[RFC 1/3] vdpa: support exposing the config size to userspace

Longpeng(Mike)
2022-01-17T09:29:37Z

- GET_CONFIG_SIZE: the size of the virtio config space

Signed-off-by: Longpeng <longpeng2@huawei.com>
---
drivers/vhost/vdpa.c | 17 +++++++++++++++++
include/uapi/linux/vhost.h | 4 ++++
2 files changed, 21 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 29cced1cd277..1eea14a4ea56 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -355,6 +355,20 @@ static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp)
return 0;
}

+static long vhost_vdpa_get_config_size(struct vhost_vdpa *v, u32 __user *argp)
+{
+ struct vdpa_device *vdpa = v->vdpa;
+ const struct vdpa_config_ops *ops = vdpa->config;
+ u32 size;
+
+ size = ops->get_config_size(vdpa);
+
+ if (copy_to_user(argp, &size, sizeof(size)))
+ return -EFAULT;
+
+ return 0;
+}
+
static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
void __user *argp)
{
@@ -492,6 +506,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
case VHOST_VDPA_GET_IOVA_RANGE:
r = vhost_vdpa_get_iova_range(v, argp);
break;
+ case VHOST_VDPA_GET_CONFIG_SIZE:
+ r = vhost_vdpa_get_config_size(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 c998860d7bbc..bc74e95a273a 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -150,4 +150,8 @@
/* Get the valid iova range */
#define VHOST_VDPA_GET_IOVA_RANGE _IOR(VHOST_VIRTIO, 0x78, \
struct vhost_vdpa_iova_range)
+
+/* Get the config size */
+#define VHOST_VDPA_GET_CONFIG_SIZE _IOR(VHOST_VIRTIO, 0x79, __u32)
+
#endif
--
2.23.0