Re: [PATCH] iommufd: modify iommufd_fault_iopf_enable limitation

[Zhangfei Gao]

On Thu, 7 Nov 2024 at 01:52, Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx> wrote:
>
> On 11/6/24 21:59, Jason Gunthorpe wrote:
> > On Wed, Nov 06, 2024 at 05:47:09AM +0000, Zhangfei Gao wrote:
> >> 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. */
> >>>
> >> Hi, Jason
> >>
> >> Would you mind also taking a look at this.
> > Lu? Are you OK with this?
>
> This change looks good to me. But the s-o-b chain would make more sense
> if we can make it like this,
>
> Co-developed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Signed-off-by: Zhangfei Gao<zhangfei.gao@xxxxxxxxxx>
>
> With this addressed,
>
> Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

Thanks Baolu,
Have fixed it.

Thanks