On Thu, 27 Aug 2020 10:24:07 -0400 Tony Krowiak <[email protected]> wrote:
> On 8/25/20 6:13 AM, Cornelia Huck wrote: > > On Fri, 21 Aug 2020 15:56:02 -0400 > > Tony Krowiak<[email protected]> wrote: > >> /** > >> - * vfio_ap_get_queue: Retrieve a queue with a specific APQN from a list > >> - * @matrix_mdev: the associated mediated matrix > >> + * 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 of the vfio_ap_drv. > >> - * Verify that the APID and the APQI are set in the matrix. > >> + * Retrieve a queue with a specific APQN from the AP queue devices > >> attached to > >> + * the AP bus. > >> * > >> - * Returns the pointer to the associated vfio_ap_queue > >> + * Returns the pointer to the vfio_ap_queue with the specified APQN, or > >> NULL. > >> */ > >> -static struct vfio_ap_queue *vfio_ap_get_queue( > >> - struct ap_matrix_mdev *matrix_mdev, > >> - int apqn) > >> +static struct vfio_ap_queue *vfio_ap_get_queue(unsigned long apqn) > >> { > >> + struct ap_queue *queue; > >> struct vfio_ap_queue *q; > >> - struct device *dev; > >> > >> - if (!test_bit_inv(AP_QID_CARD(apqn), matrix_mdev->matrix.apm)) > >> - return NULL; > >> - if (!test_bit_inv(AP_QID_QUEUE(apqn), matrix_mdev->matrix.aqm)) > > I think you should add some explanation to the patch description why > > testing the matrix bitmasks is not needed anymore. > > As a result of this comment, I took a closer look at the code to > determine the reason for eliminating the matrix_mdev > parameter. The reason is because the code below (i.e., find the device > and get the driver data) was also repeated in the vfio_ap_irq_disable_apqn() > function, so I replaced it with a call to the function above; however, the > vfio_ap_irq_disable_apqn() function does not have a reference to the > matrix_mdev, so I eliminated the matrix_mdev parameter. Note that the > vfio_ap_irq_disable_apqn() is called for each APQN assigned to a matrix > mdev, so there is no need to test the bitmasks there. > > The other place from which the function above is called is > the handle_pqap() function which does have a reference to the > matrix_mdev. In order to ensure the integrity of the instruction > being intercepted - i.e., PQAP(AQIC) enable/disable IRQ for aN > AP queue - the testing of the matrix bitmasks probably ought to > be performed, so it will be done there instead of in the > vfio_ap_get_queue() function above. Should you add a comment that vfio_ap_get_queue() assumes that the caller makes sure that this is only called for APQNs that are assigned to a matrix? > > > > + queue = ap_get_qdev(apqn); > > + if (!queue) > > return NULL; > > > > - dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL, > > - &apqn, match_apqn); > > - if (!dev) > > - return NULL; > > - q = dev_get_drvdata(dev); > > - q->matrix_mdev = matrix_mdev; > > - put_device(dev); > > + q = dev_get_drvdata(&queue->ap_dev.device); > > + put_device(&queue->ap_dev.device); > > > > return q; > > } > > (...) > > >
