iommu/amd: Add invalidate-context call-back

This call-back is invoked when the task that is bound to a
pasid is about to exit. The driver can use it to shutdown
all context related to that context in a safe way.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

drivers/iommu/amd_iommu_v2.c

@@ -63,6 +63,7 @@ struct device_state {
 	int pasid_levels;
 	int max_pasids;
 	amd_iommu_invalid_ppr_cb inv_ppr_cb;
+	amd_iommu_invalidate_ctx inv_ctx_cb;
 	spinlock_t lock;
 	wait_queue_head_t wq;
 };
@@ -637,6 +638,9 @@ static int task_exit(struct notifier_block *nb, unsigned long e, void *data)
 		dev_state = pasid_state->device_state;
 		pasid     = pasid_state->pasid;
 
+		if (pasid_state->device_state->inv_ctx_cb)
+			dev_state->inv_ctx_cb(dev_state->pdev, pasid);
+
 		unbind_pasid(dev_state, pasid);
 
 		/* Task may be in the list multiple times */
@@ -881,6 +885,37 @@ int amd_iommu_set_invalid_ppr_cb(struct pci_dev *pdev,
 }
 EXPORT_SYMBOL(amd_iommu_set_invalid_ppr_cb);
 
+int amd_iommu_set_invalidate_ctx_cb(struct pci_dev *pdev,
+				    amd_iommu_invalidate_ctx cb)
+{
+	struct device_state *dev_state;
+	unsigned long flags;
+	u16 devid;
+	int ret;
+
+	if (!amd_iommu_v2_supported())
+		return -ENODEV;
+
+	devid = device_id(pdev);
+
+	spin_lock_irqsave(&state_lock, flags);
+
+	ret = -EINVAL;
+	dev_state = state_table[devid];
+	if (dev_state == NULL)
+		goto out_unlock;
+
+	dev_state->inv_ctx_cb = cb;
+
+	ret = 0;
+
+out_unlock:
+	spin_unlock_irqrestore(&state_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(amd_iommu_set_invalidate_ctx_cb);
+
 static int __init amd_iommu_v2_init(void)
 {
 	size_t state_table_size;

include/linux/amd-iommu.h

@@ -145,6 +145,23 @@ struct amd_iommu_device_info {
 extern int amd_iommu_device_info(struct pci_dev *pdev,
 				 struct amd_iommu_device_info *info);
 
+/**
+ * amd_iommu_set_invalidate_ctx_cb() - Register a call-back for invalidating
+ *				       a pasid context. This call-back is
+ *				       invoked when the IOMMUv2 driver needs to
+ *				       invalidate a PASID context, for example
+ *				       because the task that is bound to that
+ *				       context is about to exit.
+ *
+ * @pdev: The PCI device the call-back should be registered for
+ * @cb: The call-back function
+ */
+
+typedef void (*amd_iommu_invalidate_ctx)(struct pci_dev *pdev, int pasid);
+
+extern int amd_iommu_set_invalidate_ctx_cb(struct pci_dev *pdev,
+					   amd_iommu_invalidate_ctx cb);
+
 #else
 
 static inline int amd_iommu_detect(void) { return -ENODEV; }