[RFC PATCH 2/6] vhost-vdpa: use bind_mm device callback

[Stefano Garzarella <sgarzare@xxxxxxxxxx>]

When the user call VHOST_SET_OWNER ioctl and the vDPA device
has `use_va` set to true, let's call the bind_mm callback.

In this way we can bind the device to the user address space
and directly use the user VA.

Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
---
 drivers/vhost/vdpa.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index b08e07fc7d1f..a775d1a52c77 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -219,6 +219,17 @@ static int vhost_vdpa_reset(struct vhost_vdpa *v)
 	return vdpa_reset(vdpa);
 }
 
+static long vhost_vdpa_bind_mm(struct vhost_vdpa *v)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+
+	if (!vdpa->use_va || !ops->bind_mm)
+		return 0;
+
+	return ops->bind_mm(vdpa, v->vdev.mm, current);
+}
+
 static long vhost_vdpa_get_device_id(struct vhost_vdpa *v, u8 __user *argp)
 {
 	struct vdpa_device *vdpa = v->vdpa;
@@ -276,6 +287,10 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
 		ret = vdpa_reset(vdpa);
 		if (ret)
 			return ret;
+
+		ret = vhost_vdpa_bind_mm(v);
+		if (ret)
+			return ret;
 	} else
 		vdpa_set_status(vdpa, status);
 
@@ -679,6 +694,13 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
 		break;
 	default:
 		r = vhost_dev_ioctl(&v->vdev, cmd, argp);
+		if (!r && cmd == VHOST_SET_OWNER) {
+			r = vhost_vdpa_bind_mm(v);
+			if (r) {
+				vhost_dev_reset_owner(&v->vdev, NULL);
+				break;
+			}
+		}
 		if (r == -ENOIOCTLCMD)
 			r = vhost_vdpa_vring_ioctl(v, cmd, argp);
 		break;
-- 
2.38.1