Add virtio-blk support

Virtio-blk is a paravirtual block device based on VirtIO.  It can be used by
specifying the if=virtio parameter to the -drive parameter.

When using -enable-kvm, it can achieve very good performance compared to IDE or
SCSI.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5870 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 76 insertions, 0 deletions

diff --git a/hw/virtio-blk.h b/hw/virtio-blk.h
new file mode 100644
index 000000000..c6661c0ad
--- /dev/null
+++ b/hw/virtio-blk.h
@@ -0,0 +1,76 @@
+/*
+ * Virtio Block Device
+ *
+ * Copyright IBM, Corp. 2007
+ *
+ * Authors:
+ *  Anthony Liguori   <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef _QEMU_VIRTIO_BLK_H
+#define _QEMU_VIRTIO_BLK_H
+
+#include "virtio.h"
+#include "block.h"
+#include "pci.h"
+
+/* from Linux's linux/virtio_blk.h */
+
+/* The ID for virtio_block */
+#define VIRTIO_ID_BLOCK 2
+
+/* Feature bits */
+#define VIRTIO_BLK_F_BARRIER    0       /* Does host support barriers? */
+#define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */
+#define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */
+#define VIRTIO_BLK_F_GEOMETRY   4       /* Indicates support of legacy geometry */
+
+struct virtio_blk_config
+{
+    uint64_t capacity;
+    uint32_t size_max;
+    uint32_t seg_max;
+    uint16_t cylinders;
+    uint8_t heads;
+    uint8_t sectors;
+} __attribute__((packed));
+
+/* These two define direction. */
+#define VIRTIO_BLK_T_IN         0
+#define VIRTIO_BLK_T_OUT        1
+
+/* This bit says it's a scsi command, not an actual read or write. */
+#define VIRTIO_BLK_T_SCSI_CMD   2
+
+/* Barrier before this op. */
+#define VIRTIO_BLK_T_BARRIER    0x80000000
+
+/* This is the first element of the read scatter-gather list. */
+struct virtio_blk_outhdr
+{
+    /* VIRTIO_BLK_T* */
+    uint32_t type;
+    /* io priority. */
+    uint32_t ioprio;
+    /* Sector (ie. 512 byte offset) */
+    uint64_t sector;
+};
+
+#define VIRTIO_BLK_S_OK         0
+#define VIRTIO_BLK_S_IOERR      1
+#define VIRTIO_BLK_S_UNSUPP     2
+
+/* This is the first element of the write scatter-gather list */
+struct virtio_blk_inhdr
+{
+    unsigned char status;
+};
+
+void *virtio_blk_init(PCIBus *bus, uint16_t vendor, uint16_t device,
+                      BlockDriverState *bs);
+
+#endif