vhost-vdpa: switch to use vhost-vdpa specific IOTLB

To ease the implementation of per group ASID support for vDPA
device. This patch switches to use a vhost-vdpa specific IOTLB to
avoid the unnecessary refactoring of the vhost core.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Gautam Dawar <gdawar@xilinx.com>
Message-Id: <20220330180436.24644-5-gdawar@xilinx.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vdpa.c

@@ -39,6 +39,7 @@ struct vhost_vdpa {
 	struct vhost_virtqueue *vqs;
 	struct completion completion;
 	struct vdpa_device *vdpa;
+	struct vhost_iotlb *iotlb;
 	struct device dev;
 	struct cdev cdev;
 	atomic_t opened;
@@ -589,12 +590,11 @@ static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v,
 
 static void vhost_vdpa_iotlb_free(struct vhost_vdpa *v)
 {
-	struct vhost_dev *dev = &v->vdev;
-	struct vhost_iotlb *iotlb = dev->iotlb;
+	struct vhost_iotlb *iotlb = v->iotlb;
 
 	vhost_vdpa_iotlb_unmap(v, iotlb, 0ULL, 0ULL - 1);
-	kfree(dev->iotlb);
-	dev->iotlb = NULL;
+	kfree(v->iotlb);
+	v->iotlb = NULL;
 }
 
 static int perm_to_iommu_flags(u32 perm)
@@ -876,7 +876,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
 	struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev);
 	struct vdpa_device *vdpa = v->vdpa;
 	const struct vdpa_config_ops *ops = vdpa->config;
-	struct vhost_iotlb *iotlb = dev->iotlb;
+	struct vhost_iotlb *iotlb = v->iotlb;
 	int r = 0;
 
 	mutex_lock(&dev->mutex);
@@ -1017,15 +1017,15 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
 	vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false,
 		       vhost_vdpa_process_iotlb_msg);
 
-	dev->iotlb = vhost_iotlb_alloc(0, 0);
-	if (!dev->iotlb) {
+	v->iotlb = vhost_iotlb_alloc(0, 0);
+	if (!v->iotlb) {
 		r = -ENOMEM;
 		goto err_init_iotlb;
 	}
 
 	r = vhost_vdpa_alloc_domain(v);
 	if (r)
-		goto err_init_iotlb;
+		goto err_alloc_domain;
 
 	vhost_vdpa_set_iova_range(v);
 
@@ -1033,6 +1033,8 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
 
 	return 0;
 
+err_alloc_domain:
+	vhost_vdpa_iotlb_free(v);
 err_init_iotlb:
 	vhost_dev_cleanup(&v->vdev);
 	kfree(vqs);