Re: [PATCH v3 9/9] KVM: riscv: selftests: Add sstc timer test

[Haibo Xu]

On Thu, Sep 14, 2023 at 5:52 PM Andrew Jones <ajones@xxxxxxxxxxxxxxxx> wrote:
>
> On Thu, Sep 14, 2023 at 09:37:03AM +0800, Haibo Xu wrote:
> > Add a KVM selftests to validate the Sstc timer functionality.
> > The test was ported from arm64 arch timer test.
>
> I just tried this test out. Running it over and over again on QEMU I see
> it works sometimes, but it frequently fails with the
> GUEST_ASSERT_EQ(config_iter + 1, irq_iter) assert and at least once I
> also saw the __GUEST_ASSERT(xcnt >= cmp) assert.
>

Good catch!

I can also reproduce this issue and it is a common problem for both
arm64 and riscv because it also happens in a arm64 Qemu VM.

It seems like a synchronization issue between host and guest shared
variables. Will double check the test code.

> Thanks,
> drew