Messages in this thread Patch in this message | | | From | Eli Cohen <> | Subject | [PATCH v1] vdpa: Warn if MTU configured is too low | Date | Wed, 11 May 2022 13:56:42 +0300 |
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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 <elic@nvidia.com> --- v0 -> v1: chage pr_warn to netlink warning to userspace
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..0fb4a615f267 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)) + NL_SET_ERR_MSG_MOD(info->extack, "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
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