Commit 6c12a638 authored by Tony Krowiak's avatar Tony Krowiak Committed by Vasily Gorbik
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s390/vfio-ap: No need to disable IRQ after queue reset 



The queues assigned to a matrix mediated device are currently reset when:

* The VFIO_DEVICE_RESET ioctl is invoked
* The mdev fd is closed by userspace (QEMU)
* The mdev is removed from sysfs.

Immediately after the reset of a queue, a call is made to disable
interrupts for the queue. This is entirely unnecessary because the reset of
a queue disables interrupts, so this will be removed.

Furthermore, vfio_ap_irq_disable() does an unconditional PQAP/AQIC which
can result in a specification exception (when the corresponding facility
is not available), so this is actually a bugfix.

Signed-off-by: default avatarTony Krowiak <akrowiak@linux.ibm.com>
[pasic@linux.ibm.com: minor rework before merging]
Signed-off-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Fixes: ec89b55e ("s390: ap: implement PAPQ AQIC interception in kernel")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent f21916ec

drivers/s390/crypto/vfio_ap_drv.c

+1 −5
Original line number Diff line number Diff line
@@ -71,15 +71,11 @@ static int vfio_ap_queue_dev_probe(struct ap_device *apdev) 
static void vfio_ap_queue_dev_remove(struct ap_device *apdev)

{

	struct vfio_ap_queue *q;

	int apid, apqi;



	mutex_lock(&matrix_dev->lock);

	q = dev_get_drvdata(&apdev->device);

	vfio_ap_mdev_reset_queue(q, 1);

	dev_set_drvdata(&apdev->device, NULL);

	apid = AP_QID_CARD(q->apqn);

	apqi = AP_QID_QUEUE(q->apqn);

	vfio_ap_mdev_reset_queue(apid, apqi, 1);

	vfio_ap_irq_disable(q);

	kfree(q);

	mutex_unlock(&matrix_dev->lock);

}

drivers/s390/crypto/vfio_ap_ops.c

+62 −38
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#define VFIO_AP_MDEV_NAME_HWVIRT "VFIO AP Passthrough Device"



static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev);

static struct vfio_ap_queue *vfio_ap_find_queue(int apqn);



static int match_apqn(struct device *dev, const void *data)

{
@@ -49,20 +50,15 @@ static struct vfio_ap_queue *vfio_ap_get_queue( 
					int apqn)

{

	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))

		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 = vfio_ap_find_queue(apqn);

	if (q)

		q->matrix_mdev = matrix_mdev;

	put_device(dev);



	return q;

}
@@ -119,13 +115,18 @@ static void vfio_ap_wait_for_irqclear(int apqn) 
 */

static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q)

{

	if (q->saved_isc != VFIO_AP_ISC_INVALID && q->matrix_mdev)

	if (!q)

		return;

	if (q->saved_isc != VFIO_AP_ISC_INVALID &&

	    !WARN_ON(!(q->matrix_mdev && q->matrix_mdev->kvm))) {

		kvm_s390_gisc_unregister(q->matrix_mdev->kvm, q->saved_isc);

	if (q->saved_pfn && q->matrix_mdev)

		q->saved_isc = VFIO_AP_ISC_INVALID;

	}

	if (q->saved_pfn && !WARN_ON(!q->matrix_mdev)) {

		vfio_unpin_pages(mdev_dev(q->matrix_mdev->mdev),

				 &q->saved_pfn, 1);

		q->saved_pfn = 0;

	q->saved_isc = VFIO_AP_ISC_INVALID;

	}

}



/**
@@ -144,7 +145,7 @@ static void vfio_ap_free_aqic_resources(struct vfio_ap_queue *q) 
 * Returns if ap_aqic function failed with invalid, deconfigured or

 * checkstopped AP.

