vfio: ccw: introduce channel program interfaces

Introduce ccwchain structure and helper functions that can be used to
handle a channel program issued from a virtual machine.

The following limitations apply:
1. Supports only prefetch enabled mode.
2. Supports idal(c64) ccw chaining.
3. Supports 4k idaw.
4. Supports ccw1.
5. Supports direct ccw chaining by translating them to idal ccws.

CCW translation requires to leverage the vfio_(un)pin_pages interfaces
to pin/unpin sets of mem pages frequently. Currently we have a lack of
support to do this in an efficient way. So we introduce pfn_array data
structure and helper functions to handle pin/unpin operations here.
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Message-Id: <20170317031743.40128-6-bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

drivers/s390/cio/Makefile

@@ -18,5 +18,5 @@ obj-$(CONFIG_CCWGROUP) += ccwgroup.o
 qdio-objs := qdio_main.o qdio_thinint.o qdio_debug.o qdio_setup.o
 obj-$(CONFIG_QDIO) += qdio.o
 
-vfio_ccw-objs += vfio_ccw_drv.o
+vfio_ccw-objs += vfio_ccw_drv.o vfio_ccw_cp.o
 obj-$(CONFIG_VFIO_CCW) += vfio_ccw.o

drivers/s390/cio/vfio_ccw_cp.h

+/*
+ * channel program interfaces
+ *
+ * Copyright IBM Corp. 2017
+ *
+ * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
+ *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
+ */
+
+#ifndef _VFIO_CCW_CP_H_
+#define _VFIO_CCW_CP_H_
+
+#include <asm/cio.h>
+#include <asm/scsw.h>
+
+#include "orb.h"
+
+/**
+ * struct channel_program - manage information for channel program
+ * @ccwchain_list: list head of ccwchains
+ * @orb: orb for the currently processed ssch request
+ * @mdev: the mediated device to perform page pinning/unpinning
+ *
+ * @ccwchain_list is the head of a ccwchain list, that contents the
+ * translated result of the guest channel program that pointed out by
+ * the iova parameter when calling cp_init.
+ */
+struct channel_program {
+	struct list_head ccwchain_list;
+	union orb orb;
+	struct device *mdev;
+};
+
+extern int cp_init(struct channel_program *cp, struct device *mdev,
+		   union orb *orb);
+extern void cp_free(struct channel_program *cp);
+extern int cp_prefetch(struct channel_program *cp);
+extern union orb *cp_get_orb(struct channel_program *cp, u32 intparm, u8 lpm);
+extern void cp_update_scsw(struct channel_program *cp, union scsw *scsw);
+extern bool cp_iova_pinned(struct channel_program *cp, u64 iova);
+
+#endif