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Subject: Re: [PATCH v2 2/2] vfio/fsl-mc: Add per device reset support
To:     Diana Craciun <diana.craciun@oss.nxp.com>,
        linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org,
        Alex Williamson <alex.williamson@redhat.com>,
        kvm@vger.kernel.org
Cc:     Li Yang <leoyang.li@nxp.com>, linux-arm-kernel@lists.infradead.org
References: <20210922110530.24736-1-diana.craciun@oss.nxp.com>
 <20210922110530.24736-2-diana.craciun@oss.nxp.com>
From:   Laurentiu Tudor <laurentiu.tudor@nxp.com>
Message-ID: <e356b582-7911-6c8e-3201-dbfdbd3e3b1d@nxp.com>
Date:   Tue, 28 Sep 2021 16:55:06 +0300
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On 9/22/2021 2:05 PM, Diana Craciun wrote:
> Currently when a fsl-mc device is reset, the entire DPRC container
> is reset which is very inefficient because the devices within a
> container will be reset multiple times.
> Add support for individually resetting a device.
> 
> Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
> ---

Reviewed-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>

---
Best Regards, Laurentiu

>  drivers/vfio/fsl-mc/vfio_fsl_mc.c | 45 ++++++++++++++++++++-----------
>  1 file changed, 30 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> index 0ead91bfa838..6d7b2d2571a2 100644
> --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> @@ -65,6 +65,34 @@ static void vfio_fsl_mc_regions_cleanup(struct vfio_fsl_mc_device *vdev)
>  	kfree(vdev->regions);
>  }
>  
> +static int vfio_fsl_mc_reset_device(struct vfio_fsl_mc_device *vdev)
> +{
> +	struct fsl_mc_device *mc_dev = vdev->mc_dev;
> +	int ret = 0;
> +
> +	if (is_fsl_mc_bus_dprc(vdev->mc_dev)) {
> +		return dprc_reset_container(mc_dev->mc_io, 0,
> +					mc_dev->mc_handle,
> +					mc_dev->obj_desc.id,
> +					DPRC_RESET_OPTION_NON_RECURSIVE);
> +	} else {
> +		u16 token;
> +
> +		ret = fsl_mc_obj_open(mc_dev->mc_io, 0, mc_dev->obj_desc.id,
> +				      mc_dev->obj_desc.type,
> +				      &token);
> +		if (ret)
> +			goto out;
> +		ret = fsl_mc_obj_reset(mc_dev->mc_io, 0, token);
> +		if (ret) {
> +			fsl_mc_obj_close(mc_dev->mc_io, 0, token);
> +			goto out;
> +		}
> +		ret = fsl_mc_obj_close(mc_dev->mc_io, 0, token);
> +	}
> +out:
> +	return ret;
> +}
>  
>  static void vfio_fsl_mc_close_device(struct vfio_device *core_vdev)
>  {
> @@ -78,9 +106,7 @@ static void vfio_fsl_mc_close_device(struct vfio_device *core_vdev)
>  	vfio_fsl_mc_regions_cleanup(vdev);
>  
>  	/* reset the device before cleaning up the interrupts */
> -	ret = dprc_reset_container(mc_cont->mc_io, 0, mc_cont->mc_handle,
> -				   mc_cont->obj_desc.id,
> -				   DPRC_RESET_OPTION_NON_RECURSIVE);
> +	ret = vfio_fsl_mc_reset_device(vdev);
>  
>  	if (WARN_ON(ret))
>  		dev_warn(&mc_cont->dev,
> @@ -203,18 +229,7 @@ static long vfio_fsl_mc_ioctl(struct vfio_device *core_vdev,
>  	}
>  	case VFIO_DEVICE_RESET:
>  	{
> -		int ret;
> -		struct fsl_mc_device *mc_dev = vdev->mc_dev;
> -
> -		/* reset is supported only for the DPRC */
> -		if (!is_fsl_mc_bus_dprc(mc_dev))
> -			return -ENOTTY;
> -
> -		ret = dprc_reset_container(mc_dev->mc_io, 0,
> -					   mc_dev->mc_handle,
> -					   mc_dev->obj_desc.id,
> -					   DPRC_RESET_OPTION_NON_RECURSIVE);
> -		return ret;
> +		return vfio_fsl_mc_reset_device(vdev);
>  
>  	}
>  	default:
>