s390/zcrypt: externalize test AP queue

Under certain specified conditions, the Test AP Queue (TAPQ)
subfunction of the Process Adjunct Processor Queue (PQAP) instruction
will be intercepted by a guest VM. The guest VM must have a means for
executing the intercepted instruction.

The vfio_ap driver will provide an interface to execute the
PQAP(TAPQ) instruction subfunction on behalf of a guest VM.
The code for executing the AP instructions currently resides in the
AP bus. This patch refactors the AP bus code to externalize access
to the PQAP(TAPQ) instruction subfunction to make it available to
the vfio_ap driver.

Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 22 insertions, 6 deletions

diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 6dee598979e7..4fcfa8d4e0b5 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -166,19 +166,33 @@ static int ap_configuration_available(void)
 }
 
 /**
+ * ap_apft_available(): Test if AP facilities test (APFT)
+ * facility is available.
+ *
+ * Returns 1 if APFT is is available.
+ */
+static int ap_apft_available(void)
+{
+	return test_facility(15);
+}
+
+/**
  * ap_test_queue(): Test adjunct processor queue.
  * @qid: The AP queue number
+ * @tbit: Test facilities bit
  * @info: Pointer to queue descriptor
  *
  * Returns AP queue status structure.
  */
-static inline struct ap_queue_status
-ap_test_queue(ap_qid_t qid, unsigned long *info)
+struct ap_queue_status ap_test_queue(ap_qid_t qid,
+				     int tbit,
+				     unsigned long *info)
 {
-	if (test_facility(15))
-		qid |= 1UL << 23;		/* set APFT T bit*/
+	if (tbit)
+		qid |= 1UL << 23; /* set T bit*/
 	return ap_tapq(qid, info);
 }
+EXPORT_SYMBOL(ap_test_queue);
 
 static inline int ap_query_configuration(void)
 {
@@ -261,7 +275,7 @@ static int ap_query_queue(ap_qid_t qid, int *queue_depth, int *device_type,
 	if (!ap_test_config_card_id(AP_QID_CARD(qid)))
 		return -ENODEV;
 
-	status = ap_test_queue(qid, &info);
+	status = ap_test_queue(qid, ap_apft_available(), &info);
 	switch (status.response_code) {
 	case AP_RESPONSE_NORMAL:
 		*queue_depth = (int)(info & 0xff);
@@ -940,7 +954,9 @@ static int ap_select_domain(void)
 		for (j = 0; j < AP_DEVICES; j++) {
 			if (!ap_test_config_card_id(j))
 				continue;
-			status = ap_test_queue(AP_MKQID(j, i), NULL);
+			status = ap_test_queue(AP_MKQID(j, i),
+					       ap_apft_available(),
+					       NULL);
 			if (status.response_code != AP_RESPONSE_NORMAL)
 				continue;
 			count++;