1 files changed, 111 insertions, 0 deletions

diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
index 106506143896..e425573a1787 100644
--- a/drivers/iommu/iommu-sva-lib.c
+++ b/drivers/iommu/iommu-sva-lib.c
@@ -4,6 +4,7 @@
  */
 #include <linux/mutex.h>
 #include <linux/sched/mm.h>
+#include <linux/iommu.h>
 
 #include "iommu-sva-lib.h"
 
@@ -69,3 +70,113 @@ struct mm_struct *iommu_sva_find(ioasid_t pasid)
 	return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero);
 }
 EXPORT_SYMBOL_GPL(iommu_sva_find);
+
+/**
+ * iommu_sva_bind_device() - Bind a process address space to a device
+ * @dev: the device
+ * @mm: the mm to bind, caller must hold a reference to mm_users
+ *
+ * Create a bond between device and address space, allowing the device to
+ * access the mm using the PASID returned by iommu_sva_get_pasid(). If a
+ * bond already exists between @device and @mm, an additional internal
+ * reference is taken. Caller must call iommu_sva_unbind_device()
+ * to release each reference.
+ *
+ * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to
+ * initialize the required SVA features.
+ *
+ * On error, returns an ERR_PTR value.
+ */
+struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm)
+{
+	struct iommu_domain *domain;
+	struct iommu_sva *handle;
+	ioasid_t max_pasids;
+	int ret;
+
+	max_pasids = dev->iommu->max_pasids;
+	if (!max_pasids)
+		return ERR_PTR(-EOPNOTSUPP);
+
+	/* Allocate mm->pasid if necessary. */
+	ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1);
+	if (ret)
+		return ERR_PTR(ret);
+
+	handle = kzalloc(sizeof(*handle), GFP_KERNEL);
+	if (!handle)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_lock(&iommu_sva_lock);
+	/* Search for an existing domain. */
+	domain = iommu_get_domain_for_dev_pasid(dev, mm->pasid,
+						IOMMU_DOMAIN_SVA);
+	if (IS_ERR(domain)) {
+		ret = PTR_ERR(domain);
+		goto out_unlock;
+	}
+
+	if (domain) {
+		domain->users++;
+		goto out;
+	}
+
+	/* Allocate a new domain and set it on device pasid. */
+	domain = iommu_sva_domain_alloc(dev, mm);
+	if (!domain) {
+		ret = -ENOMEM;
+		goto out_unlock;
+	}
+
+	ret = iommu_attach_device_pasid(domain, dev, mm->pasid);
+	if (ret)
+		goto out_free_domain;
+	domain->users = 1;
+out:
+	mutex_unlock(&iommu_sva_lock);
+	handle->dev = dev;
+	handle->domain = domain;
+
+	return handle;
+
+out_free_domain:
+	iommu_domain_free(domain);
+out_unlock:
+	mutex_unlock(&iommu_sva_lock);
+	kfree(handle);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_bind_device);
+
+/**
+ * iommu_sva_unbind_device() - Remove a bond created with iommu_sva_bind_device
+ * @handle: the handle returned by iommu_sva_bind_device()
+ *
+ * Put reference to a bond between device and address space. The device should
+ * not be issuing any more transaction for this PASID. All outstanding page
+ * requests for this PASID must have been flushed to the IOMMU.
+ */
+void iommu_sva_unbind_device(struct iommu_sva *handle)
+{
+	struct iommu_domain *domain = handle->domain;
+	ioasid_t pasid = domain->mm->pasid;
+	struct device *dev = handle->dev;
+
+	mutex_lock(&iommu_sva_lock);
+	if (--domain->users == 0) {
+		iommu_detach_device_pasid(domain, dev, pasid);
+		iommu_domain_free(domain);
+	}
+	mutex_unlock(&iommu_sva_lock);
+	kfree(handle);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);
+
+u32 iommu_sva_get_pasid(struct iommu_sva *handle)
+{
+	struct iommu_domain *domain = handle->domain;
+
+	return domain->mm->pasid;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);