Commit a0d8f4ee authored by Tony Krowiak's avatar Tony Krowiak Committed by Alexander Gordeev
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s390/vfio-ap: fix sysfs status attribute for AP queue devices 



The 'status' attribute for AP queue devices bound to the vfio_ap device
driver displays incorrect status when the mediated device is attached to a
guest, but the queue device is not passed through. In the current
implementation, the status displayed is 'in_use' which is not correct; it
should be 'assigned'. This can happen if one of the queue devices
associated with a given adapter is not bound to the vfio_ap device driver.
For example:

Queues listed in /sys/bus/ap/drivers/vfio_ap:
14.0005
14.0006
14.000d
16.0006
16.000d

Queues listed in /sys/devices/vfio_ap/matrix/$UUID/matrix
14.0005
14.0006
14.000d
16.0005
16.0006
16.000d

Queues listed in /sys/devices/vfio_ap/matrix/$UUID/guest_matrix
14.0005
14.0006
14.000d

The reason no queues for adapter 0x16 are listed in the guest_matrix is
because queue 16.0005 is not bound to the vfio_ap device driver, so no
queue associated with the adapter is passed through to the guest;
therefore, each queue device for adapter 0x16 should display 'assigned'
instead of 'in_use', because those queues are not in use by a guest, but
only assigned to the mediated device.

Let's check the AP configuration for the guest to determine whether a
queue device is passed through before displaying a status of 'in_use'.

Signed-off-by: default avatarTony Krowiak <akrowiak@linux.ibm.com>
Acked-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Acked-by: default avatarHarald Freudenberger <freude@linux.ibm.com>
Link: https://lore.kernel.org/r/20231108201135.351419-1-akrowiak@linux.ibm.com


Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent c44ce579

drivers/s390/crypto/vfio_ap_ops.c

+15 −1
Original line number Diff line number Diff line
@@ -1980,6 +1980,7 @@ static ssize_t status_show(struct device *dev, 
{

	ssize_t nchars = 0;

	struct vfio_ap_queue *q;

	unsigned long apid, apqi;

	struct ap_matrix_mdev *matrix_mdev;

	struct ap_device *apdev = to_ap_dev(dev);
@@ -1987,8 +1988,21 @@ static ssize_t status_show(struct device *dev, 
	q = dev_get_drvdata(&apdev->device);

	matrix_mdev = vfio_ap_mdev_for_queue(q);



	/* If the queue is assigned to the matrix mediated device, then

	 * determine whether it is passed through to a guest; otherwise,

	 * indicate that it is unassigned.

	 */

	if (matrix_mdev) {

		if (matrix_mdev->kvm)

		apid = AP_QID_CARD(q->apqn);

		apqi = AP_QID_QUEUE(q->apqn);

		/*

		 * If the queue is passed through to the guest, then indicate

		 * that it is in use; otherwise, indicate that it is

		 * merely assigned to a matrix mediated device.

		 */

		if (matrix_mdev->kvm &&

		    test_bit_inv(apid, matrix_mdev->shadow_apcb.apm) &&

		    test_bit_inv(apqi, matrix_mdev->shadow_apcb.aqm))

			nchars = scnprintf(buf, PAGE_SIZE, "%s\n",

					   AP_QUEUE_IN_USE);

		else