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authorLu Baolu <baolu.lu@linux.intel.com>2021-02-25 14:14:54 +0800
committerJoerg Roedel <jroedel@suse.de>2021-03-04 13:22:28 +0100
commit82c3cefb9f1652e7470f442ff96c613e8c8ed8f4 (patch)
tree740897d9eecf2e4da4e672e17137bc2df3caf163
parent765a9d1d02b2f5996b05f5f65faa8a634adbe763 (diff)
downloadlinux-82c3cefb9f1652e7470f442ff96c613e8c8ed8f4.tar.bz2
iommu: Don't use lazy flush for untrusted device
The lazy IOTLB flushing setup leaves a time window, in which the device can still access some system memory, which has already been unmapped by the device driver. It's not suitable for untrusted devices. A malicious device might use this to attack the system by obtaining data that it shouldn't obtain. Fixes: c588072bba6b5 ("iommu/vt-d: Convert intel iommu driver to the iommu ops") Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20210225061454.2864009-1-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
-rw-r--r--drivers/iommu/dma-iommu.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index f659395e7959..65234e383d6b 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -311,6 +311,11 @@ static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad)
domain->ops->flush_iotlb_all(domain);
}
+static bool dev_is_untrusted(struct device *dev)
+{
+ return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
+}
+
/**
* iommu_dma_init_domain - Initialise a DMA mapping domain
* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
@@ -365,8 +370,9 @@ 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 && !iommu_domain_get_attr(domain,
- DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) && attr) {
+ if (!cookie->fq_domain && (!dev || !dev_is_untrusted(dev)) &&
+ !iommu_domain_get_attr(domain, DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) &&
+ attr) {
if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
iommu_dma_entry_dtor))
pr_warn("iova flush queue initialization failed\n");
@@ -508,11 +514,6 @@ static void __iommu_dma_unmap_swiotlb(struct device *dev, dma_addr_t dma_addr,
iova_align(iovad, size), dir, attrs);
}
-static bool dev_is_untrusted(struct device *dev)
-{
- return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
-}
-
static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
size_t size, int prot, u64 dma_mask)
{