[dpdk-stable] [PATCH v3] net/ixgbe: fix configuration of max frame size

[Zhang, AlvinX]

Hi Guojia,
Thanks for you reply.

I will modify as we discussion.

> -----Original Message-----
> From: Guo, Jia <jia.guo at intel.com>
> Sent: Friday, January 15, 2021 4:15 PM
> To: Zhang, AlvinX <alvinx.zhang at intel.com>; Wang, Haiyue
> <haiyue.wang at intel.com>; Xie, WeiX <weix.xie at intel.com>
> Cc: dev at dpdk.org; Zhang, AlvinX <alvinx.zhang at intel.com>; stable at dpdk.org
> Subject: RE: [PATCH v3] net/ixgbe: fix configuration of max frame size
> 
> Hi, Alvin
> 
> > -----Original Message-----
> > From: Zhang,Alvin <alvinx.zhang at intel.com>
> > Sent: Friday, January 15, 2021 3:00 PM
> > To: Guo, Jia <jia.guo at intel.com>; Wang, Haiyue
> > <haiyue.wang at intel.com>; Xie, WeiX <weix.xie at intel.com>
> > Cc: dev at dpdk.org; Zhang, AlvinX <alvinx.zhang at intel.com>;
> > stable at dpdk.org
> > Subject: [PATCH v3] net/ixgbe: fix configuration of max frame size
> >
> > From: Alvin Zhang <alvinx.zhang at intel.com>
> >
> > For 82599 NIC, jumbo frame feature is not supported in IOV mode, but
> > if a VF requests to configure the frame size to that not bigger than
> > RTE_ETHER_MAX_LEN, the PMD should not return -1.
> > This patch keeps ixgbe PMD's handling mode consistent with kernel
> > driver in above situation.
> >
> 
> Why it should not return -1 and what is the kernel driver behaviors related with
> this patch?
> 
> > In addition, the value set by the command IXGBE_VF_SET_LPE represents
> > the max frame size, not the mtu.
> >
> > Fixes: 1b9ea09c067b ("ixgbe: support X550")
> > Fixes: 95a27b3ba5f5 ("net/ixgbe: enable jumbo frame for VF")
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Alvin Zhang <alvinx.zhang at intel.com>
> > ---
> >
> > V3: Restore variable name from cur_frame_size to max_frs.
> > ---
> >  drivers/net/ixgbe/ixgbe_pf.c | 17 ++++++++++-------
> >  1 file changed, 10 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/net/ixgbe/ixgbe_pf.c
> > b/drivers/net/ixgbe/ixgbe_pf.c index 833863a..1ffde56 100644
> > --- a/drivers/net/ixgbe/ixgbe_pf.c
> > +++ b/drivers/net/ixgbe/ixgbe_pf.c
> > @@ -555,17 +555,20 @@ int ixgbe_pf_host_configure(struct rte_eth_dev
> > *eth_dev)  ixgbe_set_vf_lpe(struct rte_eth_dev *dev, __rte_unused
> > uint32_t vf, uint32_t *msgbuf)  {  struct ixgbe_hw *hw =
> > IXGBE_DEV_PRIVATE_TO_HW(dev->data-
> > >dev_private);
> > -uint32_t new_mtu = msgbuf[1];
> > +uint32_t max_frame = msgbuf[1];
> >  uint32_t max_frs;
> >  uint32_t hlreg0;
> > -int max_frame = new_mtu + RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN;
> >
> >  /* X540 and X550 support jumbo frames in IOV mode */  if
> > (hw->mac.type != ixgbe_mac_X540 &&  hw->mac.type != ixgbe_mac_X550
> &&
> > hw->mac.type != ixgbe_mac_X550EM_x &&
> > -hw->mac.type != ixgbe_mac_X550EM_a)
> > -return -1;
> > +hw->mac.type != ixgbe_mac_X550EM_a) {
> > +if (max_frame > dev->data-
> > >dev_conf.rxmode.max_rx_pkt_len)
> 
> This condition is only for X540/X550?
> 
> > +return -1;
> > +
> > +return 0;
> > +}
> >
> 
> Assume that return 0 means success to set vf lpe, return -1 means failed to set vf
> lpe. If it is not support in VF, why return 0?
> 
> >  if (max_frame < RTE_ETHER_MIN_LEN ||
> >  max_frame >
> > RTE_ETHER_MAX_JUMBO_FRAME_LEN) @@ -573,9 +576,9 @@ int
> > ixgbe_pf_host_configure(struct rte_eth_dev *eth_dev)
> >
> >  max_frs = (IXGBE_READ_REG(hw, IXGBE_MAXFRS) &
> >     IXGBE_MHADD_MFS_MASK) >>
> > IXGBE_MHADD_MFS_SHIFT;
> > -if (max_frs < new_mtu) {
> > +if (max_frs < max_frame) {
> >  hlreg0 = IXGBE_READ_REG(hw, IXGBE_HLREG0); -if (new_mtu >
> > RTE_ETHER_MAX_LEN) {
> > +if (max_frame > RTE_ETHER_MAX_LEN) {
> >  dev->data->dev_conf.rxmode.offloads |=
> DEV_RX_OFFLOAD_JUMBO_FRAME;
> >  hlreg0 |= IXGBE_HLREG0_JUMBOEN;
> > @@ -586,7 +589,7 @@ int ixgbe_pf_host_configure(struct rte_eth_dev
> > *eth_dev)
> >  }
> >  IXGBE_WRITE_REG(hw, IXGBE_HLREG0, hlreg0);
> >
> > -max_frs = new_mtu << IXGBE_MHADD_MFS_SHIFT;
> > +max_frs = max_frame << IXGBE_MHADD_MFS_SHIFT;
> >  IXGBE_WRITE_REG(hw, IXGBE_MAXFRS, max_frs);  }
> >
> > --
> > 1.8.3.1
>