Hi,
On 05/29/2018 07:15 PM, Geert Uytterhoeven wrote:
> If a device is part of a PM Domain (e.g. power and/or clock domain), its
> power state is managed using Runtime PM. Without Runtime PM, the device
> may not be powered up or clocked, causing subtle failures, crashes, or
> system lock-ups when the device is accessed by the guest.
>
> Fix this by adding Runtime PM support, powering the device when the VFIO
> device is opened by the guest.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Reviewed-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
Acked-by: Eric Auger <eric.auger@xxxxxxxxxx>
Thanks
Eric
> ---
> Against linux-vfio/next
>
> v4:
> - Keep device powered while issuing reset,
>
> v3:
> - Drop controversial note about unsafeness of exporting fine-grained
> power management from host to guest,
>
> v2:
> - Improve wording,
> - Add Reviewed-by.
> ---
> drivers/vfio/platform/vfio_platform_common.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> index b60bb5326668498c..c0cd824be2b767be 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -17,6 +17,7 @@
> #include <linux/iommu.h>
> #include <linux/module.h>
> #include <linux/mutex.h>
> +#include <linux/pm_runtime.h>
> #include <linux/slab.h>
> #include <linux/types.h>
> #include <linux/uaccess.h>
> @@ -239,6 +240,7 @@ static void vfio_platform_release(void *device_data)
> ret, extra_dbg ? extra_dbg : "");
> WARN_ON(1);
> }
> + pm_runtime_put(vdev->device);
> vfio_platform_regions_cleanup(vdev);
> vfio_platform_irq_cleanup(vdev);
> }
> @@ -269,6 +271,10 @@ static int vfio_platform_open(void *device_data)
> if (ret)
> goto err_irq;
>
> + ret = pm_runtime_get_sync(vdev->device);
> + if (ret < 0)
> + goto err_pm;
> +
> ret = vfio_platform_call_reset(vdev, &extra_dbg);
> if (ret && vdev->reset_required) {
> dev_warn(vdev->device, "reset driver is required and reset call failed in open (%d) %s\n",
> @@ -283,6 +289,8 @@ static int vfio_platform_open(void *device_data)
> return 0;
>
> err_rst:
> + pm_runtime_put(vdev->device);
> +err_pm:
> vfio_platform_irq_cleanup(vdev);
> err_irq:
> vfio_platform_regions_cleanup(vdev);
> @@ -690,6 +698,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
>
> mutex_init(&vdev->igate);
>
> + pm_runtime_enable(vdev->device);
> return 0;
>
> put_iommu:
> @@ -707,6 +716,7 @@ struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
> vdev = vfio_del_group_dev(dev);
>
> if (vdev) {
> + pm_runtime_disable(vdev->device);
> vfio_platform_put_reset(vdev);
> vfio_iommu_group_put(dev->iommu_group, dev);
> }
>
