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iommu/amd: Use pci_ats_supported() 

The pci_ats_supported() function checks if a device supports ATS and is
allowed to use it. In addition to checking that the device has an ATS
capability and that the global pci=noats is not set
(pci_ats_disabled()), it also checks if a device is untrusted.

A device is untrusted if it is plugged into an external-facing port such
as Thunderbolt and could be spoofing an existing device to exploit
weaknesses in the IOMMU configuration. By calling pci_ats_supported() we
keep DTE[I]=0 for untrusted devices and abort transactions with
Pretranslated Addresses.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20200520152201.3309416-3-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Jean-Philippe Brucker 2020-05-20 17:22:01 +02:00 committed by Joerg Roedel
parent 521376741b
commit 7a441b2110
1 changed files with 4 additions and 8 deletions
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12
drivers/iommu/amd_iommu.c
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@ -291,16 +291,15 @@ static struct iommu_group *acpihid_device_group(struct device *dev)
static bool pci_iommuv2_capable(struct pci_dev *pdev)
{
static const int caps[] = {
PCI_EXT_CAP_ID_ATS,
PCI_EXT_CAP_ID_PRI,
PCI_EXT_CAP_ID_PASID,
};
int i, pos;
if (pci_ats_disabled())
if (!pci_ats_supported(pdev))
return false;
for (i = 0; i < 3; ++i) {
for (i = 0; i < 2; ++i) {
pos = pci_find_ext_capability(pdev, caps[i]);
if (pos == 0)
return false;
@ -3028,11 +3027,8 @@ int amd_iommu_device_info(struct pci_dev *pdev,
memset(info, 0, sizeof(*info));
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;
}
if (pci_ats_supported(pdev))
info->flags |= AMD_IOMMU_DEVICE_FLAG_ATS_SUP;
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
if (pos)