Hi Jason, On Fri, 7 Feb 2025 10:46:03 -0400 Jason Gunthorpe <j...@nvidia.com> wrote:
> virtio has the complication that it sometimes wants to return a paging > domain for IDENTITY which makes this conversion a little different > than other drivers. > > Add a viommu_domain_alloc_paging() that combines > viommu_domain_alloc() and viommu_domain_finalise() to always return a > fully initialized and finalized paging domain. > Slightly off the topic, still related to paging domain. virtio spec for page table extension was introduced a while ago[1], which adds support for guest owned page tables for paging domains. Do you foresee the implementation can leverage your generic iommu_pt work? i.e. for building guest IO page tables. It will add a new flavor (page table based in addition to map/unmap) to viommu_domain_alloc_paging() i think. [1] https://lore.kernel.org/all/20231006160947.2227396-8-jean-phili...@linaro.org/T/ > Use viommu_domain_alloc_identity() to implement the special non-bypass > IDENTITY flow by calling viommu_domain_alloc_paging() then > viommu_domain_map_identity(). > > Remove support for deferred finalize and the vdomain->mutex. > > Remove core support for domain_alloc() IDENTITY as virtio was the last > driver using it. > > Signed-off-by: Jason Gunthorpe <j...@nvidia.com> > --- > drivers/iommu/iommu.c | 6 -- > drivers/iommu/virtio-iommu.c | 114 > ++++++++++++++++------------------- 2 files changed, 53 > insertions(+), 67 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index ee33d26dfcd40d..73a05b34de4768 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1599,12 +1599,6 @@ static struct iommu_domain > *__iommu_alloc_identity_domain(struct device *dev) domain = > ops->domain_alloc_identity(dev); if (IS_ERR(domain)) > return domain; > - } else if (ops->domain_alloc) { > - domain = ops->domain_alloc(IOMMU_DOMAIN_IDENTITY); > - if (!domain) > - return ERR_PTR(-ENOMEM); > - if (IS_ERR(domain)) > - return domain; > } else { > return ERR_PTR(-EOPNOTSUPP); > } > diff --git a/drivers/iommu/virtio-iommu.c > b/drivers/iommu/virtio-iommu.c index c71a996760bddb..79b471c03b6ee4 > 100644 --- a/drivers/iommu/virtio-iommu.c > +++ b/drivers/iommu/virtio-iommu.c > @@ -63,7 +63,6 @@ struct viommu_mapping { > struct viommu_domain { > struct iommu_domain domain; > struct viommu_dev *viommu; > - struct mutex mutex; /* protects > viommu pointer */ unsigned int id; > u32 map_flags; > > @@ -97,6 +96,8 @@ struct viommu_event { > }; > }; > > +static struct viommu_domain viommu_identity_domain; > + > #define to_viommu_domain(domain) \ > container_of(domain, struct viommu_domain, domain) > > @@ -653,65 +654,45 @@ static void viommu_event_handler(struct > virtqueue *vq) > /* IOMMU API */ > > -static struct iommu_domain *viommu_domain_alloc(unsigned type) > +static struct iommu_domain *viommu_domain_alloc_paging(struct device > *dev) { > - struct viommu_domain *vdomain; > - > - if (type != IOMMU_DOMAIN_UNMANAGED && > - type != IOMMU_DOMAIN_DMA && > - type != IOMMU_DOMAIN_IDENTITY) > - return NULL; > - > - vdomain = kzalloc(sizeof(*vdomain), GFP_KERNEL); > - if (!vdomain) > - return NULL; > - > - mutex_init(&vdomain->mutex); > - spin_lock_init(&vdomain->mappings_lock); > - vdomain->mappings = RB_ROOT_CACHED; > - > - return &vdomain->domain; > -} > - > -static int viommu_domain_finalise(struct viommu_endpoint *vdev, > - struct iommu_domain *domain) > -{ > - int ret; > - unsigned long viommu_page_size; > + struct viommu_endpoint *vdev = dev_iommu_priv_get(dev); > struct viommu_dev *viommu = vdev->viommu; > - struct