Re: [PATCH rc v1 4/4] iommu/arm-smmu-v3-test: Add nested s1bypass coverage

[Shuai Xue]

在 2025/12/6 08:52, Nicolin Chen 写道:
> STE in a nested case requires both S1 and S2 fields. And this makes the use
> case different from the existing one.
>
> Add coverage for previously failed cases shifting between S2-only and S1+S2
> STEs.
>
> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
> ---
>   .../iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c  | 32 +++++++++++++++++++
>   1 file changed, 32 insertions(+)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
> index 9287904c93a2..56bdcf5a517e 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
> @@ -553,6 +553,36 @@ static void arm_smmu_v3_write_ste_test_s2_to_s1_stall(struct kunit *test)
>   						       NUM_EXPECTED_SYNCS(3));
>   }
>   
> +static void
> +arm_smmu_v3_write_ste_test_nested_s1dssbypass_to_s1bypass(struct kunit *test)
> +{
> +	struct arm_smmu_ste s1_ste;
> +	struct arm_smmu_ste s2_ste;
> +
> +	arm_smmu_test_make_s2_ste(&s1_ste, ARM_SMMU_MASTER_TEST_ATS);
> +	arm_smmu_test_make_cdtable_ste(&s1_ste, STRTAB_STE_1_S1DSS_SSID0,

arm_smmu_test_make_s2_ste() makes a s2 ste and it will be overwrited by
arm_smmu_test_make_cdtable_ste(). Finnaly, we got a s1 STE, not a nested
s1dssbypass ste.

I think we need a function like arm_smmu_make_nested_cd_table_ste()
here.

Besides, from the function name, I think you mean
STRTAB_STE_1_S1DSS_BYPASS?

+	arm_smmu_test_make_s2_ste(&s2_ste, 0);
+	arm_smmu_v3_test_ste_expect_hitless_transition(test, &s1_ste, &s2_ste,
+						       NUM_EXPECTED_SYNCS(3));

With get_ignored(), a nested s1dssbypass STE to a nested s1bypass STE
will be hitless, a.k.a, NUM_EXPECTED_SYNCS(1).

Thanks.
Shuai