kernel/linux.git/include/linux/pci-ats.h, branch v6.19.11

iommufd: Extend IOMMU_GET_HW_INFO to report PASID capability

2025-03-28T13:07:23+00:00

PASID usage requires PASID support in both device and IOMMU. Since the iommu drivers always enable the PASID capability for the device if it is supported, this extends the IOMMU_GET_HW_INFO to report the PASID capability to userspace. Also, enhances the selftest accordingly. Link: https://patch.msgid.link/r/20250321180143.8468-5-yi.l.liu@intel.com Cc: Bjorn Helgaas Reviewed-by: Kevin Tian Reviewed-by: Jason Gunthorpe Tested-by: Zhangfei Gao #aarch64 platform Tested-by: Nicolin Chen Signed-off-by: Yi Liu Signed-off-by: Jason Gunthorpe

iommu: Allow ATS to work on VFs when the PF uses IDENTITY

2024-08-30T12:29:30+00:00

PCI ATS has a global Smallest Translation Unit field that is located in the PF but shared by all of the VFs. The expectation is that the STU will be set to the root port's global STU capability which is driven by the IO page table configuration of the iommu HW. Today it becomes set when the iommu driver first enables ATS. Thus, to enable ATS on the VF, the PF must have already had the correct STU programmed, even if ATS is off on the PF. Unfortunately the PF only programs the STU when the PF enables ATS. The iommu drivers tend to leave ATS disabled when IDENTITY translation is being used. Thus we can get into a state where the PF is setup to use IDENTITY with the DMA API while the VF would like to use VFIO with a PAGING domain and have ATS turned on. This fails because the PF never loaded a PAGING domain and so it never setup the STU, and the VF can't do it. The simplest solution is to have the iommu driver set the ATS STU when it probes the device. This way the ATS STU is loaded immediately at boot time to all PFs and there is no issue when a VF comes to use it. Add a new call pci_prepare_ats() which should be called by iommu drivers in their probe_device() op for every PCI device if the iommu driver supports ATS. This will setup the STU based on whatever page size capability the iommu HW has. Signed-off-by: Jason Gunthorpe Acked-by: Bjorn Helgaas Reviewed-by: Kevin Tian Reviewed-by: Lu Baolu Link: https://lore.kernel.org/r/0-v1-0fb4d2ab6770+7e706-ats_vf_jgg@nvidia.com Signed-off-by: Joerg Roedel

PCI/ATS: Add pci_pri_supported() to check device or associated PF

2020-07-24T14:50:41+00:00

For SR-IOV, the PF PRI is shared between the PF and any associated VFs, and the PRI Capability is allowed for PFs but not for VFs. Searching for the PRI Capability on a VF always fails, even if its associated PF supports PRI. Add pci_pri_supported() to check whether device or its associated PF supports PRI. [bhelgaas: commit log, avoid "!!"] Fixes: b16d0cb9e2fc ("iommu/vt-d: Always enable PASID/PRI PCI capabilities before ATS") Link: https://lore.kernel.org/r/1595543849-19692-1-git-send-email-ashok.raj@intel.com Signed-off-by: Ashok Raj Signed-off-by: Bjorn Helgaas Reviewed-by: Lu Baolu Acked-by: Joerg Roedel Cc: stable@vger.kernel.org # v4.4+

PCI/ATS: Only enable ATS for trusted devices

2020-05-27T12:35:41+00:00

Add pci_ats_supported(), which checks whether a device has an ATS capability, and whether it is trusted. 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. PCIe ATS is one such weaknesses since it allows endpoints to cache IOMMU translations and emit transactions with 'Translated' Address Type (10b) that partially bypass the IOMMU translation. The SMMUv3 and VT-d IOMMU drivers already disallow ATS and transactions with 'Translated' Address Type for untrusted devices. Add the check to pci_enable_ats() to let other drivers (AMD IOMMU for now) benefit from it. By checking ats_cap, the pci_ats_supported() helper also returns whether ATS was globally disabled with pci=noats, and could later include more things, for example whether the whole PCIe hierarchy down to the endpoint supports ATS. Signed-off-by: Jean-Philippe Brucker Reviewed-by: Joerg Roedel Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20200520152201.3309416-2-jean-philippe@linaro.org Signed-off-by: Joerg Roedel

PCI/ATS: Add PASID stubs

2020-01-15T16:30:28+00:00

The SMMUv3 driver, which may be built without CONFIG_PCI, will soon gain PASID support. Partially revert commit c6e9aefbf9db ("PCI/ATS: Remove unused PRI and PASID stubs") to re-introduce the PASID stubs, and avoid adding more #ifdefs to the SMMU driver. Acked-by: Bjorn Helgaas Reviewed-by: Eric Auger Reviewed-by: Jonathan Cameron Signed-off-by: Jean-Philippe Brucker Signed-off-by: Will Deacon

PCI/ATS: Make pci_restore_pri_state(), pci_restore_pasid_state() private

2019-10-15T21:39:11+00:00

These interfaces: void pci_restore_pri_state(struct pci_dev *pdev); void pci_restore_pasid_state(struct pci_dev *pdev); are only used in drivers/pci and do not need to be seen by the rest of the kernel. Most them to drivers/pci/pci.h so they're private to the PCI subsystem. Signed-off-by: Bjorn Helgaas Reviewed-by: Joerg Roedel

PCI/ATS: Remove unused PRI and PASID stubs

2019-10-15T21:39:11+00:00

The following functions are only used by amd_iommu.c and intel-iommu.c (when CONFIG_INTEL_IOMMU_SVM is enabled). CONFIG_PCI_PRI and CONFIG_PCI_PASID are always defined in those cases, so there's no need for the stubs. pci_enable_pri() pci_disable_pri() pci_reset_pri() pci_prg_resp_pasid_required() pci_enable_pasid() pci_disable_pasid() Remove the unused stubs. Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: Joerg Roedel

PCI/ATS: Consolidate ATS declarations in linux/pci-ats.h

2019-10-15T21:39:11+00:00

Move ATS function prototypes from include/linux/pci.h to include/linux/pci-ats.h as the ATS, PRI, and PASID interfaces are related and are used only by the IOMMU drivers. This effectively reverts ff9bee895c4d ("PCI: Move ATS declarations to linux/pci.h so they're all together"). Also, remove surplus forward declaration of struct pci_ats from include/linux/pci.h, as it is no longer needed, since struct pci_ats was embedded directly into struct pci_dev by d544d75ac96a ("PCI: Embed ATS info directly into struct pci_dev"). No functional changes intended. Link: https://lore.kernel.org/r/20190914213032.22314-1-kw@linux.com Signed-off-by: Krzysztof Wilczynski Signed-off-by: Bjorn Helgaas

PCI/ATS: Move pci_prg_resp_pasid_required() to CONFIG_PCI_PRI

2019-10-15T21:38:33+00:00

pci_prg_resp_pasid_required() returns the value of the "PRG Response PASID Required" bit from the PRI capability, but the interface was previously defined under #ifdef CONFIG_PCI_PASID. Move it from CONFIG_PCI_PASID to CONFIG_PCI_PRI so it's with the other PRI-related things. Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: Joerg Roedel

PCI/ATS: Add inline to pci_prg_resp_pasid_required()

2019-02-28T10:09:29+00:00

Fix unused function warning when compiled with CONFIG_PCI_PASID disabled. Fixes: e5567f5f6762 ("PCI/ATS: Add pci_prg_resp_pasid_required() interface.") Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Joerg Roedel