On Mon, 27 Jul 2020 23:27:41 -0700 Liu Yi L <yi.l.liu@xxxxxxxxx> wrote: > Recent years, mediated device pass-through framework (e.g. vfio-mdev) > is used to achieve flexible device sharing across domains (e.g. VMs). > Also there are hardware assisted mediated pass-through solutions from > platform vendors. e.g. Intel VT-d scalable mode which supports Intel > Scalable I/O Virtualization technology. Such mdevs are called IOMMU- > backed mdevs as there are IOMMU enforced DMA isolation for such mdevs. > In kernel, IOMMU-backed mdevs are exposed to IOMMU layer by aux-domain Or a physical IOMMU backing device. > concept, which means mdevs are protected by an iommu domain which is > auxiliary to the domain that the kernel driver primarily uses for DMA > API. Details can be found in the KVM presentation as below: > > https://events19.linuxfoundation.org/wp-content/uploads/2017/12/\ > Hardware-Assisted-Mediated-Pass-Through-with-VFIO-Kevin-Tian-Intel.pdf I think letting the line exceed 80 columns is preferable so that it's clickable. Thanks, Alex > This patch extends NESTING_IOMMU ops to IOMMU-backed mdev devices. The > main requirement is to use the auxiliary domain associated with mdev. > > Cc: Kevin Tian <kevin.tian@xxxxxxxxx> > CC: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > CC: Jun Tian <jun.j.tian@xxxxxxxxx> > Cc: Alex Williamson <alex.williamson@xxxxxxxxxx> > Cc: Eric Auger <eric.auger@xxxxxxxxxx> > Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> > Cc: Joerg Roedel <joro@xxxxxxxxxx> > Cc: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> > Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx> > --- > v5 -> v6: > *) add review-by from Eric Auger. > > v1 -> v2: > *) check the iommu_device to ensure the handling mdev is IOMMU-backed > --- > drivers/vfio/vfio_iommu_type1.c | 40 ++++++++++++++++++++++++++++++++++++---- > 1 file changed, 36 insertions(+), 4 deletions(-) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index bf95a0f..9d8f252 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -2379,20 +2379,41 @@ static int vfio_iommu_resv_refresh(struct vfio_iommu *iommu, > return ret; > } > > +static struct device *vfio_get_iommu_device(struct vfio_group *group, > + struct device *dev) > +{ > + if (group->mdev_group) > + return vfio_mdev_get_iommu_device(dev); > + else > + return dev; > +} > + > static int vfio_dev_bind_gpasid_fn(struct device *dev, void *data) > { > struct domain_capsule *dc = (struct domain_capsule *)data; > unsigned long arg = *(unsigned long *)dc->data; > + struct device *iommu_device; > + > + iommu_device = vfio_get_iommu_device(dc->group, dev); > + if (!iommu_device) > + return -EINVAL; > > - return iommu_uapi_sva_bind_gpasid(dc->domain, dev, (void __user *)arg); > + return iommu_uapi_sva_bind_gpasid(dc->domain, iommu_device, > + (void __user *)arg); > } > > static int vfio_dev_unbind_gpasid_fn(struct device *dev, void *data) > { > struct domain_capsule *dc = (struct domain_capsule *)data; > unsigned long arg = *(unsigned long *)dc->data; > + struct device *iommu_device; > > - iommu_uapi_sva_unbind_gpasid(dc->domain, dev, (void __user *)arg); > + iommu_device = vfio_get_iommu_device(dc->group, dev); > + if (!iommu_device) > + return -EINVAL; > + > + iommu_uapi_sva_unbind_gpasid(dc->domain, iommu_device, > + (void __user *)arg); > return 0; > } > > @@ -2401,8 +2422,13 @@ static int __vfio_dev_unbind_gpasid_fn(struct device *dev, void *data) > struct domain_capsule *dc = (struct domain_capsule *)data; > struct iommu_gpasid_bind_data *unbind_data = > (struct iommu_gpasid_bind_data *)dc->data; > + struct device *iommu_device; > + > + iommu_device = vfio_get_iommu_device(dc->group, dev); > + if (!iommu_device) > + return -EINVAL; > > - iommu_sva_unbind_gpasid(dc->domain, dev, unbind_data); > + iommu_sva_unbind_gpasid(dc->domain, iommu_device, unbind_data); > return 0; > } > > @@ -3060,8 +3086,14 @@ static int vfio_dev_cache_invalidate_fn(struct device *dev, void *data) > { > struct domain_capsule *dc = (struct domain_capsule *)data; > unsigned long arg = *(unsigned long *)dc->data; > + struct device *iommu_device; > + > + iommu_device = vfio_get_iommu_device(dc->group, dev); > + if (!iommu_device) > + return -EINVAL; > > - iommu_uapi_cache_invalidate(dc->domain, dev, (void __user *)arg); > + iommu_uapi_cache_invalidate(dc->domain, iommu_device, > + (void __user *)arg); > return 0; > } >
