Commit 2e34673b authored Jan 29, 2020 by Kuppuswamy Sathyanarayanan Committed by Bjorn Helgaas Feb 05, 2020

PCI/ATS: Use PF PASID for VFs

Per PCIe r5.0, sec 9.3.7.14, if a PF implements the PASID Capability, the
PF PASID configuration is shared by its VFs, and VFs must not implement
their own PASID Capability. But commit 751035b8 ("PCI/ATS: Cache PASID
Capability offset") changed pci_max_pasids() and pci_pasid_features() to
use the PASID Capability of the VF device instead of the associated PF
device. This leads to IOMMU bind failures when pci_max_pasids() and
pci_pasid_features() are called for VFs.

In pci_max_pasids() and pci_pasid_features(), always use the PF PASID
Capability.

Fixes: 751035b8 ("PCI/ATS: Cache PASID Capability offset")
Link: https://lore.kernel.org/r/fe891f9755cb18349389609e7fed9940fc5b081a.1580325170.git.sathyanarayanan.kuppuswamy@linux.intel.com

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org # v5.5+

parent b9303bb1

drivers/pci/ats.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -424,11 +424,12 @@ void pci_restore_pasid_state(struct pci_dev *pdev)
		int pci_pasid_features(struct pci_dev *pdev)
		{
		u16 supported;
		int pasid = pdev->pasid_cap;
		int pasid;

		if (pdev->is_virtfn)
		pdev = pci_physfn(pdev);

		pasid = pdev->pasid_cap;
		if (!pasid)
		return -EINVAL;

		@@ -451,11 +452,12 @@ int pci_pasid_features(struct pci_dev *pdev)
		int pci_max_pasids(struct pci_dev *pdev)
		{
		u16 supported;
		int pasid = pdev->pasid_cap;
		int pasid;

		if (pdev->is_virtfn)
		pdev = pci_physfn(pdev);

		pasid = pdev->pasid_cap;
		if (!pasid)
		return -EINVAL;