[PATCH v4 4/5] iommu/arm-smmu-v3: add support for non-strict mode
From: robin.murphy@arm.com (Robin Murphy)
Date: 2018-08-09 11:06:35
Also in:
linux-iommu, lkml
On 06/08/18 13:27, Zhen Lei wrote:
quoted hunk ↗ jump to hunk
Dynamically choose strict or non-strict mode for page table config based on the iommu domain type. Signed-off-by: Zhen Lei <redacted> --- drivers/iommu/arm-smmu-v3.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 2f1304b..904bc1e 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c@@ -1622,6 +1622,11 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain) if (smmu->features & ARM_SMMU_FEAT_COHERENCY) pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA; + if (domain->type == IOMMU_DOMAIN_DMA) { + domain->non_strict = 1; + pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; + } + pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain); if (!pgtbl_ops) return -ENOMEM;@@ -1782,7 +1787,7 @@ static void arm_smmu_iotlb_sync(struct iommu_domain *domain) { struct arm_smmu_device *smmu = to_smmu_domain(domain)->smmu; - if (smmu) + if (smmu && !domain->non_strict)
That doesn't smell right - even in non-strict domains we still need stuff like walk cache invalidations for non-leaf unmaps to be synchronous, so we can't just ignore all sync operations at the driver level. I think the right thing to do to elide the "normal" sync on unmap is to first convert __iommu_dma_unmap to use iommu_unmap_fast()/iommu_tlb_sync(), then make it not issue that sync at all for non-strict domains. Robin.
__arm_smmu_tlb_sync(smmu); } -- 1.8.3