Re: [PATCH rc v2 4/4] iommu/arm-smmu-v3-test: Add nested s1bypass/s1dssbypass coverage

[Shuai Xue <xueshuai@linux.alibaba.com>]

在 2025/12/8 04:49, 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@nvidia.com>
> ---
>   .../iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c  | 61 +++++++++++++++++++
>   1 file changed, 61 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 3556e65cf9ac..1672e75ebffc 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
> @@ -555,6 +555,65 @@ static void arm_smmu_v3_write_ste_test_s2_to_s1_stall(struct kunit *test)
>   						       NUM_EXPECTED_SYNCS(3));
>   }
>   
> +static void arm_smmu_test_make_nested_cdtable_ste(
> +	struct arm_smmu_ste *ste, unsigned int s1dss, const dma_addr_t dma_addr,
> +	enum arm_smmu_test_master_feat feat)
> +{
> +	bool stall_enabled = feat & ARM_SMMU_MASTER_TEST_STALL;
> +	bool ats_enabled = feat & ARM_SMMU_MASTER_TEST_ATS;
> +	struct arm_smmu_ste s1ste;
> +
> +	struct arm_smmu_master master = {
> +		.ats_enabled = ats_enabled,
> +		.cd_table.cdtab_dma = dma_addr,
> +		.cd_table.s1cdmax = 0xFF,
> +		.cd_table.s1fmt = STRTAB_STE_0_S1FMT_64K_L2,
> +		.smmu = &smmu,
> +		.stall_enabled = stall_enabled,
> +	};
> +
> +	arm_smmu_test_make_s2_ste(ste, ARM_SMMU_MASTER_TEST_ATS);
> +	arm_smmu_make_cdtable_ste(&s1ste, &master, ats_enabled, s1dss);

Hi, Nicolin,

Nit. Instead of duplicating this code, we can leverage the existing
arm_smmu_test_make_cdtable_ste() helper here.

> +
> +	ste->data[0] = cpu_to_le64(
> +		STRTAB_STE_0_V |
> +		FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_NESTED));
> +	ste->data[0] |= s1ste.data[0] & ~cpu_to_le64(STRTAB_STE_0_CFG);
> +	ste->data[1] |= s1ste.data[1];
> +	/* Merge events for DoS mitigations on eventq */
> +	ste->data[1] |= cpu_to_le64(STRTAB_STE_1_MEV);
> +}
> +
> +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_nested_cdtable_ste(&s1_ste,
> +					      STRTAB_STE_1_S1DSS_BYPASS,
> +					      fake_cdtab_dma_addr,
> +					      ARM_SMMU_MASTER_TEST_ATS);
> +	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));
> +}
> +
> +static void
> +arm_smmu_v3_write_ste_test_nested_s1bypass_to_s1dssbypass(struct kunit *test)
> +{
> +	struct arm_smmu_ste s1_ste;
> +	struct arm_smmu_ste s2_ste;
> +
> +	arm_smmu_test_make_nested_cdtable_ste(&s1_ste,
> +					      STRTAB_STE_1_S1DSS_BYPASS,
> +					      fake_cdtab_dma_addr,
> +					      ARM_SMMU_MASTER_TEST_ATS);
> +	arm_smmu_test_make_s2_ste(&s2_ste, 0);
> +	arm_smmu_v3_test_ste_expect_hitless_transition(test, &s2_ste, &s1_ste,
> +						       NUM_EXPECTED_SYNCS(2));

It would be better to add comments explaining why the number of syncs differs
between the reverse transitions.

> +}
> +
>   static void arm_smmu_v3_write_cd_test_sva_clear(struct kunit *test)
>   {
>   	struct arm_smmu_cd cd = {};
> @@ -601,6 +660,8 @@ static struct kunit_case arm_smmu_v3_test_cases[] = {
>   	KUNIT_CASE(arm_smmu_v3_write_cd_test_s1_change_asid),
>   	KUNIT_CASE(arm_smmu_v3_write_ste_test_s1_to_s2_stall),
>   	KUNIT_CASE(arm_smmu_v3_write_ste_test_s2_to_s1_stall),
> +	KUNIT_CASE(arm_smmu_v3_write_ste_test_nested_s1dssbypass_to_s1bypass),
> +	KUNIT_CASE(arm_smmu_v3_write_ste_test_nested_s1bypass_to_s1dssbypass),
>   	KUNIT_CASE(arm_smmu_v3_write_cd_test_sva_clear),
>   	KUNIT_CASE(arm_smmu_v3_write_cd_test_sva_release),
>   	{},

Reviewed-by: Shuai Xue <xueshuai@linux.alibaba.com>

Thanks.
Shuai