Commit 46030379 authored by Harald Freudenberger's avatar Harald Freudenberger Committed by Heiko Carstens
Browse files

s390/ap: Restrict driver_override versus apmask and aqmask use 



Introduce a restriction for the driver_override feature versus apmask
and aqmask:
- driver_override is only allowed when the apmask and aqmask values
  both are default (=0xffff..ffff).
- apmask and aqmask modifications are only allowed when there is no
  driver_override on any AP device active.
So in the end the user is restricted to choose to either use
apmask/apmask to divide the AP devices into host owned and vfio owned
or use the driver_override feature but not mix these two approaches.

Signed-off-by: default avatarHarald Freudenberger <freude@linux.ibm.com>
Reviewed-by: default avatarHolger Dengler <dengler@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
parent 8babcc2b

drivers/s390/crypto/ap_bus.c

+34 −3
Original line number Diff line number Diff line
@@ -86,8 +86,13 @@ DEFINE_SPINLOCK(ap_queues_lock); 
/* Default permissions (ioctl, card and domain masking) */

struct ap_perms ap_perms;

EXPORT_SYMBOL(ap_perms);

/* true if apmask and/or aqmask are NOT default */

bool ap_apmask_aqmask_in_use;

/* counter for how many driver_overrides are currently active */

int ap_driver_override_ctr;

/*

 * Mutex for consistent read and write of the ap_perms struct

 * Mutex for consistent read and write of the ap_perms struct,

 * ap_apmask_aqmask_in_use, ap_driver_override_ctr

 * and the ap bus sysfs attributes apmask and aqmask.

 */

DEFINE_MUTEX(ap_attr_mutex);
@@ -1542,18 +1547,31 @@ static int apmask_commit(unsigned long *newapm) 


	memcpy(ap_perms.apm, newapm, APMASKSIZE);



	/*

	 * Update ap_apmask_aqmask_in_use. Note that the

	 * ap_attr_mutex has to be obtained here.

	 */

	ap_apmask_aqmask_in_use =

		bitmap_full(ap_perms.apm, AP_DEVICES) &&

		bitmap_full(ap_perms.aqm, AP_DOMAINS) ?

		false : true;



	return 0;

}



static ssize_t apmask_store(const struct bus_type *bus, const char *buf,

			    size_t count)

{

	int rc, changes = 0;

	DECLARE_BITMAP(newapm, AP_DEVICES);

	int rc = -EINVAL, changes = 0;



	if (mutex_lock_interruptible(&ap_attr_mutex))

		return -ERESTARTSYS;



	/* Do not allow apmask/aqmask if driver override is active */

	if (ap_driver_override_ctr)

		goto done;



	rc = ap_parse_bitmap_str(buf, ap_perms.apm, AP_DEVICES, newapm);

	if (rc)

		goto done;
@@ -1636,18 +1654,31 @@ static int aqmask_commit(unsigned long *newaqm) 


	memcpy(ap_perms.aqm, newaqm, AQMASKSIZE);



	/*

	 * Update ap_apmask_aqmask_in_use. Note that the

	 * ap_attr_mutex has to be obtained here.

	 */

	ap_apmask_aqmask_in_use =

		bitmap_full(ap_perms.apm, AP_DEVICES) &&

		bitmap_full(ap_perms.aqm, AP_DOMAINS) ?

		false : true;



	return 0;

}



static ssize_t aqmask_store(const struct bus_type *bus, const char *buf,

			    size_t count)

{

	int rc, changes = 0;

	DECLARE_BITMAP(newaqm, AP_DOMAINS);

	int rc = -EINVAL, changes = 0;



	if (mutex_lock_interruptible(&ap_attr_mutex))

		return -ERESTARTSYS;



	/* Do not allow apmask/aqmask if driver override is active */

	if (ap_driver_override_ctr)

		goto done;



	rc = ap_parse_bitmap_str(buf, ap_perms.aqm, AP_DOMAINS, newaqm);

	if (rc)

		goto done;

drivers/s390/crypto/ap_bus.h

+2 −0
Original line number Diff line number Diff line
@@ -281,6 +281,8 @@ struct ap_perms { 
};



extern struct ap_perms ap_perms;

extern bool ap_apmask_aqmask_in_use;

extern int ap_driver_override_ctr;

extern struct mutex ap_attr_mutex;



/*

drivers/s390/crypto/ap_queue.c

+20 −3
Original line number Diff line number Diff line
@@ -755,13 +755,30 @@ static ssize_t driver_override_store(struct device *dev, 
{

	struct ap_queue *aq = to_ap_queue(dev);

	struct ap_device *ap_dev = &aq->ap_dev;

	int rc;

	int rc = -EINVAL;

	bool old_value;



	if (mutex_lock_interruptible(&ap_attr_mutex))

		return -ERESTARTSYS;



	/* Do not allow driver override if apmask/aqmask is in use */

	if (ap_apmask_aqmask_in_use)

		goto out;



	old_value = ap_dev->driver_override ? true : false;

	rc = driver_set_override(dev, &ap_dev->driver_override, buf, count);

	if (rc)

		return rc;

		goto out;

	if (old_value && !ap_dev->driver_override)

		--ap_driver_override_ctr;

	else if (!old_value && ap_dev->driver_override)

		++ap_driver_override_ctr;



	return count;

	rc = count;



out:

	mutex_unlock(&ap_attr_mutex);

	return rc;

}



static DEVICE_ATTR_RW(driver_override);