Re: [PATCH] virtio_mmio: add suspend and resume calls for virtio_mmio devices

From: Michael S. Tsirkin
Date: Thu Aug 10 2023 - 15:45:51 EST


On Fri, Jul 28, 2023 at 12:31:27PM +0530, Anvesh Jain P wrote:
> Handle suspend and resume calls for virtio mmio devices from
> PM core. Expose these notifications to virtio drivers that can quiesce and
> resume vq operations. Update virtio pm ops to handle freeze& restore and
> suspend & resume callbacks separately.
>
> Signed-off-by: Anvesh Jain P <quic_ajainp@xxxxxxxxxxx>
> Signed-off-by: Venkata Rao Kakani <quic_vkakani@xxxxxxxxxxx>

okey but what is the motivation? does this addition of 200 LOC
achieve something new? what is the issue fixed here?


> ---
> drivers/virtio/virtio.c | 112 +++++++++++++++++++++++++++++++++++
> drivers/virtio/virtio_mmio.c | 50 +++++++++++++++-
> include/linux/virtio.h | 12 ++++
> 3 files changed, 173 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> index 3893dc29eb26..c6f25a267600 100644
> --- a/drivers/virtio/virtio.c
> +++ b/drivers/virtio/virtio.c
> @@ -551,6 +551,118 @@ int virtio_device_restore(struct virtio_device *dev)
> return ret;
> }
> EXPORT_SYMBOL_GPL(virtio_device_restore);
> +
> +int virtio_device_suspend(struct virtio_device *dev)
> +{
> + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
> +
> + virtio_config_disable(dev);
> +
> + dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
> +
> + if (drv && drv->suspend)
> + return drv->suspend(dev);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_device_suspend);
> +
> +int virtio_device_resume(struct virtio_device *dev)
> +{
> + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
> + int ret;
> +
> + if (drv && drv->resume) {
> + ret = drv->resume(dev);
> + if (ret)
> + goto err;
> +
> + if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
> + virtio_device_ready(dev);
> +
> + virtio_config_enable(dev);
> + }
> +
> + return 0;
> +err:
> + virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(virtio_device_resume);
> +
> +int virtio_device_suspend_late(struct virtio_device *dev)
> +{
> + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
> +
> + virtio_config_disable(dev);
> +
> + dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
> +
> + if (drv && drv->suspend_late)
> + return drv->suspend_late(dev);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_device_suspend_late);
> +
> +int virtio_device_resume_early(struct virtio_device *dev)
> +{
> + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
> + int ret;
> +
> + if (drv && drv->resume_early) {
> + ret = drv->resume_early(dev);
> + if (ret)
> + goto err;
> + if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
> + virtio_device_ready(dev);
> +
> + virtio_config_enable(dev);
> + }
> +
> + return 0;
> +err:
> + virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(virtio_device_resume_early);
> +
> +int virtio_device_suspend_noirq(struct virtio_device *dev)
> +{
> + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
> +
> + virtio_config_disable(dev);
> +
> + dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
> +
> + if (drv && drv->suspend_noirq)
> + return drv->suspend_noirq(dev);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(virtio_device_suspend_noirq);
> +
> +int virtio_device_resume_noirq(struct virtio_device *dev)
> +{
> + struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
> + int ret;
> +
> + if (drv && drv->resume_noirq) {
> + ret = drv->resume_noirq(dev);
> + if (ret)
> + goto err;
> + if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
> + virtio_device_ready(dev);
> +
> + virtio_config_enable(dev);
> + }
> +
> + return 0;
> +err:
> + virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(virtio_device_resume_noirq);
> #endif
>
> static int virtio_init(void)
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index a46a4a29e929..9385c7e65da9 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -596,9 +596,57 @@ static int virtio_mmio_restore(struct device *dev)
>
> return virtio_device_restore(&vm_dev->vdev);
> }
> +static int virtio_mmio_suspend(struct device *dev)
> +{
> + struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
> +
> + return virtio_device_suspend(&vm_dev->vdev);
> +}
> +
> +static int virtio_mmio_resume(struct device *dev)
> +{
> + struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
> +
> + return virtio_device_resume(&vm_dev->vdev);
> +}
> +
> +static int virtio_mmio_suspend_late(struct device *dev)
> +{
> + struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
> +
> + return virtio_device_suspend_late(&vm_dev->vdev);
> +}
> +
> +static int virtio_mmio_resume_early(struct device *dev)
> +{
> + struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
> +
> + return virtio_device_resume_early(&vm_dev->vdev);
> +}
> +
> +static int virtio_mmio_suspend_noirq(struct device *dev)
> +{
> + struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
> +
> + return virtio_device_suspend_noirq(&vm_dev->vdev);
> +}
> +
> +static int virtio_mmio_resume_noirq(struct device *dev)
> +{
> + struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
> +
> + return virtio_device_resume_noirq(&vm_dev->vdev);
> +}
>
> static const struct dev_pm_ops virtio_mmio_pm_ops = {
> - SET_SYSTEM_SLEEP_PM_OPS(virtio_mmio_freeze, virtio_mmio_restore)
> + .freeze = virtio_mmio_freeze,
> + .restore = virtio_mmio_restore,
> + .suspend = virtio_mmio_suspend,
> + .resume = virtio_mmio_resume,
> + .suspend_late = virtio_mmio_suspend_late,
> + .resume_early = virtio_mmio_resume_early,
> + .suspend_noirq = virtio_mmio_suspend_noirq,
> + .resume_noirq = virtio_mmio_resume_noirq,
> };
> #endif
>
> diff --git a/include/linux/virtio.h b/include/linux/virtio.h
> index de6041deee37..e88b321408e9 100644
> --- a/include/linux/virtio.h
> +++ b/include/linux/virtio.h
> @@ -145,6 +145,12 @@ void virtio_config_changed(struct virtio_device *dev);
> #ifdef CONFIG_PM_SLEEP
> int virtio_device_freeze(struct virtio_device *dev);
> int virtio_device_restore(struct virtio_device *dev);
> +int virtio_device_suspend(struct virtio_device *dev);
> +int virtio_device_resume(struct virtio_device *dev);
> +int virtio_device_suspend_late(struct virtio_device *dev);
> +int virtio_device_resume_early(struct virtio_device *dev);
> +int virtio_device_suspend_noirq(struct virtio_device *dev);
> +int virtio_device_resume_noirq(struct virtio_device *dev);
> #endif
> void virtio_reset_device(struct virtio_device *dev);
>
> @@ -187,6 +193,12 @@ struct virtio_driver {
> #ifdef CONFIG_PM
> int (*freeze)(struct virtio_device *dev);
> int (*restore)(struct virtio_device *dev);
> + int (*suspend)(struct virtio_device *dev);
> + int (*resume)(struct virtio_device *dev);
> + int (*suspend_late)(struct virtio_device *dev);
> + int (*resume_early)(struct virtio_device *dev);
> + int (*suspend_noirq)(struct virtio_device *dev);
> + int (*resume_noirq)(struct virtio_device *dev);
> #endif
> };
>
>
> base-commit: 3f01e9fed8454dcd89727016c3e5b2fbb8f8e50c
> --
> 2.17.1