Mailing List Archive: [PATCH v10 04/17] vdpa: Fail the vdpa_reset() if fail to set device status to zero

[PATCH v10 04/17] vdpa: Fail the vdpa_reset() if fail to set device status to zero

Jul 29, 2021, 1:05 AM

Post #1 of 4 (14 views)

Re-read the device status to ensure it's set to zero during
resetting. Otherwise, fail the vdpa_reset() after timeout.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
include/linux/vdpa.h | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 406d53a606ac..d1a80ef05089 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -6,6 +6,7 @@
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/vhost_iotlb.h>
+#include <linux/delay.h>

/**
* struct vdpa_calllback - vDPA callback definition.
@@ -340,12 +341,24 @@ static inline struct device *vdpa_get_dma_dev(struct vdpa_device *vdev)
return vdev->dma_dev;
}

-static inline void vdpa_reset(struct vdpa_device *vdev)
+#define VDPA_RESET_TIMEOUT_MS 1000
+
+static inline int vdpa_reset(struct vdpa_device *vdev)
{
const struct vdpa_config_ops *ops = vdev->config;
+ int timeout = 0;

vdev->features_valid = false;
ops->set_status(vdev, 0);
+ while (ops->get_status(vdev)) {
+ timeout += 20;
+ if (timeout > VDPA_RESET_TIMEOUT_MS)
+ return -EIO;
+
+ msleep(20);
+ }
+
+ return 0;
}

static inline int vdpa_set_features(struct vdpa_device *vdev, u64 features)
--
2.11.0

Re: [PATCH v10 04/17] vdpa: Fail the vdpa_reset() if fail to set device status to zero [ In reply to ]

jasowang at redhat

Aug 3, 2021, 1:05 AM

Post #2 of 4 (14 views)

Permalink

?? 2021/7/29 ????3:34, Xie Yongji ???:
> Re-read the device status to ensure it's set to zero during
> resetting. Otherwise, fail the vdpa_reset() after timeout.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> ---
> include/linux/vdpa.h | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index 406d53a606ac..d1a80ef05089 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -6,6 +6,7 @@
> #include <linux/device.h>
> #include <linux/interrupt.h>
> #include <linux/vhost_iotlb.h>
> +#include <linux/delay.h>
>
> /**
> * struct vdpa_calllback - vDPA callback definition.
> @@ -340,12 +341,24 @@ static inline struct device *vdpa_get_dma_dev(struct vdpa_device *vdev)
> return vdev->dma_dev;
> }
>
> -static inline void vdpa_reset(struct vdpa_device *vdev)
> +#define VDPA_RESET_TIMEOUT_MS 1000
> +
> +static inline int vdpa_reset(struct vdpa_device *vdev)
> {
> const struct vdpa_config_ops *ops = vdev->config;
> + int timeout = 0;
>
> vdev->features_valid = false;
> ops->set_status(vdev, 0);
> + while (ops->get_status(vdev)) {
> + timeout += 20;
> + if (timeout > VDPA_RESET_TIMEOUT_MS)
> + return -EIO;
> +
> + msleep(20);
> + }

I wonder if it's better to do this in the vDPA parent?

Thanks

> +
> + return 0;
> }
>
> static inline int vdpa_set_features(struct vdpa_device *vdev, u64 features)

Re: [PATCH v10 04/17] vdpa: Fail the vdpa_reset() if fail to set device status to zero [ In reply to ]

xieyongji at bytedance

Aug 3, 2021, 4:15 AM

Post #3 of 4 (14 views)

