Re: [PATCH v2 1/3] vdpa: support exposing the config size to userspace

[Stefano Garzarella <sgarzare@redhat.com>]

On Tue, Mar 15, 2022 at 11:25:51AM +0800, Longpeng(Mike) wrote:
>From: Longpeng <longpeng2@huawei.com>
>
>- GET_CONFIG_SIZE: return the size of the virtio config space.
>
>The size contains the fields which are conditional on feature
>bits.
>
>Acked-by: Jason Wang <jasowang@redhat.com>
>Signed-off-by: Longpeng <longpeng2@huawei.com>
>---
> drivers/vhost/vdpa.c       | 17 +++++++++++++++++
> include/linux/vdpa.h       |  3 ++-
> include/uapi/linux/vhost.h |  4 ++++
> 3 files changed, 23 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>index ec5249e..605c7ae 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);

get_config_size() returns a size_t, perhaps we could have a comment here 
where we say we don't expect there to be an overflow.

I don't have a strong opinion on this, and I wouldn't want to get you to 
repin just for that, so:

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>