Messages in this thread | | | Subject | Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type | From | Lu Baolu <> | Date | Sat, 24 Jul 2021 13:29:34 +0800 |
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Hi Robin,
On 2021/7/22 2:20, Robin Murphy wrote: > Eliminate the iommu_get_dma_strict() indirection and pipe the > information through the domain type from the beginning. Besides > the flow simplification this also has several nice side-effects: > > - Automatically implies strict mode for untrusted devices by > virtue of their IOMMU_DOMAIN_DMA override. > - Ensures that we only ends up using flush queues for drivers > which are aware of them and can actually benefit.
Is this expressed by vendor iommu driver has ops->flush_iotlb_all?
> - Allows us to handle flush queue init failure by falling back > to strict mode instead of leaving it to possibly blow up later. > > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 +- > drivers/iommu/arm/arm-smmu/arm-smmu.c | 2 +- > drivers/iommu/dma-iommu.c | 10 ++++++---- > drivers/iommu/iommu.c | 14 ++++---------- > include/linux/iommu.h | 1 - > 5 files changed, 12 insertions(+), 17 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > index fa41026d272e..260b560d0075 100644 > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c > @@ -2175,7 +2175,7 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain, > .iommu_dev = smmu->dev, > }; > > - if (!iommu_get_dma_strict(domain)) > + if (domain->type == IOMMU_DOMAIN_DMA_FQ) > pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; > > pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain); > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c > index dbc14c265b15..2c717f3be056 100644 > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c > @@ -765,7 +765,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, > .iommu_dev = smmu->dev, > }; > > - if (!iommu_get_dma_strict(domain)) > + if (domain->type == IOMMU_DOMAIN_DMA_FQ) > pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT; > > if (smmu->impl && smmu->impl->init_context) { > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index b1af1ff324c5..a114a7ad88ec 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -363,13 +363,15 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, > > init_iova_domain(iovad, 1UL << order, base_pfn); > > - if (!cookie->fq_domain && !dev_is_untrusted(dev) && > - domain->ops->flush_iotlb_all && !iommu_get_dma_strict(domain)) { > + if (domain->type == IOMMU_DOMAIN_DMA_FQ && !cookie->fq_domain && > + domain->ops->flush_iotlb_all) { > if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, > - iommu_dma_entry_dtor)) > + iommu_dma_entry_dtor)) { > pr_warn("iova flush queue initialization failed\n"); > - else > + domain->type = IOMMU_DOMAIN_DMA; > + } else { > cookie->fq_domain = domain; > + } > } > > return iova_reserve_iommu_regions(dev, domain); > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 8333c334891e..d7eaacae0944 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -135,6 +135,9 @@ static int __init iommu_subsys_init(void) > } > } > > + if (!iommu_default_passthrough() && !iommu_dma_strict) > + iommu_def_domain_type = IOMMU_DOMAIN_DMA_FQ; > + > pr_info("Default domain type: %s %s\n", > iommu_domain_type_str(iommu_def_domain_type), > (iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ? > @@ -352,15 +355,6 @@ void iommu_set_dma_strict(bool strict) > iommu_dma_strict = strict; > } > > -bool iommu_get_dma_strict(struct iommu_domain *domain) > -{ > - /* only allow lazy flushing for DMA domains */ > - if (domain->type == IOMMU_DOMAIN_DMA) > - return iommu_dma_strict; > - return true; > -} > -EXPORT_SYMBOL_GPL(iommu_get_dma_strict); > - > static ssize_t iommu_group_attr_show(struct kobject *kobj, > struct attribute *__attr, char *buf) > { > @@ -764,7 +758,7 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group, > unsigned long pg_size; > int ret = 0; > > - if (!domain || domain->type != IOMMU_DOMAIN_DMA) > + if (!domain || !(domain->type & __IOMMU_DOMAIN_DMA_API))
Nit: probably move above change to patch 14?
> return 0; > > BUG_ON(!domain->pgsize_bitmap); > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 56519110d43f..557c4c12e2cf 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -484,7 +484,6 @@ int iommu_set_pgtable_quirks(struct iommu_domain *domain, > unsigned long quirks); > > void iommu_set_dma_strict(bool val); > -bool iommu_get_dma_strict(struct iommu_domain *domain); > > extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev, > unsigned long iova, int flags); >
Best regards, baolu
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