Re: [PATCHv9 3/8] iommu/arm-smmu: Move non-strict mode to use io_pgtable_domain_attr
From: Will Deacon <will@kernel.org>
Date: 2020-11-24 21:39:46
Also in:
dri-devel, linux-arm-msm, linux-iommu, lkml
On Mon, Nov 23, 2020 at 10:35:56PM +0530, Sai Prakash Ranjan wrote:
quoted hunk
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 <redacted> --- 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.
quoted hunk
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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel