Re: [dpdk-dev] [PATCH] igb: fix crash with offload on 82575 chipset

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Mar 25, 2016 at 02:06:51PM +0000, Ananyev, Konstantin wrote:
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Olivier Matz
> > Sent: Friday, March 25, 2016 10:32 AM
> > To: dev@dpdk.org
> > Cc: Lu, Wenzhuo
> > Subject: [dpdk-dev] [PATCH] igb: fix crash with offload on 82575 chipset
> > 
> > On the 82575 chipset, there is a pool of global TX contexts instead of 2
> > per queues on 82576. See Table A-1 "Changes in Programming Interface
> > Relative to 82575" of Intel® 82576EB GbE Controller datasheet (*).
> > 
> > In the driver, the contexts are attributed to a TX queue: 0-1 for txq0,
> > 2-3 for txq1, and so on.
> > 
> > In igbe_set_xmit_ctx(), the variable ctx_curr contains the index of the
> > per-queue context (0 or 1), and ctx_idx contains the index to be given
> > to the hardware (0 to 7). The size of txq->ctx_cache[] is 2, and must
> > be indexed with ctx_curr to avoid an out-of-bound access.
> > 
> > Also, the index returned by what_advctx_update() is the per-queue
> > index (0 or 1), so we need to add txq->ctx_start before sending it
> > to the hardware.
> > 
> > (*) The datasheets says 16 global contexts, however the IDX fields in TX
> >     descriptors are 3 bits, which gives a total of 8 contexts. The
> >     driver assumes there are 8 contexts on 82575: 2 per queues, 4 txqs.
> > 
> > Fixes: 4c8db5f09a ("igb: enable TSO support")
> > Fixes: af75078fec ("first public release")
> > Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> 
> Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

Applied to dpdk-next-net/rel_16_04

/Bruce