Following the recommendation in virio spec 1.1, a device offering
VIRTIO_NET_F_MTU should set the mtu to at least 1280 bytes.
Print a warning if this recommendation is not met.
Signed-off-by: Eli Cohen <[email protected]>
---
drivers/vdpa/vdpa.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index 91f4c13c7c7c..961168fe9094 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -583,6 +583,9 @@ vdpa_nl_cmd_mgmtdev_get_dumpit(struct sk_buff *msg, struct netlink_callback *cb)
BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) | \
BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MAX_VQP))
+/* Recommended virtio spec 1.1 section 5.1.4.1 */
+#define VIRTIO_MIN_PREFERRED_MTU 1280
+
static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *info)
{
struct vdpa_dev_set_config config = {};
@@ -634,6 +637,10 @@ static int vdpa_nl_cmd_dev_add_set_doit(struct sk_buff *skb, struct genl_info *i
err = PTR_ERR(mdev);
goto err;
}
+ if ((mdev->supported_features & BIT_ULL(VIRTIO_NET_F_MTU)) &&
+ (config.mask & BIT_ULL(VDPA_ATTR_DEV_NET_CFG_MTU) &&
+ config.net.mtu < VIRTIO_MIN_PREFERRED_MTU))
+ pr_warn("MTU is below recommended value\n");
if ((config.mask & mdev->config_attr_mask) != config.mask) {
NL_SET_ERR_MSG_MOD(info->extack,
"All provided attributes are not supported");
@@ -1135,7 +1142,7 @@ static const struct nla_policy vdpa_nl_policy[VDPA_ATTR_MAX + 1] = {
[VDPA_ATTR_DEV_NAME] = { .type = NLA_STRING },
[VDPA_ATTR_DEV_NET_CFG_MACADDR] = NLA_POLICY_ETH_ADDR,
/* virtio spec 1.1 section 5.1.4.1 for valid MTU range */
- [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, 68),
+ [VDPA_ATTR_DEV_NET_CFG_MTU] = NLA_POLICY_MIN(NLA_U16, ETH_MIN_MTU),
};
static const struct genl_ops vdpa_nl_ops[] = {
--
2.35.1