Re: [PATCH v3 4/9] s390: ap: tools to find a queue with a specific APQN

[Pierre Morel]

On 15/02/2019 10:49, Cornelia Huck wrote:
> On Thu, 14 Feb 2019 14:51:04 +0100
> Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
>
> > We need to find the queue with a specific APQN during the
> > handling of the interception of the PQAP/AQIC instruction.
> >
> > To handle the AP associated device reference count we keep
> > track of it in the vfio_ap_queue until we put the device.
>
> So, the relationship is
> (struct ap_device)--(driver_data)-->(struct vfio_ap_queue)--(pointer)-->(struct ap_device)
> ? IOW, a backlink?
>
> If so, can't you already set that up during probe?

Will do.

> Or am I confused by the various similar devices again? Maybe a diagram
> would help...

No you are right.


> > Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
> > ---
> >   drivers/s390/crypto/vfio_ap_ops.c     | 54 +++++++++++++++++++++++++++++++++++
> >   drivers/s390/crypto/vfio_ap_private.h |  1 +
> >   2 files changed, 55 insertions(+)
> >
> > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> > index 900b9cf..2a52c9b 100644
> > --- a/drivers/s390/crypto/vfio_ap_ops.c
> > +++ b/drivers/s390/crypto/vfio_ap_ops.c
> > @@ -24,6 +24,60 @@
> >   #define VFIO_AP_MDEV_TYPE_HWVIRT "passthrough"
> >   #define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device"
> >   
> > +/**
> > + * vfio_ap_check_apqn: check if a ap_queue is of a given APQN
> > + *
> > + * Returns 1 if we have a match.
> > + * Otherwise returns 0.
> > + */
> > +static int vfio_ap_check_apqn(struct device *dev, void *data)
> > +{
> > +	struct vfio_ap_queue *q = dev_get_drvdata(dev);
> > +
> > +	return (q->apqn == *(int *)data);
> > +}
> > +
> > +/**
> > + * vfio_ap_get_queue: Retrieve a queue with a specific APQN
> > + * @apqn: The queue APQN
> > + *
> > + * Retrieve a queue with a specific APQN from the list of the
> > + * devices associated to the vfio_ap_driver.
> > + *
> > + * The vfio_ap_queue has been already associated with the device
> > + * during the probe.
> > + * Store the associated device for reference counting
> > + *
> > + * Returns the pointer to the associated vfio_ap_queue
> > + */
> > +static  __attribute__((unused))
>
> Eww. Can you get rid of that by reordering or squashing patches?

I did this to avoid posting a very big patch.
I will of course squash 4 and 5 with patch 6, when the two patches 4 and 
5 are reviewed.

If you think it brings more clarity to squash all for the next iteration 
I will do.

Regards,
Pierre


--
Pierre Morel
Linux/KVM/QEMU in BÃblingen - Germany