On Thu, Nov 13, 2025 at 08:18:30AM +0000, Loktionov, Aleksandr wrote:
>
>
> > -----Original Message-----
> > From: [email protected] <[email protected]>
> > Sent: Thursday, November 13, 2025 9:05 AM
> > To: Loktionov, Aleksandr <[email protected]>; Nguyen,
> > Anthony L <[email protected]>; Kitszel, Przemyslaw
> > <[email protected]>; [email protected];
> > [email protected]; [email protected]; [email protected];
> > [email protected]
> > Cc: [email protected]; [email protected]; linux-
> > [email protected]; Gregory Herrero <[email protected]>
> > Subject: [PATCH v2 1/1] i40e: validate ring_len parameter against
> > hardware-specific values.
> >
> Please drop the trailing period from the subject.
>
Ok
> > From: Gregory Herrero <[email protected]>
> >
> > The maximum number of descriptors supported by the hardware is
> > hardware dependent and can be retrieved using
> > i40e_get_max_num_descriptors().
> > Move this function to a shared header and use it when checking for
> > valid ring_len parameter rather than using hardcoded value.
> > Cast info->ring_len to u32 in i40e_config_vsi_tx_queue() as it's u16
> > in struct virtchnl_txq_info.
> > Also cast it in i40e_config_vsi_rx_queue() even if it's u32 in
> > virtchnl_rxq_info to ease stable backport in case this changed.
> >
> > By fixing an over-acceptance issue, behavior change could be seen
> > where ring_len would now be rejected whereas it was not before.
> >
> Please add a short “Tested:” explanation (what hw/flows, expected/actual
> before/after).
>
No real test was done, it was found only by code inspection.
I could update the description though:
By fixing an over-acceptance issue, behavior change could be seen where
ring_len could now be rejected while configuring rx and tx queues if its
size is larger than the hardware-specific maximum number of descriptors.
> > Fixes: 55d225670def ("i40e: add validation for ring_len param")
> > Signed-off-by: Gregory Herrero <[email protected]>
> > ---
> > drivers/net/ethernet/intel/i40e/i40e.h | 17
> > +++++++++++++++++
> > drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 12 ------------
> > .../net/ethernet/intel/i40e/i40e_virtchnl_pf.c | 4 ++--
> > 3 files changed, 19 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/intel/i40e/i40e.h
> > b/drivers/net/ethernet/intel/i40e/i40e.h
> > index 801a57a925da..a953cce008f4 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e.h
> > +++ b/drivers/net/ethernet/intel/i40e/i40e.h
> > @@ -1418,4 +1418,21 @@ static inline struct i40e_veb
> > *i40e_pf_get_main_veb(struct i40e_pf *pf)
> > return (pf->lan_veb != I40E_NO_VEB) ? pf->veb[pf->lan_veb] :
> > NULL; }
> >
> > +/**
> > + * i40e_get_max_num_descriptors - get maximum number of descriptors
> > for this hardware.
> > + * @pf: pointer to a PF
> > + *
> > + * Return: u32 value corresponding to the maximum number of
> > descriptors.
> > + **/
> > +static inline u32 i40e_get_max_num_descriptors(const struct i40e_pf
> > +*pf) {
> > + const struct i40e_hw *hw = &pf->hw;
> > +
> > + switch (hw->mac.type) {
> > + case I40E_MAC_XL710:
> > + return I40E_MAX_NUM_DESCRIPTORS_XL710;
> > + default:
> > + return I40E_MAX_NUM_DESCRIPTORS;
> > + }
> > +}
> > #endif /* _I40E_H_ */
> > diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> > b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> > index 86c72596617a..61c39e881b00 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> > +++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> > @@ -2013,18 +2013,6 @@ static void i40e_get_drvinfo(struct net_device
> > *netdev,
> > drvinfo->n_priv_flags += I40E_GL_PRIV_FLAGS_STR_LEN; }
> >
> > -static u32 i40e_get_max_num_descriptors(struct i40e_pf *pf) -{
> > - struct i40e_hw *hw = &pf->hw;
> > -
> > - switch (hw->mac.type) {
> > - case I40E_MAC_XL710:
> > - return I40E_MAX_NUM_DESCRIPTORS_XL710;
> > - default:
> > - return I40E_MAX_NUM_DESCRIPTORS;
> > - }
> > -}
> > -
> > static void i40e_get_ringparam(struct net_device *netdev,
> > struct ethtool_ringparam *ring,
> > struct kernel_ethtool_ringparam
> > *kernel_ring, diff --git
> > a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
> > b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
> > index 081a4526a2f0..5e058159057b 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
> > +++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
> > @@ -656,7 +656,7 @@ static int i40e_config_vsi_tx_queue(struct i40e_vf
> > *vf, u16 vsi_id,
> >
> > /* ring_len has to be multiple of 8 */
> > if (!IS_ALIGNED(info->ring_len, 8) ||
> > - info->ring_len > I40E_MAX_NUM_DESCRIPTORS_XL710) {
> > + (u32)info->ring_len > i40e_get_max_num_descriptors(pf)) {
> > ret = -EINVAL;
> > goto error_context;
> > }
> > @@ -726,7 +726,7 @@ static int i40e_config_vsi_rx_queue(struct i40e_vf
> > *vf, u16 vsi_id,
> >
> > /* ring_len has to be multiple of 32 */
> > if (!IS_ALIGNED(info->ring_len, 32) ||
> > - info->ring_len > I40E_MAX_NUM_DESCRIPTORS_XL710) {
> > + (u32)info->ring_len > i40e_get_max_num_descriptors(pf)) {
> virtchnl_rxq_info.ring_len is already u32 (as noted in the commit message).
> Casting it to u32 before comparison is redundant and adds churn without value
> in mainline.
> The (u32) cast on info->ring_len can be dropped in mainline; if you need it
> only for a stable backport, consider keeping the mainline patch minimal and
> adding the backport‑only hunk when submitting to stable.
>
I've dropped this cast and removed the comment about it from the commit
description.
Thanks for the review,
Greg
