From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
iommu@lists.linux-foundation.org, joro@8bytes.org,
bhelgaas@google.com
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
Joerg Roedel <jroedel@suse.de>,
ashok.raj@intel.com, will@kernel.org, hch@infradead.org,
alex.williamson@redhat.com, robin.murphy@arm.com,
dwmw2@infradead.org
Subject: [PATCH v2 2/4] iommu/amd: Use pci_ats_supported()
Date: Wed, 20 May 2020 17:22:01 +0200 [thread overview]
Message-ID: <20200520152201.3309416-3-jean-philippe@linaro.org> (raw)
In-Reply-To: <20200520152201.3309416-1-jean-philippe@linaro.org>
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.
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
drivers/iommu/amd_iommu.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 1dc3718560d0..8b7a9e811d33 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -313,16 +313,15 @@ 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;
@@ -3150,11 +3149,8 @@ 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)
--
2.26.2
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2020-05-20 15:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 15:21 [PATCH v2 0/4] PCI, iommu: Factor 'untrusted' check for ATS enablement Jean-Philippe Brucker
2020-05-20 15:22 ` [PATCH v2 1/4] PCI/ATS: Only enable ATS for trusted devices Jean-Philippe Brucker
2020-05-20 15:22 ` Jean-Philippe Brucker [this message]
2020-05-20 15:22 ` [PATCH v2 3/4] iommu/arm-smmu-v3: Use pci_ats_supported() Jean-Philippe Brucker
2020-05-21 10:29 ` Will Deacon
2020-05-20 15:22 ` [PATCH v2 4/4] iommu/vt-d: " Jean-Philippe Brucker
2020-05-27 9:38 ` [PATCH v2 0/4] PCI, iommu: Factor 'untrusted' check for ATS enablement Jean-Philippe Brucker
2020-05-27 12:36 ` Joerg Roedel
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