s390/ap: re-init AP queues on config on

On a state toggle from config off to config on and on the
state toggle from checkstop to not checkstop the queue's
internal states was set but the state machine was not
nudged. This did not care as on the first enqueue of a
request the state machine kick ran.

However, within an Secure Execution guest a queue is
only chosen by the scheduler when it has been bound.
But to bind a queue, it needs to run through the initial
states (reset, enable interrupts, ...). So this is like
a chicken-and-egg problem and the result was in fact
that a queue was unusable after a config off/on toggle.

With some slight rework of the handling of these states
now the new function _ap_queue_init_state() is called
which is the core of the ap_queue_init_state() function
but without locking handling. This has the benefit that
it can be called on all the places where a (re-)init
of the AP queue's state machine is needed.

Fixes: 2d72eaf036d2 ("s390/ap: implement SE AP bind, unbind and associate")
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

3 files changed, 18 insertions, 13 deletions

diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 339812efe822..d09e08b71cfb 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -1865,15 +1865,18 @@ static inline void ap_scan_domains(struct ap_card *ac)
 			}
 			/* get it and thus adjust reference counter */
 			get_device(dev);
-			if (decfg)
+			if (decfg) {
 				AP_DBF_INFO("%s(%d,%d) new (decfg) queue dev created\n",
 					    __func__, ac->id, dom);
-			else if (chkstop)
+			} else if (chkstop) {
 				AP_DBF_INFO("%s(%d,%d) new (chkstop) queue dev created\n",
 					    __func__, ac->id, dom);
-			else
+			} else {
+				/* nudge the queue's state machine */
+				ap_queue_init_state(aq);
 				AP_DBF_INFO("%s(%d,%d) new queue dev created\n",
 					    __func__, ac->id, dom);
+			}
 			goto put_dev_and_continue;
 		}
 		/* handle state changes on already existing queue device */
@@ -1895,10 +1898,8 @@ static inline void ap_scan_domains(struct ap_card *ac)
 		} else if (!chkstop && aq->chkstop) {
 			/* checkstop off */
 			aq->chkstop = false;
-			if (aq->dev_state > AP_DEV_STATE_UNINITIATED) {
-				aq->dev_state = AP_DEV_STATE_OPERATING;
-				aq->sm_state = AP_SM_STATE_RESET_START;
-			}
+			if (aq->dev_state > AP_DEV_STATE_UNINITIATED)
+				_ap_queue_init_state(aq);
 			spin_unlock_bh(&aq->lock);
 			AP_DBF_DBG("%s(%d,%d) queue dev checkstop off\n",
 				   __func__, ac->id, dom);
@@ -1922,10 +1923,8 @@ static inline void ap_scan_domains(struct ap_card *ac)
 		} else if (!decfg && !aq->config) {
 			/* config on this queue device */
 			aq->config = true;
-			if (aq->dev_state > AP_DEV_STATE_UNINITIATED) {
-				aq->dev_state = AP_DEV_STATE_OPERATING;
-				aq->sm_state = AP_SM_STATE_RESET_START;
-			}
+			if (aq->dev_state > AP_DEV_STATE_UNINITIATED)
+				_ap_queue_init_state(aq);
 			spin_unlock_bh(&aq->lock);
 			AP_DBF_DBG("%s(%d,%d) queue dev config on\n",
 				   __func__, ac->id, dom);
diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index be54b070c031..3e34912a6050 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -287,6 +287,7 @@ struct ap_queue *ap_queue_create(ap_qid_t qid, int device_type);
 void ap_queue_prepare_remove(struct ap_queue *aq);
 void ap_queue_remove(struct ap_queue *aq);
 void ap_queue_init_state(struct ap_queue *aq);
+void _ap_queue_init_state(struct ap_queue *aq);
 
 struct ap_card *ap_card_create(int id, int queue_depth, int raw_type,
 			       int comp_type, unsigned int functions, int ml);
diff --git a/drivers/s390/crypto/ap_queue.c b/drivers/s390/crypto/ap_queue.c
index 1336e632adc4..2943b2529d3a 100644
--- a/drivers/s390/crypto/ap_queue.c
+++ b/drivers/s390/crypto/ap_queue.c
@@ -1160,14 +1160,19 @@ void ap_queue_remove(struct ap_queue *aq)
 	spin_unlock_bh(&aq->lock);
 }
 
-void ap_queue_init_state(struct ap_queue *aq)
+void _ap_queue_init_state(struct ap_queue *aq)
 {
-	spin_lock_bh(&aq->lock);
 	aq->dev_state = AP_DEV_STATE_OPERATING;
 	aq->sm_state = AP_SM_STATE_RESET_START;
 	aq->last_err_rc = 0;
 	aq->assoc_idx = ASSOC_IDX_INVALID;
 	ap_wait(ap_sm_event(aq, AP_SM_EVENT_POLL));
+}
+
+void ap_queue_init_state(struct ap_queue *aq)
+{
+	spin_lock_bh(&aq->lock);
+	_ap_queue_init_state(aq);
 	spin_unlock_bh(&aq->lock);
 }
 EXPORT_SYMBOL(ap_queue_init_state);