From 01396a374c3d31bc5f8b693026cfa9a657319624 Mon Sep 17 00:00:00 2001 From: Harald Freudenberger Date: Fri, 22 Feb 2019 17:24:11 +0100 Subject: s390/zcrypt: revisit ap device remove procedure Working with the vfio-ap driver let to some revisit of the way how an ap (queue) device is removed from the driver. With the current implementation all the cleanup was done before the driver even got notified about the removal. Now the ap queue removal is done in 3 steps: 1) A preparation step, all ap messages within the queue are flushed and so the driver does 'receive' them. Also a new state AP_STATE_REMOVE assigned to the queue makes sure there are no new messages queued in. 2) Now the driver's remove function is invoked and the driver should do the job of cleaning up it's internal administration lists or whatever. After 2) is done it is guaranteed, that the driver is not invoked any more. On the other hand the driver has to make sure that the APQN is not accessed any more after step 2 is complete. 3) Now the ap bus code does the job of total cleanup of the APQN. A reset with zero is triggered and the state of the queue goes to AP_STATE_UNBOUND. After step 3) is complete, the ap queue has no pending messages and the APQN is cleared and so there are no requests and replies lingering around in the firmware queue for this APQN. Also the interrupts are disabled. After these remove steps the ap queue device may be assigned to another driver. Stress testing this remove/probe procedure showed a problem with the correct module reference counting. The actual receive of an reply in the driver is done asynchronous with completions. So with a driver change on an ap queue the message flush triggers completions but the threads waiting for the completions may run at a time where the queue already has the new driver assigned. So the module_put() at receive time needs to be done on the driver module which queued the ap message. This change is also part of this patch. Signed-off-by: Harald Freudenberger Reviewed-by: Ingo Franzki Signed-off-by: Martin Schwidefsky --- drivers/s390/crypto/ap_bus.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers/s390/crypto/ap_bus.c') diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c index e15816ff1265..033a1acabf48 100644 --- a/drivers/s390/crypto/ap_bus.c +++ b/drivers/s390/crypto/ap_bus.c @@ -810,11 +810,18 @@ static int ap_device_remove(struct device *dev) struct ap_device *ap_dev = to_ap_dev(dev); struct ap_driver *ap_drv = ap_dev->drv; + /* prepare ap queue device removal */ if (is_queue_dev(dev)) - ap_queue_remove(to_ap_queue(dev)); + ap_queue_prepare_remove(to_ap_queue(dev)); + + /* driver's chance to clean up gracefully */ if (ap_drv->remove) ap_drv->remove(ap_dev); + /* now do the ap queue device remove */ + if (is_queue_dev(dev)) + ap_queue_remove(to_ap_queue(dev)); + /* Remove queue/card from list of active queues/cards */ spin_lock_bh(&ap_list_lock); if (is_card_dev(dev)) -- cgit From 0d9c038feff6f834ad9e5d88b66715235ab23ff3 Mon Sep 17 00:00:00 2001 From: Tony Krowiak Date: Mon, 18 Feb 2019 12:01:35 -0500 Subject: zcrypt: handle AP Info notification from CHSC SEI command The current AP bus implementation periodically polls the AP configuration to detect changes. When the AP configuration is dynamically changed via the SE or an SCLP instruction, the changes will not be reflected to sysfs until the next time the AP configuration is polled. The CHSC architecture provides a Store Event Information (SEI) command to make notification of an AP configuration change. This patch introduces a handler to process notification from the CHSC SEI command by immediately kicking off an AP bus scan-after-event. Signed-off-by: Tony Krowiak Reviewed-by: Halil Pasic Reviewed-by: Sebastian Ott Reviewed-by: Harald Freudenberger Reviewed-by: Cornelia Huck Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky --- drivers/s390/crypto/ap_bus.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'drivers/s390/crypto/ap_bus.c') diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c index 033a1acabf48..1546389d71db 100644 --- a/drivers/s390/crypto/ap_bus.c +++ b/drivers/s390/crypto/ap_bus.c @@ -867,6 +867,16 @@ void ap_bus_force_rescan(void) } EXPORT_SYMBOL(ap_bus_force_rescan); +/* +* A config change has happened, force an ap bus rescan. +*/ +void ap_bus_cfg_chg(void) +{ + AP_DBF(DBF_INFO, "%s config change, forcing bus rescan\n", __func__); + + ap_bus_force_rescan(); +} + /* * hex2bitmap() - parse hex mask string and set bitmap. * Valid strings are "0x012345678" with at least one valid hex number. -- cgit