SLOF: virtio-scsi helper routines

* initialize/shutdown virtio-scsi device
* routine for sending scsi commands to virtio-scsi device

[ Modified to pass the whole virtio req/resp from forth
  to allow better handling of status and sense buffer
  -- BenH
]

Signed-off-by: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

5 files changed, 244 insertions, 1 deletions

diff --git a/lib/libvirtio/Makefile b/lib/libvirtio/Makefile
index 994a885..e61457f 100644
--- a/lib/libvirtio/Makefile
+++ b/lib/libvirtio/Makefile
@@ -22,7 +22,7 @@ TARGET = ../libvirtio.a
 
 all: $(TARGET)
 
-SRCS =  virtio.c virtio-blk.c p9.c virtio-9p.c
+SRCS =  virtio.c virtio-blk.c p9.c virtio-9p.c virtio-scsi.c
 
 OBJS = $(SRCS:%.c=%.o)
 
diff --git a/lib/libvirtio/virtio-scsi.c b/lib/libvirtio/virtio-scsi.c
new file mode 100644
index 0000000..dba0cff
--- /dev/null
+++ b/lib/libvirtio/virtio-scsi.c
@@ -0,0 +1,143 @@
+/******************************************************************************
+ * Copyright (c) 2012 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ *     IBM Corporation - initial implementation
+ *****************************************************************************/
+
+#include <stdio.h>
+#include <string.h>
+#include "virtio.h"
+#include "virtio-scsi.h"
+
+#define sync()  asm volatile (" sync \n" ::: "memory")
+
+int virtioscsi_send(struct virtio_device *dev,
+		    struct virtio_scsi_req_cmd *req,
+		    struct virtio_scsi_resp_cmd *resp,
+		    int is_read, void *buf, uint64_t buf_len)
+{
+        struct vring_desc *desc;
+        struct vring_desc *vq_desc;		/* Descriptor vring */
+        struct vring_avail *vq_avail;		/* "Available" vring */
+        struct vring_used *vq_used;		/* "Used" vring */
+
+        volatile uint16_t *current_used_idx;
+        uint16_t last_used_idx;
+        int id, i;
+        uint32_t vq_size;
+
+        int vq = VIRTIO_SCSI_REQUEST_VQ;
+
+        vq_size = virtio_get_qsize(dev, vq);
+        vq_desc = virtio_get_vring_desc(dev, vq);
+        vq_avail = virtio_get_vring_avail(dev, vq);
+        vq_used = virtio_get_vring_used(dev, vq);
+
+        last_used_idx = vq_used->idx;
+        current_used_idx = &vq_used->idx;
+
+        /* Determine descriptor index */
+        id = (vq_avail->idx * 3) % vq_size;
+
+        desc = &vq_desc[id];
+        desc->addr = (uint64_t)req;
+        desc->len = sizeof(*req);
+        desc->flags = VRING_DESC_F_NEXT;
+        desc->next = (id + 1) % vq_size;
+
+        /* Set up virtqueue descriptor for data */
+        desc = &vq_desc[(id + 1) % vq_size];
+        desc->addr = (uint64_t)resp;
+        desc->len = sizeof(*resp);
+        desc->flags = VRING_DESC_F_NEXT | VRING_DESC_F_WRITE;
+        desc->next = (id + 2) % vq_size;
+
+        if (buf && buf_len) {
+                /* Set up virtqueue descriptor for status */
+                desc = &vq_desc[(id + 2) % vq_size];
+                desc->addr = (uint64_t)buf;
+                desc->len = buf_len;
+                desc->flags = is_read ? VRING_DESC_F_WRITE : 0;
+                desc->next = 0;
+        } else
+                desc->flags &= ~VRING_DESC_F_NEXT;
+
+        vq_avail->ring[vq_avail->idx % vq_size] = id;
+        sync();
+        vq_avail->idx += 1;
+
+        /* Tell HV that the vq is ready */
+        virtio_queue_notify(dev, vq);
+
+        /* Wait for host to consume the descriptor */
+        i = 10000000;
+        while (*current_used_idx == last_used_idx && i-- > 0) {
+                // do something better
+                sync();
+        }
+
+        return 0;
+}
+
+/**
+ * Initialize virtio-block device.
+ * @param  dev  pointer to virtio device information
+ */
+int virtioscsi_init(struct virtio_device *dev)
+{
+        struct vring_avail *vq_avail;
+        unsigned int idx = 0;
+        int qsize = 0;
+
+        /* Reset device */
+        // XXX That will clear the virtq base. We need to move
+        //     initializing it to here anyway
+        //
+        //     virtio_reset_device(dev);
+
+        /* Acknowledge device. */
+        virtio_set_status(dev, VIRTIO_STAT_ACKNOWLEDGE);
+
+        /* Tell HV that we know how to drive the device. */
+        virtio_set_status(dev, VIRTIO_STAT_ACKNOWLEDGE|VIRTIO_STAT_DRIVER);
+
+        /* Device specific setup - we do not support special features right now */
+        virtio_set_guest_features(dev,  0);
+
+        while(1) {
+                qsize = virtio_get_qsize(dev, idx);
+                if (!qsize)
+                        break;
+                virtio_vring_size(qsize);
+
+                vq_avail = virtio_get_vring_avail(dev, 0);
+                vq_avail->flags = VRING_AVAIL_F_NO_INTERRUPT;
+                vq_avail->idx = 0;
+                idx++;
+        }
+
+	/* Tell HV that setup succeeded */
+ 	virtio_set_status(dev, VIRTIO_STAT_ACKNOWLEDGE|VIRTIO_STAT_DRIVER
+                          |VIRTIO_STAT_DRIVER_OK);
+
+	return 0;
+}
+
+/**
+ * Shutdown the virtio-block device.
+ * @param  dev  pointer to virtio device information
+ */
+void virtioscsi_shutdown(struct virtio_device *dev)
+{
+	/* Quiesce device */
+	virtio_set_status(dev, VIRTIO_STAT_FAILED);
+
+	/* Reset device */
+	virtio_reset_device(dev);
+}
diff --git a/lib/libvirtio/virtio-scsi.h b/lib/libvirtio/virtio-scsi.h
new file mode 100644
index 0000000..451ba4d
--- /dev/null
+++ b/lib/libvirtio/virtio-scsi.h
@@ -0,0 +1,69 @@
+/******************************************************************************
+ * Copyright (c) 2012 IBM Corporation
+ * All rights reserved.
+ * This program and the accompanying materials
+ * are made available under the terms of the BSD License
+ * which accompanies this distribution, and is available at
+ * http://www.opensource.org/licenses/bsd-license.php
+ *
+ * Contributors:
+ *     IBM Corporation - initial implementation
+ *****************************************************************************/
+
+/*
+ * Virtio SCSI Host device definitions.
+ * See Virtio Spec, Appendix I, for details
+ */
+
+#ifndef _VIRTIO_SCSI_H
+#define _VIRTIO_SCSI_H
+
+#define VIRTIO_SCSI_CDB_SIZE      32
+#define VIRTIO_SCSI_SENSE_SIZE    96
+
+#define VIRTIO_SCSI_CONTROL_VQ     0
+#define VIRTIO_SCSI_EVENT_VQ       1
+#define VIRTIO_SCSI_REQUEST_VQ     2
+
+struct virtio_scsi_config
+{
+    uint32_t num_queues;
+    uint32_t seg_max;
+    uint32_t max_sectors;
+    uint32_t cmd_per_lun;
+    uint32_t event_info_size;
+    uint32_t sense_size;
+    uint32_t cdb_size;
+    uint16_t max_channel;
+    uint16_t max_target;
+    uint32_t max_lun;
+} __attribute__((packed));
+
+/* This is the first element of the "out" scatter-gather list. */
+struct virtio_scsi_req_cmd {
+    uint8_t lun[8];
+    uint64_t tag;
+    uint8_t task_attr;
+    uint8_t prio;
+    uint8_t crn;
+    char cdb[VIRTIO_SCSI_CDB_SIZE];
+};
+
+/* This is the first element of the "in" scatter-gather list. */
+struct virtio_scsi_resp_cmd {
+    uint32_t sense_len;
+    uint32_t residual;
+    uint16_t status_qualifier;
+    uint8_t status;
+    uint8_t response;
+    uint8_t sense[VIRTIO_SCSI_SENSE_SIZE];
+};
+
+extern int virtioscsi_init(struct virtio_device *dev);
+extern void virtioscsi_shutdown(struct virtio_device *dev);
+extern int virtioscsi_send(struct virtio_device *dev,
+			   struct virtio_scsi_req_cmd *req,
+			   struct virtio_scsi_resp_cmd *resp,
+			   int is_read, void *buf, uint64_t buf_len);
+
+#endif /*  _VIRTIO_SCSI_H */
diff --git a/lib/libvirtio/virtio.code b/lib/libvirtio/virtio.code
index 100cc96..9c50c92 100644
--- a/lib/libvirtio/virtio.code
+++ b/lib/libvirtio/virtio.code
@@ -13,6 +13,7 @@
 #include <virtio.h>
 #include <virtio-blk.h>
 #include <virtio-9p.h>
+#include <virtio-scsi.h>
 
