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

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Date:   Tue, 14 Dec 2021 17:21:42 +0100
From:   Mikhail Golubev <mgo@...nsynergy.com>
To:     "Michael S. Tsirkin" <mst@...hat.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

The 12/13/2021 18:55, Michael S. Tsirkin wrote:
> 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.

Added ifdef CONFIG_PM_SLEEP in the patch v2 for simplicity and to be more
aligned with other PM code in drivers/virtio.

> 
> 
> >  
> > -- 
> > 2.34.1
> > 
> > 
> > -- 
> 

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