Re: [dpdk-dev] [PATCH v5 5/6] ixgbe: Config VF RSS

["Ouyang, Changchun" <changchun.ouyang@intel.com>]

> -----Original Message-----
> From: Vlad Zolotarov [mailto:vladz@cloudius-systems.com]
> Sent: Thursday, January 8, 2015 5:43 PM
> To: Ouyang, Changchun; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v5 5/6] ixgbe: Config VF RSS
> 
> 
> On 01/07/15 08:32, Ouyang Changchun wrote:
> > It needs config RSS and IXGBE_MRQC and IXGBE_VFPSRTYPE to enable VF
> RSS.
> >
> > The psrtype will determine how many queues the received packets will
> > distribute to, and the value of psrtype should depends on both facet:
> > max VF rxq number which has been negotiated with PF, and the number of
> rxq specified in config on guest.
> >
> > Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
> >
> > Changes in v4:
> >   - the number of rxq from config should be power of 2 and should not
> bigger than
> >      max VF rxq number(negotiated between guest and host).
> >
> > ---
> >   lib/librte_pmd_ixgbe/ixgbe_pf.c   |  15 ++++++
> >   lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 103
> +++++++++++++++++++++++++++++++++-----
> >   2 files changed, 106 insertions(+), 12 deletions(-)
> >
> > diff --git a/lib/librte_pmd_ixgbe/ixgbe_pf.c
> > b/lib/librte_pmd_ixgbe/ixgbe_pf.c index dbda9b5..93f6e43 100644
> > --- a/lib/librte_pmd_ixgbe/ixgbe_pf.c
> > +++ b/lib/librte_pmd_ixgbe/ixgbe_pf.c
> > @@ -187,6 +187,21 @@ int ixgbe_pf_host_configure(struct rte_eth_dev
> *eth_dev)
> >   	IXGBE_WRITE_REG(hw, IXGBE_MPSAR_LO(hw-
> >mac.num_rar_entries), 0);
> >   	IXGBE_WRITE_REG(hw, IXGBE_MPSAR_HI(hw-
> >mac.num_rar_entries), 0);
> >
> > +	/*
> > +	 * VF RSS can support at most 4 queues for each VF, even if
> > +	 * 8 queues are available for each VF, it need refine to 4
> > +	 * queues here due to this limitation, otherwise no queue
> > +	 * will receive any packet even RSS is enabled.
> > +	 */
> > +	if (eth_dev->data->dev_conf.rxmode.mq_mode ==
> ETH_MQ_RX_VMDQ_RSS) {
> > +		if (RTE_ETH_DEV_SRIOV(eth_dev).nb_q_per_pool == 8) {
> > +			RTE_ETH_DEV_SRIOV(eth_dev).active =
> ETH_32_POOLS;
> > +			RTE_ETH_DEV_SRIOV(eth_dev).nb_q_per_pool = 4;
> > +			RTE_ETH_DEV_SRIOV(eth_dev).def_pool_q_idx =
> > +				dev_num_vf(eth_dev) * 4;
> > +		}
> > +	}
> > +
> >   	/* set VMDq map to default PF pool */
> >   	hw->mac.ops.set_vmdq(hw, 0,
> > RTE_ETH_DEV_SRIOV(eth_dev).def_vmdq_idx);
> >
> > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > index f69abda..e83a9ab 100644
> > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c
> > @@ -3327,6 +3327,68 @@ ixgbe_alloc_rx_queue_mbufs(struct
> igb_rx_queue *rxq)
> >   }
> >
> >   static int
> > +ixgbe_config_vf_rss(struct rte_eth_dev *dev) {
> > +	struct ixgbe_hw *hw;
> > +	uint32_t mrqc;
> > +
> > +	ixgbe_rss_configure(dev);
> > +
> > +	hw = IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private);
> > +
> > +	/* MRQC: enable VF RSS */
> > +	mrqc = IXGBE_READ_REG(hw, IXGBE_MRQC);
> > +	mrqc &= ~IXGBE_MRQC_MRQE_MASK;
> > +	switch (RTE_ETH_DEV_SRIOV(dev).active) {
> > +	case ETH_64_POOLS:
> > +		mrqc |= IXGBE_MRQC_VMDQRSS64EN;
> 
> > +		break;
> > +
> > +	case ETH_32_POOLS:
> > +	case ETH_16_POOLS:
> 
> Isn't ETH_16_POOLS mode is invalid for VF RSS? It's what both spec states
> and what u handle in this patch in ixgbe_pf_host_configure().
> IMHO it would be better to treat this mode value as an error here since if u
> get it here it indicates of a SW bug.

I think we discussed it before already,  return err here will break here in the case of max vf number is less than 16.
If doing that, This make the library seems can't support vf rss in the case of max vf num less than 16.
So we obviously don't hope it break here.