iommu/arm-smmu: put iommu_domain pointer in dev->archdata.iommu

In preparation for nested translation support, stick a pointer to the
iommu_domain in dev->archdata.iommu. This makes it much easier to grab
hold of the physical group configuration (e.g. cbndx) when dealing with
vSMMU accesses from a guest.

Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 14 insertions, 3 deletions

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 38f8d670afb3..e8d311152203 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1213,6 +1213,11 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
                 return -ENXIO;
         }
 
+        if (dev->archdata.iommu) {
+                dev_err(dev, "already attached to IOMMU domain\n");
+                return -EEXIST;
+        }
+
         /*
          * Sanity check the domain. We don't support domains across
          * different SMMUs.
@@ -1239,7 +1244,10 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
         if (!cfg)
                 return -ENODEV;
 
-        return arm_smmu_domain_add_master(smmu_domain, cfg);
+        ret = arm_smmu_domain_add_master(smmu_domain, cfg);
+        if (!ret)
+                dev->archdata.iommu = domain;
+        return ret;
 }
 
 static void arm_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
@@ -1248,8 +1256,11 @@ static void arm_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
         struct arm_smmu_master_cfg *cfg;
 
         cfg = find_smmu_master_cfg(dev);
-        if (cfg)
-                arm_smmu_domain_remove_master(smmu_domain, cfg);
+        if (!cfg)
+                return;
+
+        dev->archdata.iommu = NULL;
+        arm_smmu_domain_remove_master(smmu_domain, cfg);
 }
 
 static bool arm_smmu_pte_is_contiguous_range(unsigned long addr,