 */

struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q)

static struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q)

{

	struct ap_qirq_ctrl aqic_gisa = {};

	struct ap_queue_status status;
@@ -1126,48 +1127,70 @@ static int vfio_ap_mdev_group_notifier(struct notifier_block *nb, 
	return notify_rc;

}



static void vfio_ap_irq_disable_apqn(int apqn)

static struct vfio_ap_queue *vfio_ap_find_queue(int apqn)

{

	struct device *dev;

	struct vfio_ap_queue *q;

	struct vfio_ap_queue *q = NULL;



	dev = driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL,

				 &apqn, match_apqn);

	if (dev) {

		q = dev_get_drvdata(dev);

		vfio_ap_irq_disable(q);

		put_device(dev);

	}



	return q;

}



int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,

int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,

			     unsigned int retry)

{

	struct ap_queue_status status;

	int ret;

	int retry2 = 2;

	int apqn = AP_MKQID(apid, apqi);



	do {

		status = ap_zapq(apqn);

	if (!q)

		return 0;



retry_zapq:

	status = ap_zapq(q->apqn);

	switch (status.response_code) {

	case AP_RESPONSE_NORMAL:

			while (!status.queue_empty && retry2--) {

				msleep(20);

				status = ap_tapq(apqn, NULL);

			}

			WARN_ON_ONCE(retry2 <= 0);

			return 0;

		ret = 0;

		break;

	case AP_RESPONSE_RESET_IN_PROGRESS:

		case AP_RESPONSE_BUSY:

		if (retry--) {

			msleep(20);

			goto retry_zapq;

		}

		ret = -EBUSY;

		break;

	case AP_RESPONSE_Q_NOT_AVAIL:

	case AP_RESPONSE_DECONFIGURED:

	case AP_RESPONSE_CHECKSTOPPED:

		WARN_ON_ONCE(status.irq_enabled);

		ret = -EBUSY;

		goto free_resources;

	default:

		/* things are really broken, give up */

		WARN(true, "PQAP/ZAPQ completed with invalid rc (%x)\n",

		     status.response_code);

		return -EIO;

	}

	} while (retry--);



	return -EBUSY;

	/* wait for the reset to take effect */

	while (retry2--) {

		if (status.queue_empty && !status.irq_enabled)

			break;

		msleep(20);

		status = ap_tapq(q->apqn, NULL);

	}

	WARN_ON_ONCE(retry2 <= 0);



free_resources:

	vfio_ap_free_aqic_resources(q);



	return ret;

}



static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev)
@@ -1175,13 +1198,15 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev) 
	int ret;

	int rc = 0;

	unsigned long apid, apqi;

	struct vfio_ap_queue *q;

	struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);



	for_each_set_bit_inv(apid, matrix_mdev->matrix.apm,

			     matrix_mdev->matrix.apm_max + 1) {

		for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm,

				     matrix_mdev->matrix.aqm_max + 1) {

			ret = vfio_ap_mdev_reset_queue(apid, apqi, 1);

			q = vfio_ap_find_queue(AP_MKQID(apid, apqi));

			ret = vfio_ap_mdev_reset_queue(q, 1);

			/*

			 * Regardless whether a queue turns out to be busy, or

			 * is not operational, we need to continue resetting
@@ -1189,7 +1214,6 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev) 
			 */

			if (ret)

				rc = ret;

			vfio_ap_irq_disable_apqn(AP_MKQID(apid, apqi));

		}

	}

drivers/s390/crypto/vfio_ap_private.h

+6 −6
Original line number Diff line number Diff line
@@ -88,11 +88,6 @@ struct ap_matrix_mdev { 
	struct mdev_device *mdev;

};



extern int vfio_ap_mdev_register(void);

extern void vfio_ap_mdev_unregister(void);

int vfio_ap_mdev_reset_queue(unsigned int apid, unsigned int apqi,

			     unsigned int retry);



struct vfio_ap_queue {

	struct ap_matrix_mdev *matrix_mdev;

	unsigned long saved_pfn;
@@ -100,5 +95,10 @@ struct vfio_ap_queue { 
#define VFIO_AP_ISC_INVALID 0xff

	unsigned char saved_isc;

};

struct ap_queue_status vfio_ap_irq_disable(struct vfio_ap_queue *q);



int vfio_ap_mdev_register(void);

void vfio_ap_mdev_unregister(void);

int vfio_ap_mdev_reset_queue(struct vfio_ap_queue *q,

			     unsigned int retry);



#endif /* _VFIO_AP_PRIVATE_H_ */