Messages in this thread |  | | From | Lu Baolu <> | Subject | Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type | Date | Mon, 26 Jul 2021 20:29:58 +0800 |
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On 2021/7/26 16:27, Robin Murphy wrote: > 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) {
Perhaps we can remove the ops->flush_iotlb_all check with the assumption that any vendor iommu driver with DMA_FQ domain support should always provides this callback?
Best regards, baolu
>>> 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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