diff options
| author | Gil Kupfer <gilkup@gmail.com> | 2018-05-10 17:56:02 -0500 |
|---|---|---|
| committer | Bjorn Helgaas <helgaas@kernel.org> | 2018-05-10 17:56:02 -0500 |
| commit | cef74409ea79b0a37af6889e7abf7a2a9c47979b (patch) | |
| tree | 243ec22ccce2f44cf17e288ad0415691ad43f4e6 /drivers/iommu | |
| parent | f154a718e6cc0d834f5ac4dc4c3b174e65f3659e (diff) | |
PCI: Add "pci=noats" boot parameter
Adds a "pci=noats" boot parameter. When supplied, all ATS related
functions fail immediately and the IOMMU is configured to not use
device-IOTLB.
Any function that checks for ATS capabilities directly against the devices
should also check this flag. Currently, such functions exist only in IOMMU
drivers, and they are covered by this patch.
The motivation behind this patch is the existence of malicious devices.
Lots of research has been done about how to use the IOMMU as protection
from such devices. When ATS is supported, any I/O device can access any
physical address by faking device-IOTLB entries. Adding the ability to
ignore these entries lets sysadmins enhance system security.
Signed-off-by: Gil Kupfer <gilkup@cs.technion.ac.il>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/amd_iommu.c | 11 | ||||
| -rw-r--r-- | drivers/iommu/intel-iommu.c | 3 |
2 files changed, 10 insertions, 4 deletions
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 2a99f0f14795..56da1c6121d3 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -355,6 +355,9 @@ static bool pci_iommuv2_capable(struct pci_dev *pdev) }; int i, pos; + if (pci_ats_disabled()) + return false; + for (i = 0; i < 3; ++i) { pos = pci_find_ext_capability(pdev, caps[i]); if (pos == 0) @@ -3524,9 +3527,11 @@ int amd_iommu_device_info(struct pci_dev *pdev, memset(info, 0, sizeof(*info)); - pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS); - if (pos) - info->flags |= AMD_IOMMU_DEVICE_FLAG_ATS_SUP; + if (!pci_ats_disabled()) { + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS); + if (pos) + info->flags |= AMD_IOMMU_DEVICE_FLAG_ATS_SUP; + } pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI); if (pos) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 749d8f235346..772b404a6604 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -2459,7 +2459,8 @@ 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 (ecap_dev_iotlb_support(iommu->ecap) && + if (!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)) info->ats_supported = 1; |