Re: [PATCH] app/testpmd: add VLAN priority insert support

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 12 Jun 2026 16:14:11 +0800
Xingui Yang <yangxingui@huawei.com> wrote:

> The tx_vlan set command currently only accepts a VLAN ID in range
> [0, 4095].  This patch adds support for an extended format that includes
> 802.1p priority and CFI bits, allowing users to set the VLAN priority
> tag when inserting VLAN headers in TX packets.
> 
> The extended format is:
>   bit 0-11:  VLAN ID (0-4095)
>   bit 12:    CFI (Canonical Format Indicator)
>   bit 13-15: Priority (0-7, 802.1p CoS)
> 
> This is consistent with the VLAN tag structure used by
> rte_eth_dev_set_vlan_pvid() where the PVID field encodes VLAN ID, CFI
> and priority in the same format.
> 
> A new command line option --enable-vlan-priority is added to enable this
> feature. By default, the feature is disabled to maintain backward
> compatibility with existing users. When enabled, the
> vlan_id_is_invalid() function allows any 16-bit value to pass, while the
> full 16-bit value (including CFI and priority bits) is passed to the
> driver for hardware VLAN insertion.
> 
> Signed-off-by: Xingui Yang <yangxingui@huawei.com>
> ---


Having ability to set priority bits is good, and testpmd should allow it.
The mbuf vlan_tci is already a full 16-bit TCI (priority/CFI/VID), and
the TX insert path copies tx_vlan_id straight into it.  So priority
insert already works; the only thing in the way is the < 4096 check.

Do you actually need a new option for this?  Both of_push_vlan +
of_set_vlan_pcp (rte_flow) and "tx_vlan set pvid" already let you set
the priority bits today, with no new code.

If you still want "tx_vlan set" itself to carry priority, I'd suggest
a smaller change: relax only the TX insert validators and drop the
option and the global.  Don't touch rx_vft_set -- it feeds the VLAN
filter, which only takes a VLAN ID and rejects > 4095 anyway, so the
flag just turns a clear error into a confusing one.

Either way, if the option stays, please document it, and add a release note.
The commit message why the existing paths aren't enough.