[PATCH v4 3/4] vhost-vdpa: uAPI to stop the device

Eugenio Pérez
2022-05-26T12:44:52Z

The ioctl adds support for stop the device from userspace.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
drivers/vhost/vdpa.c | 18 ++++++++++++++++++
include/uapi/linux/vhost.h | 14 ++++++++++++++
2 files changed, 32 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 32713db5831d..d1d19555c4b7 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -478,6 +478,21 @@ static long vhost_vdpa_get_vqs_count(struct vhost_vdpa *v, u32 __user *argp)
return 0;
}

+static long vhost_vdpa_stop(struct vhost_vdpa *v, u32 __user *argp)
+{
+ struct vdpa_device *vdpa = v->vdpa;
+ const struct vdpa_config_ops *ops = vdpa->config;
+ int stop;
+
+ if (!ops->stop)
+ return -EOPNOTSUPP;
+
+ if (copy_from_user(&stop, argp, sizeof(stop)))
+ return -EFAULT;
+
+ return ops->stop(vdpa, stop);
+}
+
static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
void __user *argp)
{
@@ -650,6 +665,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
case VHOST_VDPA_GET_VQS_COUNT:
r = vhost_vdpa_get_vqs_count(v, argp);
break;
+ case VHOST_VDPA_STOP:
+ r = vhost_vdpa_stop(v, argp);
+ break;
default:
r = vhost_dev_ioctl(&v->vdev, cmd, argp);
if (r == -ENOIOCTLCMD)
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index cab645d4a645..c7e47b29bf61 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -171,4 +171,18 @@
#define VHOST_VDPA_SET_GROUP_ASID _IOW(VHOST_VIRTIO, 0x7C, \
struct vhost_vring_state)

+/* Stop or resume a device so it does not process virtqueue requests anymore
+ *
+ * After the return of ioctl with stop != 0, the device must finish any
+ * pending operations like in flight requests. It must also preserve all
+ * the necessary state (the virtqueue vring base plus the possible device
+ * specific states) that is required for restoring in the future. The
+ * device must not change its configuration after that point.
+ *
+ * After the return of ioctl with stop == 0, the device can continue
+ * processing buffers as long as typical conditions are met (vq is enabled,
+ * DRIVER_OK status bit is enabled, etc).
+ */
+#define VHOST_VDPA_STOP _IOW(VHOST_VIRTIO, 0x7D, int)
+
#endif
--
2.31.1