Messages in this thread |  | | Subject | Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type | From | Robin Murphy <> | Date | Mon, 26 Jul 2021 09:27:01 +0100 |
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On 2021-07-24 06:29, Lu Baolu wrote: > 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?
No, it's literally whether ->domain_alloc accepts the DMA_DOMAIN_FQ type or not.
>> - 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?
Indeed I'm not sure why this one ended up here, good catch!
Thanks, Robin.
>> 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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