From: Lu Baolu Date: Fri, 1 Mar 2019 03:23:10 +0000 (+0800) Subject: iommu/vt-d: Disable ATS support on untrusted devices X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d8b8591054575f33237556c32762d54e30774d28;p=linux.git iommu/vt-d: Disable ATS support on untrusted devices 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 Cc: Mika Westerberg Suggested-by: Kevin Tian Suggested-by: Ashok Raj Fixes: fb58fdcd295b9 ("iommu/vt-d: Do not enable ATS for untrusted devices") Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index c30b73d41bf22..64ce780336a89 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2484,7 +2484,8 @@ 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))