborts.c is failing at the
> head of my locally-tracked kvmarm/next, commit 811ec70dcf9cc ("Merge
> branch 'kvm-arm64/config-masks' into kvmarm/next"):
>
> vobeb33:/export/hda3/tmp/yjq# ./external_aborts
> Random seed: 0x6b8b4567
> test_mmio_abort <= fail
> ==== Test Assertion Failure ====
> arm64/external_aborts.c:19: regs->pc == expected_abort_pc
> pid=25675 tid=25675 errno=4 - Interrupted system call
> (stack trace empty)
> 0x0 != 0x21ed20 (regs->pc != expected_abort_pc)
> vobeb33:/export/hda3/tmp/yjq#
> vobeb33:/export/hda3/tmp/yjq#
> vobeb33:/export/hda3/tmp/yjq# ./external_aborts
> Random seed: 0x6b8b4567
> test_mmio_nisv <= pass
> test_mmio_nisv_abort <=fail
> ==== Test Assertion Failure ====
> arm64/external_aborts.c:19: regs->pc == expected_abort_pc
> pid=26153 tid=26153 errno=4 - Interrupted system call
> (stack trace empty)
> 0x0 != 0x21eb18 (regs->pc != expected_abort_pc)
>
> It looks like the PC in the guest register is lost / polluted. I only
> tested test_mmio_abort (fail), test_mmio_nisv (pass), and
> test_mmio_nisv_abort (fail), but from reading the code of
> test_mmio_nisv vs test_mmio_nisv_abort, I guess test failure is
> probably due to some bug in the code kvm injects SEA into guest.
>
> If I revert a single commit efa1368ba9f4 ("KVM: arm64: Commit
> exceptions from KVM_SET_VCPU_EVENTS immediately"), all tests in
> tools/testing/selftests/kvm/arm64/external_aborts.c pass. I have not
> yet figured out the bug tho. Want to report since you are the author
> maybe you can (or already) spot something.
Friendly ping ;)
>
> Thanks,
>
> Jiaqi
