Re: [PATCH 8/8] iommu/vt-d: Add set_dev_pasid callback for nested domain

[Baolu Lu]

On 2023/12/14 10:55, Yang, Weijiang wrote:
> On 11/27/2023 2:34 PM, Yi Liu wrote:
> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> >
> > This allows the upper layers to set a nested type domain to a PASID of a
> > device if the PASID feature is supported by the IOMMU hardware.
> >
> > The set_dev_pasid callback for non-nest domain has already be there, so
> > this only needs to add it for nested domains.
> >
> > Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
> > ---
> >   drivers/iommu/intel/nested.c | 47 ++++++++++++++++++++++++++++++++++++
> >   1 file changed, 47 insertions(+)
> >
> > diff --git a/drivers/iommu/intel/nested.c b/drivers/iommu/intel/nested.c
> > index 44ad48db7ea0..f6f687750104 100644
> > --- a/drivers/iommu/intel/nested.c
> > +++ b/drivers/iommu/intel/nested.c
> > @@ -68,6 +68,52 @@ static int intel_nested_attach_dev(struct 
> > iommu_domain *domain,
> >       return 0;
> >   }
> > +static int intel_nested_set_dev_pasid(struct iommu_domain *domain,
> > +                      struct device *dev, ioasid_t pasid)
> > +{
> > +    struct device_domain_info *info = dev_iommu_priv_get(dev);
> > +    struct dmar_domain *dmar_domain = to_dmar_domain(domain);
> > +    struct intel_iommu *iommu = info->iommu;
> > +    struct dev_pasid_info *dev_pasid;
> > +    unsigned long flags;
> > +    int ret = 0;
> > +
> > +    if (!pasid_supported(iommu))
> > +        return -EOPNOTSUPP;
> > +
> > +    if (iommu->agaw < dmar_domain->s2_domain->agaw)
> > +        return -EINVAL;
> > +
> > +    ret = 
> > prepare_domain_attach_device(&dmar_domain->s2_domain->domain, dev);
> > +    if (ret)
> > +        return ret;
> > +
> > +    dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
> > +    if (!dev_pasid)
> > +        return -ENOMEM;
> > +
> > +    ret = domain_attach_iommu(dmar_domain, iommu);
> > +    if (ret)
> > +        goto err_free;
> > +
> > +    ret = intel_pasid_setup_nested(iommu, dev, pasid, dmar_domain);
> > +    if (ret)
> > +        goto err_detach_iommu;
> > +
> > +    dev_pasid->dev = dev;
> > +    dev_pasid->pasid = pasid;
> > +    spin_lock_irqsave(&dmar_domain->lock, flags);
> > +    list_add(&dev_pasid->link_domain, &dmar_domain->dev_pasids);
> > +    spin_unlock_irqrestore(&dmar_domain->lock, flags);
>
> ---> list_add(&dev_pasid->link_domain, &dmar_domain->dev_pasids);
>
> dev_pasid is linked at later time, this leads to 
> domain->has_iotlb_device is not correctly set, which finally results 
> into a missing of device iotlb flush in iommu_flush_dev_iotlb()when it's 
> called.
> Check this call path:
> domain_attach_iommu()->domain_update_iommu_cap()->domain_update_iotlb()->domain->has_iotlb_device = has_iotlb_device; The ugly fixup is to call domain_update_iommu_cap() or domain_update_iotlb() here again before return.
> The similar issue is in intel_iommu_set_dev_pasid() and 
> intel_nested_attach_dev().

Yes, domain->has_iotlb_device must be updated whenever a domain is
attached to (or removed from) a RID or PASID. I would be grateful if you
could post some patches to fix the set_device_pasid and
nested_attach_dev paths.

I assume Yi can fix this series in the next version.

Best regards,
baolu