Re: [dpdk-dev] [PATCH v4] ixgbe: Drop flow control frames from VFs

["Zhang, Helin" <helin.zhang@intel.com>]

> -----Original Message-----
> From: Vlad Zolotarov [mailto:vladz@cloudius-systems.com]
> Sent: Friday, October 23, 2015 5:00 PM
> To: Zhang, Helin
> Cc: Lu, Wenzhuo; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v4] ixgbe: Drop flow control frames from VFs
> 
> 
> 
> On 10/23/15 11:32, Zhang, Helin wrote:
> >
> >> -----Original Message-----
> >> From: Vlad Zolotarov [mailto:vladz@cloudius-systems.com]
> >> Sent: Friday, October 23, 2015 4:27 PM
> >> To: Zhang, Helin
> >> Cc: Lu, Wenzhuo; dev@dpdk.org
> >> Subject: Re: [dpdk-dev] [PATCH v4] ixgbe: Drop flow control frames
> >> from VFs
> >>
> >>
> >>
> >> On 10/23/15 10:14, Zhang, Helin wrote:
> >>> From: Vladislav Zolotarov [mailto:vladz@cloudius-systems.com]
> >>> Sent: Friday, October 23, 2015 2:57 PM
> >>> To: Zhang, Helin
> >>> Cc: Lu, Wenzhuo; dev@dpdk.org
> >>> Subject: RE: [dpdk-dev] [PATCH v4] ixgbe: Drop flow control frames
> >>> from VFs
> >>>
> >>>
> >>> On Oct 23, 2015 9:30 AM, "Zhang, Helin" <helin.zhang@intel.com> wrote:
> >>>>
> >>>> From: Vladislav Zolotarov [mailto:vladz@cloudius-systems.com]
> >>>> Sent: Friday, October 23, 2015 2:24 PM
> >>>> To: Zhang, Helin
> >>>> Cc: Lu, Wenzhuo; dev@dpdk.org
> >>>> Subject: Re: [dpdk-dev] [PATCH v4] ixgbe: Drop flow control frames
> >>>> from VFs
> >>>>
> >>>>
> >>>> On Oct 23, 2015 9:02 AM, "Zhang, Helin" <helin.zhang@intel.com> wrote:
> >>>>>
> >>>>>> -----Original Message-----
> >>>>>> From: Lu, Wenzhuo
> >>>>>> Sent: Friday, October 23, 2015 1:52 PM
> >>>>>> To: dev@dpdk.org
> >>>>>> Cc: Zhang, Helin; Lu, Wenzhuo
> >>>>>> Subject: [PATCH v4] ixgbe: Drop flow control frames from VFs
> >>>>>>
> >>>>>> This patch will drop flow control frames from being transmitted from
> VSIs.
> >>>>>> With this patch in place a malicious VF cannot send flow control
> >>>>>> or PFC packets out on the wire.
> >>>> The whole idea of this (and similar i40e patches sent before) is
> >>>> really
> >> confusing.
> >>>> If u want to disable FC feature for VFs then go and disable the
> >>>> feature. Why
> >> keep (not malicious) user think that he/she has enabled the feature
> >> while u silently block it?
> >>>> Helin: I don't think disabling FC is equal to filtering out any
> >>>> pause frames. How
> >> about the software application constructs a pause frame and then
> >> tries to send it out?
> >>> But not disabling FC for the user and silently preventing it is
> >>> bogus. First, the
> >> conventional user should not be affected. I think this patch (and all
> >> its clones) should be extended to, first, disable the FC Tx feature
> >> for the relevant devices and only then adding any anti malicious filtering.
> >>> Helin: Disabling FC will disable both PF and VF FC, I don't find out
> >>> where can
> >> disable VF FC only. Am I wrong?
> >>
> >> There are flow_ctrl_get/set callbacks in eth_dev_ops which are used
> >> for configuring FC.
> >> I see that they are not set for either ixgbevf or i40evf, so here we
> >> are all set for these.
> > Helin: The behaviors rely on the hardware capability, but not the SW.
> > I meant I don't think it can support disabling VF FC. Please correct me in case I
> am wrong!
> 
> I see. After a shallow sweep on the x540 and xl710 specs it seems that u r right.
> However I was talking about the SW interface only and since it is not enabled for
> the devices in question my whole objection is removed.
> 
> thanks,
> vlad

Vlad, thank you very much!
The best way for this issue is to do that in hardware, but now we need a fix/workaround.
It is really good to have the discussion with you, and clarify a lot. I think it can also remove a lot of questions from others. Thank you!

Regards,
Helin

> 
> >
> >
> >>>>>> V2:
> >>>>>> Reword the comments.
> >>>>>>
> >>>>>> V3:
> >>>>>> Move the check of set_ethertype_anti_spoofing to the top of the
> >>>>>> function,
> >> to
> >>>>>> avoid occupying an ethertype_filter entity without using it.
> >>>>>>
> >>>>>> V4:
> >>>>>> Remove the useless braces and return.
> >>>>>>
> >>>>>> Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
> >>>>> Acked-by: Helin Zhang <helin.zhang@intel.com>
> >>>>>