Re: [PATCH] iommufd: modify iommufd_fault_iopf_enable limitation

[Baolu Lu]

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>

--
baolu