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, 64 insertions, 0 deletions

diff --git a/arch/s390/include/asm/ap.h b/arch/s390/include/asm/ap.h
new file mode 100644
index 000000000000..0f3e6f38db55
--- /dev/null
+++ b/arch/s390/include/asm/ap.h
@@ -0,0 +1,64 @@
+/*
+ * Adjunct processor (AP) interfaces
+ *
+ * Copyright IBM Corp. 2017
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ * Author(s): Tony Krowiak <akrowia@linux.vnet.ibm.com>
+ *	      Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *	      Harald Freudenberger <freude@de.ibm.com>
+ */
+
+#ifndef _ASM_S390_AP_H_
+#define _ASM_S390_AP_H_
+
+/**
+ * The ap_qid_t identifier of an ap queue.
+ * If the AP facilities test (APFT) facility is available,
+ * card and queue index are 8 bit values, otherwise
+ * card index is 6 bit and queue index a 4 bit value.
+ */
+typedef unsigned int ap_qid_t;
+
+#define AP_MKQID(_card, _queue) (((_card) & 63) << 8 | ((_queue) & 255))
+#define AP_QID_CARD(_qid) (((_qid) >> 8) & 63)
+#define AP_QID_QUEUE(_qid) ((_qid) & 255)
+
+/**
+ * struct ap_queue_status - Holds the AP queue status.
+ * @queue_empty: Shows if queue is empty
+ * @replies_waiting: Waiting replies
+ * @queue_full: Is 1 if the queue is full
+ * @irq_enabled: Shows if interrupts are enabled for the AP
+ * @response_code: Holds the 8 bit response code
+ *
+ * The ap queue status word is returned by all three AP functions
+ * (PQAP, NQAP and DQAP).  There's a set of flags in the first
+ * byte, followed by a 1 byte response code.
+ */
+struct ap_queue_status {
+	unsigned int queue_empty	: 1;
+	unsigned int replies_waiting	: 1;
+	unsigned int queue_full		: 1;
+	unsigned int _pad1		: 4;
+	unsigned int irq_enabled	: 1;
+	unsigned int response_code	: 8;
+	unsigned int _pad2		: 16;
+};
+
+/**
+ * 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.
+ */
+struct ap_queue_status ap_test_queue(ap_qid_t qid,
+				     int tbit,
+				     unsigned long *info);
+
+#endif /* _ASM_S390_AP_H_ */