Messages in this thread |  | | Subject | Re: [PATCH v4 4/5] iommu/arm-smmu-v3: add support for non-strict mode | From | Robin Murphy <> | Date | Thu, 9 Aug 2018 12:06:29 +0100 |
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On 06/08/18 13:27, Zhen Lei wrote: > Dynamically choose strict or non-strict mode for page table config based > on the iommu domain type. > > Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> > --- > 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 > >
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