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Date: Mon, 5 Feb 2024 11:04:38 +0200
From: Leon Romanovsky <leon@kernel.org>
To: Emily Deng <Emily.Deng@amd.com>
Cc: bhelgaas@google.com, alex.williamson@redhat.com,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, Jerry.Jiang@amd.com, Andy.Zhang@amd.com,
	HaiJun.Chang@amd.com, Monk.Liu@amd.com, Horace.Chen@amd.com,
	ZhenGuo.Yin@amd.com
Subject: Re: [PATCH 1/2] PCI: Add VF reset notification to PF's VFIO user
 mode driver
Message-ID: <20240205090438.GB6294@unreal>
References: <20240205071538.2665628-1-Emily.Deng@amd.com>
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In-Reply-To: <20240205071538.2665628-1-Emily.Deng@amd.com>

On Mon, Feb 05, 2024 at 03:15:37PM +0800, Emily Deng wrote:
> VF doesn't have the ability to reset itself completely which will cause the
> hardware in unstable state. So notify PF driver when the VF has been reset
> to let the PF resets the VF completely, and remove the VF out of schedule.


I'm sorry but this explanation is not different from the previous
version. Please provide a better explanation of the problem, why it is
needed, which VFs need and can't reset themselves, how and why it worked
before e.t.c.

In addition, please follow kernel submission guidelines, write
changelong, add versions, cover letter e.t.c.

Thanks

> 
> How to implement this?
> Add the reset callback function in pci_driver
> 
> Implement the callback functin in VFIO_PCI driver.
> 
> Add the VF RESET IRQ for user mode driver to let the user mode driver
> know the VF has been reset.
> 
> 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
> 
>