On Mon, Nov 23, 2020 at 10:35:56PM +0530, Sai Prakash Ranjan wrote:
> Now that we have a struct io_pgtable_domain_attr with quirks,
> use that for non_strict mode as well thereby removing the need
> for more members of arm_smmu_domain in the future.
>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> ---
> drivers/iommu/arm/arm-smmu/arm-smmu.c | 8 +++-----
> drivers/iommu/arm/arm-smmu/arm-smmu.h | 1 -
> 2 files changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index 4b9b10fe50ed..f56f266ebdf7 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -786,9 +786,6 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
> goto out_clear_smmu;
> }
>
> - if (smmu_domain->non_strict)
> - pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
> -
> if (smmu_domain->pgtbl_cfg.quirks)
> pgtbl_cfg.quirks |= smmu_domain->pgtbl_cfg.quirks;
>
> @@ -1527,7 +1524,8 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> case IOMMU_DOMAIN_DMA:
> switch (attr) {
> case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
> - *(int *)data = smmu_domain->non_strict;
> + if (smmu_domain->pgtbl_cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT)
> + *(int *)data = smmu_domain->pgtbl_cfg.quirks;
I still don't think this is right :(
We need to set *data to 1 or 0 depending on whether or not the non-strict
quirk is set, i.e:
bool non_strict = smmu_domain->pgtbl_cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT;
*(int *)data = non_strict;
Your code above leaves *data uninitialised if non_strict is not set.
> return 0;
> default:
> return -ENODEV;
> @@ -1578,7 +1576,7 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
> case IOMMU_DOMAIN_DMA:
> switch (attr) {
> case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
> - smmu_domain->non_strict = *(int *)data;
> + smmu_domain->pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
And this is broken because if *data is 0, then you _set_ the quirk, which is
the opposite of what we should be doing.
In other words, although the implementation has changed, the semantics have
not.
Will
