iommu: Add ops->domain_alloc_sva()

Make a new op that receives the device and the mm_struct that the SVA
domain should be created for. Unlike domain_alloc_paging() the dev
argument is never NULL here.

This allows drivers to fully initialize the SVA domain and allocate the
mmu_notifier during allocation. It allows the notifier lifetime to follow
the lifetime of the iommu_domain.

Since we have only one call site, upgrade the new op to return ERR_PTR
instead of NULL.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Tina Zhang <tina.zhang@intel.com>
Link: https://lore.kernel.org/r/20240311090843.133455-15-vasant.hegde@amd.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240416080656.60968-12-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index 640acc8..18a35e7 100644 (file)
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -108,8 +108,8 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
 
        /* Allocate a new domain and set it on device pasid. */
        domain = iommu_sva_domain_alloc(dev, mm);
-       if (!domain) {
-               ret = -ENOMEM;
+       if (IS_ERR(domain)) {
+               ret = PTR_ERR(domain);
                goto out_free_handle;
        }
 
@@ -283,9 +283,15 @@ struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
        const struct iommu_ops *ops = dev_iommu_ops(dev);
        struct iommu_domain *domain;
 
-       domain = ops->domain_alloc(IOMMU_DOMAIN_SVA);
-       if (!domain)
-               return NULL;
+       if (ops->domain_alloc_sva) {
+               domain = ops->domain_alloc_sva(dev, mm);
+               if (IS_ERR(domain))
+                       return domain;
+       } else {
+               domain = ops->domain_alloc(IOMMU_DOMAIN_SVA);
+               if (!domain)
+                       return ERR_PTR(-ENOMEM);
+       }
 
        domain->type = IOMMU_DOMAIN_SVA;
        mmgrab(mm);

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index e6549bd..f4cdffa 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -517,6 +517,7 @@ static inline int __iommu_copy_struct_from_user_array(
  *                     Upon failure, ERR_PTR must be returned.
  * @domain_alloc_paging: Allocate an iommu_domain that can be used for
  *                       UNMANAGED, DMA, and DMA_FQ domain types.
+ * @domain_alloc_sva: Allocate an iommu_domain for Shared Virtual Addressing.
  * @probe_device: Add device to iommu driver handling
  * @release_device: Remove device from iommu driver handling
  * @probe_finalize: Do final setup work after the device is added to an IOMMU
@@ -557,6 +558,8 @@ struct iommu_ops {
                struct device *dev, u32 flags, struct iommu_domain *parent,
                const struct iommu_user_data *user_data);
        struct iommu_domain *(*domain_alloc_paging)(struct device *dev);
+       struct iommu_domain *(*domain_alloc_sva)(struct device *dev,
+                                                struct mm_struct *mm);
 
        struct iommu_device *(*probe_device)(struct device *dev);
        void (*release_device)(struct device *dev);