Re: [PATCH v1 1/1] PCI/ATS: For VF PCIe device use PF PASID Capability

From: Bjorn Helgaas
Date: Wed Feb 05 2020 - 13:11:36 EST


On Wed, Jan 29, 2020 at 11:14:00AM -0800, sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
>
> 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. VFs must not implement
> their own PASID Capability. But, commit 751035b8dc06 ("PCI/ATS: Cache
> PASID Capability offset") when adding support for PASID Capability
> offset caching, modified the pci_max_pasids() and pci_pasid_features()
> APIs to use PASID Capability offset of VF device instead of using
> PASID Capability offset of associated PF device. This change leads to
> IOMMU bind failures when pci_max_pasids() and pci_pasid_features()
> functions are invoked by PCIe VF devices.
>
> So modify pci_max_pasids() and pci_pasid_features() functions to use
> correct PASID Capability offset.
>
> Fixes: 751035b8dc06 ("PCI/ATS: Cache PASID Capability offset")
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

Applied to for-linus for v5.6, thanks! I also added a stable tag
since 751035b8dc06 appeared in v5.5.

> ---
> drivers/pci/ats.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
> index 982b46f0a54d..b6f064c885c3 100644
> --- a/drivers/pci/ats.c
> +++ b/drivers/pci/ats.c
> @@ -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;
>
> --
> 2.21.0
>