[dpdk-dev] [PATCH] net/ixgbevf: fix stats update after a PF reset

[Dai, Wei]

HI, Olivier

> 
> Hi Wei,
> 
> On Wed, 29 Mar 2017 09:22:55 +0000, "Dai, Wei" <wei.dai at intel.com> wrote:
> > First of all, I don't agree the method in this patch because the
> > register can also rewind to 0 in normal mode except reset/PF down.
> >
> > In the function void ixgbe_down(struct ixgbe_adapter *adapter) of
> > ixgbe_main.c in the ixgbe kernel PF driver (version 5.0.4), the PF in kernel
> driver will ping all the active vfs to let them know PF is going down by mailbox
> messages.
> >
> > On other side, ixgbe VF in DPDK PMD will handle the ping mailbox
> > message in ixgbevf_dev_interrupt_handler( ) which is registered interrupt
> routine.
> > And ixgbevf_dev_interrupt_handler( ) will call ixgbevf_mbx_process( ) to
> process mailbox message from PF.
> >
> > So it is in ixgbevf_mbx_process( ) where the SW stats registers of VF can be
> fixed.
> > There is more than one line to send ping message to VF in kernel PF drvier
> codes.
> 
> Thank you for the explanation.
> 
> Just to be sure I correctly understand:
> 1- the ping message is properly sent by ixgbe pf linux driver
Yes, I think so.

> 2- the ping message is not yet sent by ixgbe pf dpdk driver
I have not find any codes in DPDK PF to send them.

> 3- the ping message is properly received by ixgbe vf dpdk driver, but
>    it is not used yet to stop wrong stats accumulation
Yes, need register some callback function on to handle it.

> 
> > I am studying it to make it clear how to identify the ping message due to PF
> down.
> 
> Are you saying that you are currently working on a fix for 2 and 3 (that would be
> great!) or are you expecting that I work on it? In any case, I can help, at least
> to test the patches.

I am working on it now. Need check both ixgbe kernel driver and DPDK driver and also
need look up some pages in datasheet including 82599, X540 and X550.
So it is not an easy task.
By the way, not only statistics function but also other configurations should be 
restored.

Anyway, I always appreciate your help. Of course, you can help me test my upcoming patches.

Thanks 
-Wei

> 
> 
> > So can we defer this patch first.
> > And another patch in above way should be submitted.
> 
> 
> I'm of course ok to defer the initial patch, I agree it's more a workaround than a
> proper solution. I was stuck because I did not know how the VF is notified by
> the PF when it is reset.
> 
> 
> Thanks
> Olivier