Permalink

On Tue, Aug 3, 2021 at 3:58 PM Jason Wang <jasowang@redhat.com> wrote:
>
>
> ? 2021/7/29 ??3:34, Xie Yongji ??:
> > Re-read the device status to ensure it's set to zero during
> > resetting. Otherwise, fail the vdpa_reset() after timeout.
> >
> > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > ---
> > include/linux/vdpa.h | 15 ++++++++++++++-
> > 1 file changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> > index 406d53a606ac..d1a80ef05089 100644
> > --- a/include/linux/vdpa.h
> > +++ b/include/linux/vdpa.h
> > @@ -6,6 +6,7 @@
> > #include <linux/device.h>
> > #include <linux/interrupt.h>
> > #include <linux/vhost_iotlb.h>
> > +#include <linux/delay.h>
> >
> > /**
> > * struct vdpa_calllback - vDPA callback definition.
> > @@ -340,12 +341,24 @@ static inline struct device *vdpa_get_dma_dev(struct vdpa_device *vdev)
> > return vdev->dma_dev;
> > }
> >
> > -static inline void vdpa_reset(struct vdpa_device *vdev)
> > +#define VDPA_RESET_TIMEOUT_MS 1000
> > +
> > +static inline int vdpa_reset(struct vdpa_device *vdev)
> > {
> > const struct vdpa_config_ops *ops = vdev->config;
> > + int timeout = 0;
> >
> > vdev->features_valid = false;
> > ops->set_status(vdev, 0);
> > + while (ops->get_status(vdev)) {
> > + timeout += 20;
> > + if (timeout > VDPA_RESET_TIMEOUT_MS)
> > + return -EIO;
> > +
> > + msleep(20);
> > + }
>
>
> I wonder if it's better to do this in the vDPA parent?
>
> Thanks
>

Sorry, I didn't get you here. Do you mean vDPA parent driver (e.g.
VDUSE)? Actually I didn't find any other place where I can do
set_status() and get_status().

Thanks,
Yongji

Re: [PATCH v10 04/17] vdpa: Fail the vdpa_reset() if fail to set device status to zero [ In reply to ]

jasowang at redhat

Aug 4, 2021, 2:15 AM

Post #4 of 4 (14 views)

Permalink

? 2021/8/3 ??5:31, Yongji Xie ??:
> On Tue, Aug 3, 2021 at 3:58 PM Jason Wang <jasowang@redhat.com> wrote:
>>
>> ? 2021/7/29 ??3:34, Xie Yongji ??:
>>> Re-read the device status to ensure it's set to zero during
>>> resetting. Otherwise, fail the vdpa_reset() after timeout.
>>>
>>> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
>>> ---
>>> include/linux/vdpa.h | 15 ++++++++++++++-
>>> 1 file changed, 14 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
>>> index 406d53a606ac..d1a80ef05089 100644
>>> --- a/include/linux/vdpa.h
>>> +++ b/include/linux/vdpa.h
>>> @@ -6,6 +6,7 @@
>>> #include <linux/device.h>
>>> #include <linux/interrupt.h>
>>> #include <linux/vhost_iotlb.h>
>>> +#include <linux/delay.h>
>>>
>>> /**
>>> * struct vdpa_calllback - vDPA callback definition.
>>> @@ -340,12 +341,24 @@ static inline struct device *vdpa_get_dma_dev(struct vdpa_device *vdev)
>>> return vdev->dma_dev;
>>> }
>>>
>>> -static inline void vdpa_reset(struct vdpa_device *vdev)
>>> +#define VDPA_RESET_TIMEOUT_MS 1000
>>> +
>>> +static inline int vdpa_reset(struct vdpa_device *vdev)
>>> {
>>> const struct vdpa_config_ops *ops = vdev->config;
>>> + int timeout = 0;
>>>
>>> vdev->features_valid = false;
>>> ops->set_status(vdev, 0);
>>> + while (ops->get_status(vdev)) {
>>> + timeout += 20;
>>> + if (timeout > VDPA_RESET_TIMEOUT_MS)
>>> + return -EIO;
>>> +
>>> + msleep(20);
>>> + }
>>
>> I wonder if it's better to do this in the vDPA parent?
>>
>> Thanks
>>
> Sorry, I didn't get you here. Do you mean vDPA parent driver (e.g.
> VDUSE)?

Yes, since the how it's expected to behave depends on the specific hardware.

Even for the spec, the behavior is transport specific:

PCI: requires reread until 0
MMIO: doesn't require but it might not work for the hardware so we
decide to change
CCW: the succeed of the ccw command means the success of the reset

Thanks

> Actually I didn't find any other place where I can do
> set_status() and get_status().
>
> Thanks,
> Yongji
>