Re: [Intel-wired-lan] [PATCH] i40e: validate ring_len parameter against hardware specific values.

[Gregory Herrero <gregory.herrero@oracle.com>]

On Fri, Nov 07, 2025 at 06:39:16AM +0000, Loktionov, Aleksandr wrote:
> 
> 
> > -----Original Message-----
> > From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf
> > Of gregory.herrero@oracle.com
> > Sent: Thursday, November 6, 2025 4:03 PM
> > To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel,
> > Przemyslaw <przemyslaw.kitszel@intel.com>; andrew+netdev@lunn.ch;
> > davem@davemloft.net; edumazet@google.com; kuba@kernel.org;
> > pabeni@redhat.com
> > Cc: intel-wired-lan@lists.osuosl.org; netdev@vger.kernel.org; linux-
> > kernel@vger.kernel.org; Gregory Herrero <gregory.herrero@oracle.com>
> > Subject: [Intel-wired-lan] [PATCH] i40e: validate ring_len parameter
> > against hardware specific values.
> “hardware specific” → “hardware‑specific”
> 
I will fix it in v2.
> >
> > From: Gregory Herrero <gregory.herrero@oracle.com>
> > 
> > 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.
> > 
> > Fixes: 55d225670def ("i40e: add validation for ring_len param")
> > Signed-off-by: Gregory Herrero <gregory.herrero@oracle.com>
> > ---
> >  drivers/net/ethernet/intel/i40e/i40e.h         | 18
> > ++++++++++++++++++
> >  drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 12 ------------
> > .../net/ethernet/intel/i40e/i40e_virtchnl_pf.c |  4 ++--
> >  3 files changed, 20 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/intel/i40e/i40e.h
> > b/drivers/net/ethernet/intel/i40e/i40e.h
> > index 801a57a925da..0e697375fcaf 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e.h
> > +++ b/drivers/net/ethernet/intel/i40e/i40e.h
> > @@ -1418,4 +1418,22 @@ 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 descriptors number for
> > this hardware.
> > + * @pf: pointer to a PF
> > + *
> > + * Return: u32 value corresponding to maximum descriptors number.
> > + **/
> “maximum descriptors number” → “maximum number of descriptors”
I will fix it in v2.

> " **/” → “ */
I followed coding style of the file. If I change from **/ to */, should
I change the whole file in a separate commit? Or should I keep as it is ?
> 
> 
> > +static inline u32 i40e_get_max_num_descriptors(struct i40e_pf *pf) {
> Nit: kernel coding style
> Please follow standard kernel style for function definitions:
> 
>  - The opening brace must be on its own line, not after the prototype.
It should already be the case. I double checked in the patch and on the mailing
list. Am I missing something?
>  - static inline is fine here, but keep spacing consistent.
Ah I missed that, which spacing is not consistent?
>  - Also consider marking the argument const if the function does not modify pf.
> 
> So instead of:
> static inline u32 i40e_get_max_num_descriptors(struct i40e_pf *pf) {
> use:
> static inline u32 i40e_get_max_num_descriptors(const struct i40e_pf *pf)
> {
> 
> See: https://docs.kernel.org/process/coding-style.html  section on function definitions.
Ok, I will fix it in v2.
> 
> > +	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)) {
> >  		ret = -EINVAL;
> >  		goto error_param;
> >  	}
> > --
> > 2.51.0
> 
> Behavior change / potential regression:
> This switches validation from a hard‑coded XL710 maximum to the per‑MAC maximum.
> That will tighten the limit on non‑XL710 controllers and can reject ring_len values that previously passed validation.
> Please call this out in the commit message so users understand the change (it fixes an over‑acceptance issue).
> 
I will add below comment in v2:
  By fixing an over-acceptance issue, behavior change could be seen where
  ring_len would now be rejected whereas it was not before.

> Return codes / logging:
> -EINVAL is fine for invalid virtchnl parameters; please keep it silent (no dmesg) to avoid log spam from misconfigured VFs.
> 
I didn't add any extra log and I don't see any which would be printed
when this error happen. (I checked the callers)
I could be missing something though.

Thanks for the review!
I will wait for your answers before sending v2.

Gregory