5.0-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit d8b8591054575f33237556c32762d54e30774d28 ]
Commit fb58fdcd295b9 ("iommu/vt-d: Do not enable ATS for untrusted devices") disables ATS support on the devices which have been marked as untrusted. Unfortunately this is not enough to fix the DMA attack vulnerabiltiies because IOMMU driver allows translated requests as long as a device advertises the ATS capability. Hence a malicious peripheral device could use this to bypass IOMMU.
This disables the ATS support on untrusted devices by clearing the internal per-device ATS mark. As the result, IOMMU driver will block any translated requests from any device marked as untrusted.
Cc: Jacob Pan jacob.jun.pan@linux.intel.com Cc: Mika Westerberg mika.westerberg@linux.intel.com Suggested-by: Kevin Tian kevin.tian@intel.com Suggested-by: Ashok Raj ashok.raj@intel.com Fixes: fb58fdcd295b9 ("iommu/vt-d: Do not enable ATS for untrusted devices") Signed-off-by: Lu Baolu baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 78188bf7e90d..dbd6824dfffa 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2485,7 +2485,8 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, if (dev && dev_is_pci(dev)) { struct pci_dev *pdev = to_pci_dev(info->dev);
- if (!pci_ats_disabled() && + if (!pdev->untrusted && + !pci_ats_disabled() && ecap_dev_iotlb_support(iommu->ecap) && pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS) && dmar_find_matched_atsr_unit(pdev))