Re: [PATCH v8 07/10] iommufd: Fault-capable hwpt attach/detach/replace

[Baolu Lu]

On 2024/10/27 22:12, Zhangfei Gao wrote:
> On Fri, 18 Oct 2024 at 10:45, Zhangfei Gao<zhangfei.gao@xxxxxxxxxx> wrote:
> > Hi, Baolu
> >
> > On Fri, 18 Oct 2024 at 09:58, Baolu Lu<baolu.lu@xxxxxxxxxxxxxxx> wrote:
> > > On 2024/10/17 21:08, Jason Gunthorpe wrote:
> > > > On Thu, Oct 17, 2024 at 08:35:24PM +0800, Zhangfei Gao wrote:
> > > >
> > > > > Yes, you are right
> > > > >    I am using SRIOV vf and stall feature, so is_virtfn == true
> > > > >
> > > > > Our ACC devices are fake pci endpoint devices which supports stall,
> > > > > And they also supports sriov
> > > > >
> > > > > So I have to ignore the limitation.
> > > > I see, so that is more complicated.
> > > >
> > > > Lu, what do you think about also checking if the PCI function has PRI
> > > > ? If not PRI assume the fault is special and doesn't follow PRI rules?
> > > >
> > > > Or maybe we can have the iommu driver tag the event as a PRI/not-PRI
> > > > fault?
> > > This limitation applies 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.
> > >
> > > In my understanding, it's fine to remove this limitation from the use
> > > case of non-PRI on SRIOV VFs. Perhaps something like below?
> > #include <linux/pci-ats.h>
> > >          if (dev_is_pci(dev)) {
> > >                  struct pci_dev *pdev = to_pci_dev(dev);
> > >                  if (pdev->is_virtfn && pci_pri_supported(pdev))
> > >                          return -EINVAL;
> > >          }
> > Yes, this works on our platform.
> Will you send this patch?
>
> Tested-by: Zhangfei Gao<zhangfei.gao@xxxxxxxxxx>

Can you please make this change a formal patch by yourself? As I don't
have hardware in hand, I'm not confident to accurately describe the
requirement or verify the new version during the upstream process.

Thanks,
baolu