viommu_domain *vdomain = to_viommu_domain(domain); > + unsigned long viommu_page_size; > + struct viommu_domain *vdomain; > + int ret; > > viommu_page_size = 1UL << __ffs(viommu->pgsize_bitmap); > if (viommu_page_size > PAGE_SIZE) { > dev_err(vdev->dev, > "granule 0x%lx larger than system page size > 0x%lx\n", viommu_page_size, PAGE_SIZE); > - return -ENODEV; > + return ERR_PTR(-ENODEV); > } > > + vdomain = kzalloc(sizeof(*vdomain), GFP_KERNEL); > + if (!vdomain) > + return ERR_PTR(-ENOMEM); > + > + spin_lock_init(&vdomain->mappings_lock); > + vdomain->mappings = RB_ROOT_CACHED; > + > ret = ida_alloc_range(&viommu->domain_ids, > viommu->first_domain, viommu->last_domain, GFP_KERNEL); > - if (ret < 0) > - return ret; > - > - vdomain->id = (unsigned int)ret; > - > - domain->pgsize_bitmap = viommu->pgsize_bitmap; > - domain->geometry = viommu->geometry; > - > - vdomain->map_flags = viommu->map_flags; > - vdomain->viommu = viommu; > - > - if (domain->type == IOMMU_DOMAIN_IDENTITY) { > - ret = viommu_domain_map_identity(vdev, vdomain); > - if (ret) { > - ida_free(&viommu->domain_ids, vdomain->id); > - vdomain->viommu = NULL; > - return ret; > - } > + if (ret < 0) { > + kfree(vdomain); > + return ERR_PTR(ret); > } > > - return 0; > + vdomain->id = (unsigned int)ret; > + > + vdomain->domain.pgsize_bitmap = viommu->pgsize_bitmap; > + vdomain->domain.geometry = viommu->geometry; > + > + vdomain->map_flags = viommu->map_flags; > + vdomain->viommu = viommu; > + > + return &vdomain->domain; > } > > static void viommu_domain_free(struct iommu_domain *domain) > @@ -727,6 +708,28 @@ static void viommu_domain_free(struct > iommu_domain *domain) kfree(vdomain); > } > > +static struct iommu_domain *viommu_domain_alloc_identity(struct > device *dev) +{ > + struct viommu_endpoint *vdev = dev_iommu_priv_get(dev); > + struct iommu_domain *domain; > + int ret; > + > + if (virtio_has_feature(vdev->viommu->vdev, > + VIRTIO_IOMMU_F_BYPASS_CONFIG)) > + return &viommu_identity_domain.domain; > + > + domain = viommu_domain_alloc_paging(dev); > + if (IS_ERR(domain)) > + return domain; > + > + ret = viommu_domain_map_identity(vdev, > to_viommu_domain(domain)); > + if (ret) { > + viommu_domain_free(domain); > + return ERR_PTR(ret); > + } > + return domain; > +} > + > static int viommu_attach_dev(struct iommu_domain *domain, struct > device *dev) { > int ret = 0; > @@ -734,20 +737,8 @@ static int viommu_attach_dev(struct iommu_domain > *domain, struct device *dev) struct viommu_endpoint *vdev = > dev_iommu_priv_get(dev); struct viommu_domain *vdomain = > to_viommu_domain(domain); > - mutex_lock(&vdomain->mutex); > - if (!vdomain->viommu) { > - /* > - * Properly initialize the domain now that we know > which viommu > - * owns it. > - */ > - ret = viommu_domain_finalise(vdev, domain); > - } else if (vdomain->viommu != vdev->viommu) { > - ret = -EINVAL; > - } > - mutex_unlock(&vdomain->mutex); > - > - if (ret) > - return ret; > + if (vdomain->viommu != vdev->viommu) > + return -EINVAL; > > /* > * In the virtio-iommu device, when attaching the endpoint > to a new @@ -1098,7 +1089,8 @@ static bool viommu_capable(struct > device *dev, enum iommu_cap cap) static struct iommu_ops viommu_ops = > { .identity_domain = &viommu_identity_domain.domain, > .capable = viommu_capable, > - .domain_alloc = viommu_domain_alloc, > + .domain_alloc_identity = viommu_domain_alloc_identity, > + .domain_alloc_paging = viommu_domain_alloc_paging, > .probe_device = viommu_probe_device, > .release_device = viommu_release_device, > .device_group = viommu_device_group,
