Re: [PATCH] iommufd: modify iommufd_fault_iopf_enable limitation

[Zhangfei Gao]

On Mon, 28 Oct 2024 at 11:32, Zhangfei Gao <zhangfei.gao@xxxxxxxxxx> wrote:
>
> iommufd_fault_iopf_enable has limitation to PRI on PCI/SRIOV VFs
> because the PRI might be a shared resource and current iommu
> subsystem is not ready to support enabling/disabling PRI on a VF
> without any impact on others.
>
> However, we have devices that appear as PCI but are actually on the
> AMBA bus. These fake PCI devices have PASID capability, support
> stall as well as SRIOV, so remove the limitation for these devices.
>
> Signed-off-by: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> ---
>  drivers/iommu/iommufd/fault.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/iommufd/fault.c b/drivers/iommu/iommufd/fault.c
> index bca956d496bd..8b3e34250dae 100644
> --- a/drivers/iommu/iommufd/fault.c
> +++ b/drivers/iommu/iommufd/fault.c
> @@ -10,6 +10,7 @@
>  #include <linux/module.h>
>  #include <linux/mutex.h>
>  #include <linux/pci.h>
> +#include <linux/pci-ats.h>
>  #include <linux/poll.h>
>  #include <uapi/linux/iommufd.h>
>
> @@ -27,8 +28,12 @@ static int iommufd_fault_iopf_enable(struct iommufd_device *idev)
>          * resource between PF and VFs. There is no coordination for this
>          * shared capability. This waits for a vPRI reset to recover.
>          */
> -       if (dev_is_pci(dev) && to_pci_dev(dev)->is_virtfn)
> -               return -EINVAL;
> +       if (dev_is_pci(dev)) {
> +               struct pci_dev *pdev = to_pci_dev(dev);
> +
> +               if (pdev->is_virtfn && pci_pri_supported(pdev))
> +                       return -EINVAL;
> +       }
>
>         mutex_lock(&idev->iopf_lock);
>         /* Device iopf has already been on. */
> --
> 2.25.1
>

Hi, Jason

Would you mind also taking a look at this.

Thanks