vhost-user-scsi: Introduce vhost-user-scsi host device

This commit introduces a vhost-user device for SCSI. This is based
on the existing vhost-scsi implementation, but done over vhost-user
instead. It also uses a chardev to connect to the backend. Unlike
vhost-scsi (today), VMs using vhost-user-scsi can be live migrated.

To use it, start Qemu with a command line equivalent to:

qemu-system-x86_64 \
       -chardev socket,id=vus0,path=/tmp/vus.sock \
       -device vhost-user-scsi-pci,chardev=vus0,bus=pci.0,addr=...

A separate commit presents a sample application linked with libiscsi to
provide a backend for vhost-user-scsi.

Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Message-Id: <1488479153-21203-4-git-send-email-felipe@nutanix.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 37 insertions, 0 deletions

diff --git a/include/hw/virtio/vhost-user-scsi.h b/include/hw/virtio/vhost-user-scsi.h
new file mode 100644
index 0000000000..01861f78d0
--- /dev/null
+++ b/include/hw/virtio/vhost-user-scsi.h
@@ -0,0 +1,35 @@
+/*
+ * vhost-user-scsi host device
+ *
+ * Copyright (c) 2016 Nutanix Inc. All rights reserved.
+ *
+ * Author:
+ *  Felipe Franciosi <felipe@nutanix.com>
+ *
+ * This file is largely based on "vhost-scsi.h" by:
+ *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#ifndef VHOST_USER_SCSI_H
+#define VHOST_USER_SCSI_H
+
+#include "qemu-common.h"
+#include "hw/qdev.h"
+#include "hw/virtio/virtio-scsi.h"
+#include "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-scsi-common.h"
+
+#define TYPE_VHOST_USER_SCSI "vhost-user-scsi"
+#define VHOST_USER_SCSI(obj) \
+        OBJECT_CHECK(VHostUserSCSI, (obj), TYPE_VHOST_USER_SCSI)
+
+typedef struct VHostUserSCSI {
+    VHostSCSICommon parent_obj;
+    uint64_t host_features;
+} VHostUserSCSI;
+
+#endif /* VHOST_USER_SCSI_H */
diff --git a/include/hw/virtio/virtio-scsi.h b/include/hw/virtio/virtio-scsi.h
index eac2013ddd..de6ae5a9f6 100644
--- a/include/hw/virtio/virtio-scsi.h
+++ b/include/hw/virtio/virtio-scsi.h
@@ -21,6 +21,7 @@
 #include "hw/virtio/virtio.h"
 #include "hw/pci/pci.h"
 #include "hw/scsi/scsi.h"
+#include "chardev/char-fe.h"
 #include "sysemu/iothread.h"
 
 #define TYPE_VIRTIO_SCSI_COMMON "virtio-scsi-common"
@@ -53,6 +54,7 @@ struct VirtIOSCSIConf {
     char *vhostfd;
     char *wwpn;
 #endif
+    CharBackend chardev;
     uint32_t boot_tpgt;
     IOThread *iothread;
 };