From 98b2fffb5e274d73e47d495da2caf213cfa28fc8 Mon Sep 17 00:00:00 2001 From: Lu Baolu Date: Sat, 25 May 2019 13:41:30 +0800 Subject: [PATCH] iommu/vt-d: Handle 32bit device with identity default domain The iommu driver doesn't know whether the bit width of a PCI device is sufficient for access to the whole system memory. Hence, the driver checks this when the driver calls into the dma APIs. If a device is using an identity domain, but the bit width is less than the system requirement, we need to use a dma domain instead. This also applies after we delegated the domain life cycle management to the upper layer. Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel --- drivers/iommu/intel-iommu.c | 55 +++++++++++++++---------------------- 1 file changed, 22 insertions(+), 33 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 5dae957531f3..87f9f2237238 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2984,25 +2984,6 @@ static int device_def_domain_type(struct device *dev, int startup) return IOMMU_DOMAIN_DMA; } - /* - * At boot time, we don't yet know if devices will be 64-bit capable. - * Assume that they will — if they turn out not to be, then we can - * take them out of the 1:1 domain later. - */ - if (!startup) { - /* - * If the device's dma_mask is less than the system's memory - * size then this is not a candidate for identity mapping. - */ - u64 dma_mask = *dev->dma_mask; - - if (dev->coherent_dma_mask && - dev->coherent_dma_mask < dma_mask) - dma_mask = dev->coherent_dma_mask; - - return dma_mask >= dma_get_required_mask(dev); - } - return (iommu_identity_mapping & IDENTMAP_ALL) ? IOMMU_DOMAIN_IDENTITY : 0; } @@ -3614,14 +3595,19 @@ struct dmar_domain *get_valid_domain_for_dev(struct device *dev) /* Check if the dev needs to go through non-identity map and unmap process.*/ static bool iommu_need_mapping(struct device *dev) { - int found; + int ret; if (iommu_dummy(dev)) return false; - found = identity_mapping(dev); - if (found) { - if (iommu_should_identity_map(dev, 0)) + ret = identity_mapping(dev); + if (ret) { + u64 dma_mask = *dev->dma_mask; + + if (dev->coherent_dma_mask && dev->coherent_dma_mask < dma_mask) + dma_mask = dev->coherent_dma_mask; + + if (dma_mask >= dma_get_required_mask(dev)) return false; /* @@ -3629,17 +3615,20 @@ static bool iommu_need_mapping(struct device *dev) * non-identity mapping. */ dmar_remove_one_dev_info(dev); - dev_info(dev, "32bit DMA uses non-identity mapping\n"); - } else { - /* - * In case of a detached 64 bit DMA device from vm, the device - * is put into si_domain for identity mapping. - */ - if (iommu_should_identity_map(dev, 0) && - !domain_add_dev_info(si_domain, dev)) { - dev_info(dev, "64bit DMA uses identity mapping\n"); - return false; + ret = iommu_request_dma_domain_for_dev(dev); + if (ret) { + struct iommu_domain *domain; + struct dmar_domain *dmar_domain; + + domain = iommu_get_domain_for_dev(dev); + if (domain) { + dmar_domain = to_dmar_domain(domain); + dmar_domain->flags |= DOMAIN_FLAG_LOSE_CHILDREN; + } + get_valid_domain_for_dev(dev); } + + dev_info(dev, "32bit DMA uses non-identity mapping\n"); } return true;