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
diff --git a/vl.c b/vl.c
index e4edf20..2b5366e 100644
--- a/vl.c
+++ b/vl.c
@@ -2267,7 +2267,10 @@
 	} else if (!strcmp(buf, "sd")) {
 	    type = IF_SD;
             max_devs = 0;
-	} else {
+        } else if (!strcmp(buf, "virtio")) {
+            type = IF_VIRTIO;
+            max_devs = 0;
+        } else {
             fprintf(stderr, "qemu: '%s' unsupported bus type '%s'\n", str, buf);
             return -1;
 	}
@@ -2474,6 +2477,7 @@
         break;
     case IF_PFLASH:
     case IF_MTD:
+    case IF_VIRTIO:
         break;
     }
     if (!file[0])