Re: [Intel-wired-lan] [PATCH iwl-net v1] i40e: Restore VF MSI-X state during PCI reset

[Przemek Kitszel <przemyslaw.kitszel@intel.com>]

On 12/4/23 14:10, Andrii Staikov wrote:
> During a PCI FLR the MSI-X Enable flag in the VF PCI MSI-X capability
> register will be cleared. This can lead to issues when a VF is
> assigned to a VM because in these cases the VF driver receives no
> indication of the PF PCI error/reset and additionally it is incapable
> of restoring the cleared flag in the hypervisor configuration space
> without fully reinitializing the driver interrupt functionality.
> 
> Since the VF driver is unable to easily resolve this condition on its own,
> restore the VF MSI-X flag during the PF PCI reset handling.
> 
> Fixes: 19b7960b2da1 ("i40e: implement split PCI error reset handler")
> Co-developed-by: Karen Ostrowska <karen.ostrowska@intel.com>
> Signed-off-by: Karen Ostrowska <karen.ostrowska@intel.com>
> Co-developed-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
> Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
> Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
> Signed-off-by: Andrii Staikov <andrii.staikov@intel.com>
> ---
> v1 -> v2: Add reviewed-by tag

you forgot to change the title :P

> ---
>   drivers/net/ethernet/intel/i40e/i40e_main.c   |  2 ++
>   .../ethernet/intel/i40e/i40e_virtchnl_pf.c    | 24 +++++++++++++++++++
>   .../ethernet/intel/i40e/i40e_virtchnl_pf.h    |  1 +
>   3 files changed, 27 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
> index 7bb1f64833eb..7272d0227a55 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -16513,6 +16513,8 @@ static void i40e_pci_error_reset_done(struct pci_dev *pdev)
>   		return;
>   
>   	i40e_reset_and_rebuild(pf, false, false);
> +
> +	i40e_restore_all_vfs_msi_state(pdev);
>   }
>   
>   /**
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
> index 3f99eb198245..b3da4cdf9d10 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
> @@ -154,6 +154,30 @@ void i40e_vc_notify_reset(struct i40e_pf *pf)
>   			     (u8 *)&pfe, sizeof(struct virtchnl_pf_event));
>   }
>   
> +void i40e_restore_all_vfs_msi_state(struct pci_dev *pdev)
> +{
> +	u16 vf_id;
> +	u16 pos;
> +
> +	/* Continue only if this is a PF */
> +	if (!pdev->is_physfn)
> +		return;
> +
> +	if (!pci_num_vf(pdev))
> +		return;
> +
> +	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_SRIOV);
> +	if (pos) {

declaration should be here, then one blank line

> +		pci_read_config_word(pdev, pos + PCI_SRIOV_VF_DID, &vf_id);
> +		struct pci_dev *vf_dev = NULL;

normally you don't 0-init variables, which get overwritten
unconditionally prior to first use

but here case is different, just code get somehow wrong :P

> +		while ((vf_dev = pci_get_device(pdev->vendor, vf_id, NULL))) {

instead of NULL you should pass @vf_dev as 3rd param

> +			if (vf_dev->is_virtfn && vf_dev->physfn == pdev)
> +				pci_restore_msi_state(vf_dev);
> +			vf_dev = pci_get_device(pdev->vendor, vf_id, vf_dev);

and remove this line

> +		}
> +	}
> +}
> +
>   /**
>    * i40e_vc_notify_vf_reset
>    * @vf: pointer to the VF structure
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.h b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.h
> index 2ee0f8a23248..1ff879784563 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.h
> +++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.h
> @@ -137,6 +137,7 @@ int i40e_ndo_set_vf_spoofchk(struct net_device *netdev, int vf_id, bool enable);
>   
>   void i40e_vc_notify_link_state(struct i40e_pf *pf);
>   void i40e_vc_notify_reset(struct i40e_pf *pf);
> +void i40e_restore_all_vfs_msi_state(struct pci_dev *pdev);
>   int i40e_get_vf_stats(struct net_device *netdev, int vf_id,
>   		      struct ifla_vf_stats *vf_stats);
>   

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