Hi Eric,
On Mon, May 28, 2018 at 10:27 PM, Auger Eric <eric.auger@xxxxxxxxxx> wrote:
> On 05/28/2018 05:26 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>
>> ---
>> v3:
>> - Drop controversial note about unsafeness of exporting fine-grained
>> power management from host to guest,
> thanks ;-)
>
>>
>> v2:
>> - Improve wording,
>> - Add Reviewed-by.
>> ---
>> drivers/vfio/platform/vfio_platform_common.c | 9 +++++++++
>> 1 file changed, 9 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>> index b60bb5326668498c..41f862f055054543 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>
>> @@ -233,6 +234,8 @@ static void vfio_platform_release(void *device_data)
>> const char *extra_dbg = NULL;
>> int ret;
>>
>> + pm_runtime_put(vdev->device);
>
>> +
>> ret = vfio_platform_call_reset(vdev, &extra_dbg);
> While reading the code again, the reset is using the HW. Don't you want
> to call the get() before.
Thanks, you're right, it's safer to do the reset here first...
>> if (ret && vdev->reset_required) {
>> dev_warn(vdev->device, "reset driver is required and reset call failed in release (%d) %s\n",
>> @@ -275,6 +278,10 @@ static int vfio_platform_open(void *device_data)
>> ret, extra_dbg ? extra_dbg : "");
>> goto err_rst;
>> }
>> +
>> + ret = pm_runtime_get_sync(vdev->device);
... and to do the reset here last.
Will fix and send v4.
>> + if (ret < 0)
>> + goto err_rst;
>> }
>>
>> vdev->refcnt++;
>> @@ -690,6 +697,7 @@ 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 +715,7 @@ 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);
>> }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
