linux-kernel - Re: [PATCH] virtio_mmio: pm: Add notification handlers for restore and freeze

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Date:   Mon, 13 Dec 2021 18:55:44 -0500
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     Mikhail Golubev <Mikhail.Golubev@...nsynergy.com>
Cc:     virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org, Jason Wang <jasowang@...hat.com>
Subject: Re: [PATCH] virtio_mmio: pm: Add notification handlers for restore
 and freeze

On Mon, Dec 13, 2021 at 05:00:08PM +0100, Mikhail Golubev wrote:
> From: Yurii Danilovskyi <glyd@...nsynergy.com>
> 
> Handle restore and freeze notifications from the PM core. Expose
> these to individual virtio drivers that can quiesce and resume vq
> operations.
> 
> Signed-off-by: Yurii Danilovskyi <glyd@...nsynergy.com>
> Signed-off-by: Mikhail Golubev <Mikhail.Golubev@...nsynergy.com>
> ---
>  drivers/virtio/virtio_mmio.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 56128b9c46eb..af79f8c2a2f2 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -762,6 +762,24 @@ static void vm_unregister_cmdline_devices(void)
>  
>  #endif
>  
> +static int __maybe_unused virtio_mmio_freeze(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
> +
> +	return virtio_device_freeze(&vm_dev->vdev);
> +}
> +
> +static int __maybe_unused virtio_mmio_restore(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
> +
> +	return virtio_device_restore(&vm_dev->vdev);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(virtio_mmio_pm_ops, virtio_mmio_freeze, virtio_mmio_restore);
> +
>  /* Platform driver */
>  
>  static const struct of_device_id virtio_mmio_match[] = {
> @@ -785,6 +803,7 @@ static struct platform_driver virtio_mmio_driver = {
>  		.name	= "virtio-mmio",
>  		.of_match_table	= virtio_mmio_match,
>  		.acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
> +		.pm = &virtio_mmio_pm_ops,
>  	},
>  };

All this code needs to be within ifdef CONFIG_PM_SLEEP.  Alternatively,
tweak virtio.h to expose virtio_device_freeze/virtio_device_restore
unconditionally.


>  
> -- 
> 2.34.1
> 
> 
> --