On 2/12/2024 3:19 AM, Michael S. Tsirkin wrote:
> On Fri, Feb 09, 2024 at 02:29:59PM -0800, Steve Sistare wrote:
>> Calling suspend or resume requires VIRTIO_CONFIG_S_DRIVER_OK, for all
>> vdpa devices.
>>
>> Suggested-by: Eugenio Perez Martin <eperezma@xxxxxxxxxx>"
>> Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
>
> I don't think failing suspend or resume makes sense though -
> e.g. practically failing suspend will just prevent sleeping I think -
> why should guest not having driver loaded prevent system suspend?
Got it, my fix is too heavy handed.
> there's also state such as features set which does need to be
> preserved.
>
> I think the thing to do is to skip invoking suspend/resume callback
OK.
> and in
> fact checking suspend/resume altogether.
Currently ops->suspend, vhost_vdpa_can_suspend(), and VHOST_BACKEND_F_SUSPEND
are equivalent. Hence if !ops->suspend, then then the driver does not support
it, and indeed may break if suspend is used, so system suspend must be blocked,
AFAICT. Yielding:
vhost_vdpa_suspend()
if (!ops->suspend)
return -EOPNOTSUPP;
if (!(ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK))
return 0;
- Steve
>> ---
>> drivers/vhost/vdpa.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>> index bc4a51e4638b..ce1882acfc3b 100644
>> --- a/drivers/vhost/vdpa.c
>> +++ b/drivers/vhost/vdpa.c
>> @@ -598,6 +598,9 @@ static long vhost_vdpa_suspend(struct vhost_vdpa *v)
>> if (!ops->suspend)
>> return -EOPNOTSUPP;
>>
>> + if (!(ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK))
>> + return -EINVAL;
>> +
>> ret = ops->suspend(vdpa);
>> if (!ret)
>> v->suspended = true;
>> @@ -618,6 +621,9 @@ static long vhost_vdpa_resume(struct vhost_vdpa *v)
>> if (!ops->resume)
>> return -EOPNOTSUPP;
>>
>> + if (!(ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK))
>> + return -EINVAL;
>> +
>> ret = ops->resume(vdpa);
>> if (!ret)
>> v->suspended = false;
>> --
>> 2.39.3
>
