Re: [PATCH net] igb: do not let a VF set other VMOLR bits through its frame size

[Paolo Abeni <pabeni@redhat.com>]

On 11/4/26 07:34, Tjerk Kusters via B4 Relay wrote:
> From: Tjerk Kusters <tkusters@aweta.nl>
> 
> igb_set_vf_rlpml() gets the maximum frame size from the VF's
> E1000_VF_SET_LPE mailbox message and takes it as a signed int. A value
> with bit 31 set is negative, so it passes the "size >
> MAX_JUMBO_FRAME_SIZE" clamp, and it is then ORed into the VF pool's
> VMOLR without masking. Its upper bits set other bits of that register,
> such as AUPE and ROPE.
> 
> A VF whose port VLAN was set by the PF has AUPE cleared, so that it only
> receives frames tagged with that VLAN. Through this message it can set
> AUPE again and receive untagged frames. It can also set ROPE, so that its
> pool accepts unicast frames that match the Unicast Table Array; while the
> PF fills that table, in promiscuous mode or when it has more unicast
> addresses than receive address registers, that is all unicast traffic.
> igb_set_vf_promisc() does not offer this to VFs.
> 
> Take the size as u32, so that such values are clamped to
> MAX_JUMBO_FRAME_SIZE, which fits in the RLPML field.
> 
> Tested on an I350 with two VFs and kernel 7.3.1. VF 0 got port VLAN 100,
> and a test build of igbvf sent its frame size with bits 31, 26 and 24
> set. Before this patch, AUPE, ROPE and STRCRC were then set in that VF
> pool's VMOLR (0x8f010bce); with it they stay clear, and the size is
> clamped to 9728. The normal igbvf still sets its size (3022 at VF MTU
> 3000) as before.
> 
> This was found by the Sashiko AI review of another igb patch.
> 
> Link: https://lore.kernel.org/all/179370458190.488856.17697539789438631896@kernel.org/
> Fixes: 4ae196dfd61d ("igb: Add support for enabling VFs to PF driver.")
> Cc: stable@vger.kernel.org
> Signed-off-by: Tjerk Kusters <tkusters@aweta.nl>
I still assume this one will go via the intel tree first. Please LMK
if I should apply it directly, thanks!

Paolo