diff options
| -rw-r--r-- | drivers/iommu/dma-iommu.c | 26 | ||||
| -rw-r--r-- | drivers/iommu/dma-iommu.h | 8 | ||||
| -rw-r--r-- | drivers/iommu/iommu.c | 3 | ||||
| -rw-r--r-- | include/linux/iommu.h | 2 |
4 files changed, 33 insertions, 6 deletions
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index e57724163835..4b1a88f514c9 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -660,7 +660,7 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain, { struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; - unsigned long shift, iova_len, iova = 0; + unsigned long shift, iova_len, iova; if (cookie->type == IOMMU_DMA_MSI_COOKIE) { cookie->msi_iova += size; @@ -675,15 +675,29 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain, if (domain->geometry.force_aperture) dma_limit = min(dma_limit, (u64)domain->geometry.aperture_end); - /* Try to get PCI devices a SAC address */ - if (dma_limit > DMA_BIT_MASK(32) && !iommu_dma_forcedac && dev_is_pci(dev)) + /* + * Try to use all the 32-bit PCI addresses first. The original SAC vs. + * DAC reasoning loses relevance with PCIe, but enough hardware and + * firmware bugs are still lurking out there that it's safest not to + * venture into the 64-bit space until necessary. + * + * If your device goes wrong after seeing the notice then likely either + * its driver is not setting DMA masks accurately, the hardware has + * some inherent bug in handling >32-bit addresses, or not all the + * expected address bits are wired up between the device and the IOMMU. + */ + if (dma_limit > DMA_BIT_MASK(32) && dev->iommu->pci_32bit_workaround) { iova = alloc_iova_fast(iovad, iova_len, DMA_BIT_MASK(32) >> shift, false); + if (iova) + goto done; - if (!iova) - iova = alloc_iova_fast(iovad, iova_len, dma_limit >> shift, - true); + dev->iommu->pci_32bit_workaround = false; + dev_notice(dev, "Using %d-bit DMA addresses\n", bits_per(dma_limit)); + } + iova = alloc_iova_fast(iovad, iova_len, dma_limit >> shift, true); +done: return (dma_addr_t)iova << shift; } diff --git a/drivers/iommu/dma-iommu.h b/drivers/iommu/dma-iommu.h index 942790009292..c829f1f82a99 100644 --- a/drivers/iommu/dma-iommu.h +++ b/drivers/iommu/dma-iommu.h @@ -17,6 +17,10 @@ int iommu_dma_init_fq(struct iommu_domain *domain); void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list); extern bool iommu_dma_forcedac; +static inline void iommu_dma_set_pci_32bit_workaround(struct device *dev) +{ + dev->iommu->pci_32bit_workaround = !iommu_dma_forcedac; +} #else /* CONFIG_IOMMU_DMA */ @@ -38,5 +42,9 @@ static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_he { } +static inline void iommu_dma_set_pci_32bit_workaround(struct device *dev) +{ +} + #endif /* CONFIG_IOMMU_DMA */ #endif /* __DMA_IOMMU_H */ diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 42377f49ab87..e67f6562da73 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -499,6 +499,9 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list mutex_unlock(&group->mutex); mutex_unlock(&iommu_probe_device_lock); + if (dev_is_pci(dev)) + iommu_dma_set_pci_32bit_workaround(dev); + return 0; err_remove_gdev: diff --git a/include/linux/iommu.h b/include/linux/iommu.h index d31642596675..b1dcb1b9b170 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -409,6 +409,7 @@ struct iommu_fault_param { * @priv: IOMMU Driver private data * @max_pasids: number of PASIDs this device can consume * @attach_deferred: the dma domain attachment is deferred + * @pci_32bit_workaround: Limit DMA allocations to 32-bit IOVAs * * TODO: migrate other per device data pointers under iommu_dev_data, e.g. * struct iommu_group *iommu_group; @@ -422,6 +423,7 @@ struct dev_iommu { void *priv; u32 max_pasids; u32 attach_deferred:1; + u32 pci_32bit_workaround:1; }; int iommu_device_register(struct iommu_device *iommu, |