linux-kernel - Re: [PATCH 1/2] KVM: arm64: selftests: Disable single-step with correct KVM define

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Message-ID: <CAAeT=Fx1u=H=5xvmaPxnv4osNwAqNT5c_K1XTfwT0HiPucn+gg@mail.gmail.com>
Date:   Wed, 16 Nov 2022 19:07:22 -0800
From:   Reiji Watanabe <reijiw@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Marc Zyngier <maz@...nel.org>, James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
        kvmarm@...ts.cs.columbia.edu, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] KVM: arm64: selftests: Disable single-step with
 correct KVM define

On Wed, Nov 16, 2022 at 4:24 PM Sean Christopherson <seanjc@...gle.com> wrote:
>
> Disable single-step by setting debug.control to KVM_GUESTDBG_ENABLE,
> not to SINGLE_STEP_DISABLE.  The latter is an arbitrary test enum that
> just happens to have the same value as KVM_GUESTDBG_ENABLE, and so
> effectively disables single-step debug.
>
> No functional change intended.
>
> Cc: Reiji Watanabe <reijiw@...gle.com>
> Fixes: b18e4d4aebdd ("KVM: arm64: selftests: Add a test case for KVM_GUESTDBG_SINGLESTEP")
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  tools/testing/selftests/kvm/aarch64/debug-exceptions.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/kvm/aarch64/debug-exceptions.c b/tools/testing/selftests/kvm/aarch64/debug-exceptions.c
> index 947bd201435c..91f55b45dfc7 100644
> --- a/tools/testing/selftests/kvm/aarch64/debug-exceptions.c
> +++ b/tools/testing/selftests/kvm/aarch64/debug-exceptions.c
> @@ -369,7 +369,7 @@ void test_single_step_from_userspace(int test_cnt)
>                                                 KVM_GUESTDBG_SINGLESTEP;
>                                 ss_enable = true;
>                         } else {
> -                               debug.control = SINGLE_STEP_DISABLE;
> +                               debug.control = KVM_GUESTDBG_ENABLE;

Reviewed-by: Reiji Watanabe <reijiw@...gle.com>

Maybe I originally wanted to set it to 0:)
There is no issue with KVM_GUESTDBG_ENABLE at all,
as KVM_GUESTDBG_SINGLESTEP is cleared with that.

Thank you for fixing this!

Thanks,
Reiji


>                                 ss_enable = false;
>                         }
>
> --
> 2.38.1.431.g37b22c650d-goog
>