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s390/vfio-ap: No need to disable IRQ after queue reset

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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: Tony Krowiak <akrowiak@linux.ibm.com>
[pasic@linux.ibm.com: minor rework before merging]
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: ec89b55e3b ("s390: ap: implement PAPQ AQIC interception in kernel")
Cc: <stable@vger.kernel.org>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Tony Krowiak 2020-12-22 20:15:53 -05:00 • committed by Vasily Gorbik
parent f21916ec48
commit 6c12a6384e
3 changed files with 69 additions and 49 deletions
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6
drivers/s390/crypto/vfio_ap_drv.c
View file

@ -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);
}

100
drivers/s390/crypto/vfio_ap_ops.c
View file

@ -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->matrix_mdev = matrix_mdev;
put_device(dev);
q = vfio_ap_find_queue(apqn);
if (q)
q->matrix_mdev = matrix_mdev;
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;
q->saved_pfn = 0;
}
}
/**
@ -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 @@ notify_done:
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);
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;
case AP_RESPONSE_RESET_IN_PROGRESS:
case AP_RESPONSE_BUSY:
if (!q)
return 0;
retry_zapq:
status = ap_zapq(q->apqn);
switch (status.response_code) {
case AP_RESPONSE_NORMAL:
ret = 0;
break;
case AP_RESPONSE_RESET_IN_PROGRESS:
if (retry--) {
msleep(20);
break;
default:
/* things are really broken, give up */
return -EIO;
goto retry_zapq;
}
} while (retry--);
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;
}
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));
}
}

12
drivers/s390/crypto/vfio_ap_private.h
View file

@ -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_ */