[PATCH v2 10/14] vfio-iommufd: Add detach_ioas for emulated VFIO devices

[Yi Liu <yi.l.liu@xxxxxxxxx>]

this prepares for adding DETACH ioctl for emulated VFIO devices.

Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c  |  1 +
 drivers/s390/cio/vfio_ccw_ops.c   |  1 +
 drivers/s390/crypto/vfio_ap_ops.c |  1 +
 drivers/vfio/iommufd.c            | 29 +++++++++++++++++++++++++----
 include/linux/vfio.h              |  3 +++
 5 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 8ae7039b3683..8a76a84bc3c1 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1474,6 +1474,7 @@ static const struct vfio_device_ops intel_vgpu_dev_ops = {
 	.bind_iommufd	= vfio_iommufd_emulated_bind,
 	.unbind_iommufd = vfio_iommufd_emulated_unbind,
 	.attach_ioas	= vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas	= vfio_iommufd_emulated_detach_ioas,
 };
 
 static int intel_vgpu_probe(struct mdev_device *mdev)
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 5b53b94f13c7..cba4971618ff 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -632,6 +632,7 @@ static const struct vfio_device_ops vfio_ccw_dev_ops = {
 	.bind_iommufd = vfio_iommufd_emulated_bind,
 	.unbind_iommufd = vfio_iommufd_emulated_unbind,
 	.attach_ioas = vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas = vfio_iommufd_emulated_detach_ioas,
 };
 
 struct mdev_driver vfio_ccw_mdev_driver = {
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 9c01957e56b3..f99c69d40982 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1802,6 +1802,7 @@ static const struct vfio_device_ops vfio_ap_matrix_dev_ops = {
 	.bind_iommufd = vfio_iommufd_emulated_bind,
 	.unbind_iommufd = vfio_iommufd_emulated_unbind,
 	.attach_ioas = vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas = vfio_iommufd_emulated_detach_ioas,
 };
 
 static struct mdev_driver vfio_ap_matrix_driver = {
diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index 90df1f30b7fd..026f81a87dd7 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -149,14 +149,18 @@ int vfio_iommufd_emulated_bind(struct vfio_device *vdev,
 }
 EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_bind);
 
+static void __vfio_iommufd_access_destroy(struct vfio_device *vdev)
+{
+	iommufd_access_destroy(vdev->iommufd_access);
+	vdev->iommufd_access = NULL;
+}
+
 void vfio_iommufd_emulated_unbind(struct vfio_device *vdev)
 {
 	lockdep_assert_held(&vdev->dev_set->lock);
 
-	if (vdev->iommufd_access) {
-		iommufd_access_destroy(vdev->iommufd_access);
-		vdev->iommufd_access = NULL;
-	}
+	if (vdev->iommufd_access)
+		__vfio_iommufd_access_destroy(vdev);
 	iommufd_ctx_put(vdev->iommufd_ictx);
 	vdev->iommufd_ictx = NULL;
 }
@@ -168,6 +172,12 @@ int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id)
 
 	lockdep_assert_held(&vdev->dev_set->lock);
 
+	if (!vdev->iommufd_ictx)
+		return -EINVAL;
+
+	if (vdev->iommufd_access)
+		return -EBUSY;
+
 	user = iommufd_access_create(vdev->iommufd_ictx, *pt_id, &vfio_user_ops,
 				     vdev);
 	if (IS_ERR(user))
@@ -176,3 +186,14 @@ int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_attach_ioas);
+
+void vfio_iommufd_emulated_detach_ioas(struct vfio_device *vdev)
+{
+	lockdep_assert_held(&vdev->dev_set->lock);
+
+	if (!vdev->iommufd_ictx || !vdev->iommufd_access)
+		return;
+
+	__vfio_iommufd_access_destroy(vdev);
+}
+EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_detach_ioas);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 99a6a07e915c..70380d4955e1 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -125,6 +125,7 @@ int vfio_iommufd_emulated_bind(struct vfio_device *vdev,
 			       struct iommufd_ctx *ictx, u32 *out_device_id);
 void vfio_iommufd_emulated_unbind(struct vfio_device *vdev);
 int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id);
+void vfio_iommufd_emulated_detach_ioas(struct vfio_device *vdev);
 #else
 #define vfio_iommufd_physical_bind                                      \
 	((int (*)(struct vfio_device *vdev, struct iommufd_ctx *ictx,   \
@@ -142,6 +143,8 @@ int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id);
 	((void (*)(struct vfio_device *vdev)) NULL)
 #define vfio_iommufd_emulated_attach_ioas \
 	((int (*)(struct vfio_device *vdev, u32 *pt_id)) NULL)
+#define vfio_iommufd_emulated_detach_ioas \
+	((void (*)(struct vfio_device *vdev)) NULL)
 #endif
 
 /**
-- 
2.34.1