 /******** core virtio ********/
 
@@ -92,3 +93,29 @@ PRIM(virtio_X2d_fs_X2d_load)
 
 	TOS.n = virtio_9p_load(dev, str, buf);
 MIRP
+
+/******** virtio-scsi ********/
+
+// : virtio-scsi-init ( dev -- success )
+PRIM(virtio_X2d_scsi_X2d_init)
+	void *dev = TOS.a;
+	TOS.u = virtioscsi_init(dev);
+MIRP
+
+// : virtio-scsi-shutdown ( dev -- )
+PRIM(virtio_X2d_scsi_X2d_shutdown)
+	void *dev = TOS.a; POP;
+	virtioscsi_shutdown(dev);
+MIRP
+
+// : virtio-scsi-send ( buf_addr buf_len is_read req_ptr rsp_ptr dev -- success)
+PRIM(virtio_X2d_scsi_X2d_send)
+	void *dev	= TOS.a; POP;
+	void *resp	= TOS.a; POP;
+	void *req	= TOS.a; POP;
+	int is_read	= !!TOS.n; POP;
+	uint64_t blen	= TOS.n; POP;
+	void *buf	= TOS.a;
+	TOS.n = virtioscsi_send(dev, req, resp, is_read, buf, blen);
+MIRP
+
diff --git a/lib/libvirtio/virtio.in b/lib/libvirtio/virtio.in
index a702779..e62341d 100644
--- a/lib/libvirtio/virtio.in
+++ b/lib/libvirtio/virtio.in
@@ -19,6 +19,10 @@ cod(virtio-blk-init)
 cod(virtio-blk-shutdown)
 cod(virtio-blk-read)
 
+cod(virtio-scsi-init)
+cod(virtio-scsi-shutdown)
+cod(virtio-scsi-send)
+
 cod(virtio-fs-init)
 cod(virtio-fs-shutdown)
 cod(virtio-fs-load)