virtio-blk: add helpers for filling descriptors

Enable virtio_fill_desc/fill_blk_hdr with legacy and modern mode for
further use

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

3 files changed, 44 insertions, 15 deletions

diff --git a/lib/libvirtio/virtio-blk.c b/lib/libvirtio/virtio-blk.c
index 1a8ee1b..d7a3039 100644
--- a/lib/libvirtio/virtio-blk.c
+++ b/lib/libvirtio/virtio-blk.c
@@ -13,6 +13,7 @@
 #include <stdio.h>
 #include <cpu.h>
 #include <helpers.h>
+#include <byteorder.h>
 #include "virtio.h"
 #include "virtio-blk.h"
 
@@ -82,6 +83,19 @@ virtioblk_shutdown(struct virtio_device *dev)
 	virtio_reset_device(dev);
 }
 
+static void fill_blk_hdr(struct virtio_blk_req *blkhdr, bool is_modern,
+                         uint32_t type, uint32_t ioprio, uint32_t sector)
+{
+	if (is_modern) {
+		blkhdr->type = cpu_to_le32(type);
+		blkhdr->ioprio = cpu_to_le32(ioprio);
+		blkhdr->sector = cpu_to_le64(sector);
+	} else {
+		blkhdr->type = type;
+		blkhdr->ioprio = ioprio;
+		blkhdr->sector = sector;
+	}
+}
 
 /**
  * Read blocks
@@ -137,33 +151,25 @@ virtioblk_read(struct virtio_device *dev, char *buf, uint64_t blocknum, long cnt
 	current_used_idx = &vq_used->idx;
 
 	/* Set up header */
-	blkhdr.type = VIRTIO_BLK_T_IN | VIRTIO_BLK_T_BARRIER;
-	blkhdr.ioprio = 1;
-	blkhdr.sector = blocknum * blk_size / DEFAULT_SECTOR_SIZE;
+	fill_blk_hdr(&blkhdr, false, VIRTIO_BLK_T_IN | VIRTIO_BLK_T_BARRIER,
+		     1, blocknum * blk_size / DEFAULT_SECTOR_SIZE);
 
 	/* Determine descriptor index */
 	id = (vq_avail->idx * 3) % vq_size;
 
 	/* Set up virtqueue descriptor for header */
 	desc = &vq_desc[id];
-	desc->addr = (uint64_t)&blkhdr;
-	desc->len = sizeof(struct virtio_blk_req);
-	desc->flags = VRING_DESC_F_NEXT;
-	desc->next = (id + 1) % vq_size;
+	virtio_fill_desc(desc, false, (uint64_t)&blkhdr, sizeof(struct virtio_blk_req),
+		  VRING_DESC_F_NEXT, (id + 1) % vq_size);
 
 	/* Set up virtqueue descriptor for data */
 	desc = &vq_desc[(id + 1) % vq_size];
-	desc->addr = (uint64_t)buf;
-	desc->len = cnt * blk_size;
-	desc->flags = VRING_DESC_F_NEXT | VRING_DESC_F_WRITE;
-	desc->next = (id + 2) % vq_size;
+	virtio_fill_desc(desc, false, (uint64_t)buf, cnt * blk_size,
+		  VRING_DESC_F_NEXT | VRING_DESC_F_WRITE, (id + 2) % vq_size);
 
 	/* Set up virtqueue descriptor for status */
 	desc = &vq_desc[(id + 2) % vq_size];
-	desc->addr = (uint64_t)&status;
-	desc->len = 1;
-	desc->flags = VRING_DESC_F_WRITE;
-	desc->next = 0;
+	virtio_fill_desc(desc, false, (uint64_t)&status, 1, VRING_DESC_F_WRITE, 0);
 
 	vq_avail->ring[vq_avail->idx % vq_size] = id;
 	mb();
diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c
index 063a621..4ea8278 100644
--- a/lib/libvirtio/virtio.c
+++ b/lib/libvirtio/virtio.c
@@ -113,6 +113,25 @@ struct vring_used *virtio_get_vring_used(struct virtio_device *dev, int queue)
 			       * sizeof(struct vring_avail));
 }
 
+/**
+ * Fill the virtio ring descriptor depending on the legacy mode or virtio 1.0
+ */
+void virtio_fill_desc(struct vring_desc *desc, bool is_modern,
+                      uint64_t addr, uint32_t len,
+                      uint16_t flags, uint16_t next)
+{
+	if (is_modern) {
+		desc->addr = cpu_to_le64(addr);
+		desc->len = cpu_to_le32(len);
+		desc->flags = cpu_to_le16(flags);
+		desc->next = cpu_to_le16(next);
+	} else {
+		desc->addr = addr;
+		desc->len = len;
+		desc->flags = flags;
+		desc->next = next;
+	}
+}
 
 /**
  * Reset virtio device
diff --git a/lib/libvirtio/virtio.h b/lib/libvirtio/virtio.h
index e41f47d..c26282f 100644
--- a/lib/libvirtio/virtio.h
+++ b/lib/libvirtio/virtio.h
@@ -14,6 +14,7 @@
 #define _LIBVIRTIO_H
 
 #include <stdint.h>
+#include <stdbool.h>
 
 /* Device status bits */
 #define VIRTIO_STAT_ACKNOWLEDGE		1
@@ -83,6 +84,9 @@ extern int virtio_get_qsize(struct virtio_device *dev, int queue);
 extern struct vring_desc *virtio_get_vring_desc(struct virtio_device *dev, int queue);
 extern struct vring_avail *virtio_get_vring_avail(struct virtio_device *dev, int queue);
 extern struct vring_used *virtio_get_vring_used(struct virtio_device *dev, int queue);
+extern void virtio_fill_desc(struct vring_desc *desc, bool is_modern,
+                             uint64_t addr, uint32_t len,
+                             uint16_t flags, uint16_t next);
 extern int virtio_queue_init_vq(struct virtio_device *dev, struct vqs *vq, unsigned int id);
 
 extern void virtio_reset_device(struct virtio_device *dev);