Re: [iproute2-next v2 4/4] vdpa: Enable user to set mtu of the vdpa device

On Sat, Dec 18, 2021 at 01:53:01PM -0700, David Ahern wrote:

On 12/17/21 1:08 AM, Parav Pandit wrote:

quoted

@@ -204,6 +217,8 @@ static void vdpa_opts_put(struct nlmsghdr *nlh, struct vdpa *vdpa)
 	if (opts->present & VDPA_OPT_VDEV_MAC)
 		mnl_attr_put(nlh, VDPA_ATTR_DEV_NET_CFG_MACADDR,
 			     sizeof(opts->mac), opts->mac);
+	if (opts->present & VDPA_OPT_VDEV_MTU)
+		mnl_attr_put_u16(nlh, VDPA_ATTR_DEV_NET_CFG_MTU, opts->mtu);

Why limit the MTU to a u16? Eric for example is working on "Big TCP"
where IPv6 can work with Jumbograms where mtu can be > 64k.

https://datatracker.ietf.org/doc/html/rfc2675

Well it's 16 bit at the virtio level, though we can extend that of
course. Making it match for now removes need for validation.
-- 
MST