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Date: Sun, 4 Feb 2024 13:20:44 +0200
From: Leon Romanovsky <leon@kernel.org>
To: Emily Deng <Emily.Deng@amd.com>
Cc: amd-gfx@lists.freedesktop.org, bhelgaas@google.com,
	alex.williamson@redhat.com, linux-pci@vger.kernel.org,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH] PCI: Add vf reset notification for pf
Message-ID: <20240204112044.GC5400@unreal>
References: <20240204061257.1408243-1-Emily.Deng@amd.com>
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In-Reply-To: <20240204061257.1408243-1-Emily.Deng@amd.com>

On Sun, Feb 04, 2024 at 02:12:57PM +0800, Emily Deng wrote:
> When a vf has been reset, the pf wants to get notification to remove the vf
> out of schedule.

It is very questionable if this is right thing to do. The idea of SR-IOV
is that VFs represent a physical device and they should be treated
separately from the PF.

In addition to that Keith said, this patch needs better justification.

Thanks

> 
> Solution:
> Add the callback function in pci_driver sriov_vf_reset_notification. When
> vf reset happens, then call this callback function.
> 
> Signed-off-by: Emily Deng <Emily.Deng@amd.com>
> ---
>  drivers/pci/pci.c   | 8 ++++++++
>  include/linux/pci.h | 1 +
>  2 files changed, 9 insertions(+)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 60230da957e0..aca937b05531 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4780,6 +4780,14 @@ EXPORT_SYMBOL_GPL(pcie_flr);
>   */
>  int pcie_reset_flr(struct pci_dev *dev, bool probe)
>  {
> +	struct pci_dev *pf_dev;
> +
> +	if (dev->is_virtfn) {
> +		pf_dev = dev->physfn;
> +		if (pf_dev->driver->sriov_vf_reset_notification)
> +			pf_dev->driver->sriov_vf_reset_notification(pf_dev, dev);
> +	}
> +
>  	if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
>  		return -ENOTTY;
>  
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index c69a2cc1f412..4fa31d9b0aa7 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -926,6 +926,7 @@ struct pci_driver {
>  	int  (*sriov_configure)(struct pci_dev *dev, int num_vfs); /* On PF */
>  	int  (*sriov_set_msix_vec_count)(struct pci_dev *vf, int msix_vec_count); /* On PF */
>  	u32  (*sriov_get_vf_total_msix)(struct pci_dev *pf);
> +	void  (*sriov_vf_reset_notification)(struct pci_dev *pf, struct pci_dev *vf);
>  	const struct pci_error_handlers *err_handler;
>  	const struct attribute_group **groups;
>  	const struct attribute_group **dev_groups;
> -- 
> 2.36.1
> 
>