Re: [PATCH] iommufd: modify iommufd_fault_iopf_enable limitation

[Jason Gunthorpe <jgg@nvidia.com>]

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@linaro.org> 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@linaro.org>
> > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> > ---
> >  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?

Jason