virsh: Allow attach-disk to specify disk target bus

By default, the bus type is inferred from the style of the device
name('target' in this command), e.g. a device named 'sda' will
typically be exported using a SCSI bus. Actually, not only SCSI bus,
but USB/SATA bus also use this kind of device name. So add '--bus'
option for attach-disk command to allow user specify the target bus.
Signed-off-by: NYanbing Du <ydu@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

tools/virsh-domain.c

@@ -277,6 +277,10 @@ static const vshCmdOptDef opts_attach_disk[] = {
      .flags = VSH_OFLAG_REQ,
      .help = N_("target of disk device")
     },
+    {.name = "targetbus",
+     .type = VSH_OT_STRING,
+     .help = N_("target bus of disk device")
+    },
     {.name = "driver",
      .type = VSH_OT_STRING,
      .help = N_("driver of disk device")
@@ -502,7 +506,7 @@ cmdAttachDisk(vshControl *ctl, const vshCmd *cmd)
     const char *source = NULL, *target = NULL, *driver = NULL,
                 *subdriver = NULL, *type = NULL, *mode = NULL,
                 *cache = NULL, *serial = NULL, *straddr = NULL,
-                *wwn = NULL;
+                *wwn = NULL, *targetbus = NULL;
     struct DiskAddress diskAddr;
     bool isFile = false, functionReturn = false;
     int ret;
@@ -536,6 +540,7 @@ cmdAttachDisk(vshControl *ctl, const vshCmd *cmd)
         vshCommandOptStringReq(ctl, cmd, "serial", &serial) < 0 ||
         vshCommandOptStringReq(ctl, cmd, "wwn", &wwn) < 0 ||
         vshCommandOptStringReq(ctl, cmd, "address", &straddr) < 0 ||
+        vshCommandOptStringReq(ctl, cmd, "targetbus", &targetbus) < 0 ||
         vshCommandOptStringReq(ctl, cmd, "sourcetype", &stype) < 0)
         goto cleanup;
 
@@ -590,7 +595,11 @@ cmdAttachDisk(vshControl *ctl, const vshCmd *cmd)
     if (source)
         virBufferAsprintf(&buf, "<source %s='%s'/>\n",
                           isFile ? "file" : "dev", source);
-    virBufferAsprintf(&buf, "<target dev='%s'/>\n", target);
+    virBufferAsprintf(&buf, "<target dev='%s'", target);
+    if (targetbus)
+        virBufferAsprintf(&buf, " bus='%s'", targetbus);
+    virBufferAddLit(&buf, "/>\n");
+
     if (mode)
         virBufferAsprintf(&buf, "<%s/>\n", mode);
 

tools/virsh.pod

@@ -2089,17 +2089,21 @@ B<Note>: using of partial device definition XML files may lead to unexpected
 results as some fields may be autogenerated and thus match devices other than
 expected.
 
-=item B<attach-disk> I<domain> I<source> I<target>
-[[[I<--live>] [I<--config>] | [I<--current>]] | [I<--persistent>]]
-[I<--driver driver>] [I<--subdriver subdriver>] [I<--cache cache>]
-[I<--type type>] [I<--mode mode>] [I<--sourcetype sourcetype>]
-[I<--serial serial>] [I<--wwn wwn>] [I<--rawio>]
-[I<--address address>] [I<--multifunction>] [I<--print-xml>]
+=item B<attach-disk> I<domain> I<source> I<target> [[[I<--live>] [I<--config>]
+| [I<--current>]] | [I<--persistent>]] [I<--targetbus bus>] [I<--driver
+driver>] [I<--subdriver subdriver>] [I<--cache cache>] [I<--type type>]
+[I<--mode mode>] [I<--sourcetype sourcetype>] [I<--serial serial>] [I<--wwn
+wwn>] [I<--rawio>] [I<--address address>] [I<--multifunction>] [I<--print-xml>]
 
 Attach a new disk device to the domain.
 I<source> is path for the files and devices. I<target> controls the bus or
 device under which the disk is exposed to the guest OS. It indicates the
-"logical" device name.  I<driver> can be I<file>, I<tap> or I<phy> for the Xen
+"logical" device name; the optional I<targetbus> attribute specifies the type
+of disk device to emulate; possible values are driver specific, with typical
+values being I<ide>, I<scsi>, I<virtio>, I<xen>, I<usb>, I<sata>, or I<sd>, if
+omitted, the bus type is inferred from the style of the device name (e.g.  a
+device named 'sda' will typically be exported using a SCSI bus).  I<driver> can
+be I<file>, I<tap> or I<phy> for the Xen
 hypervisor depending on the kind of access; or I<qemu> for the QEMU emulator.
 Further details to the driver can be passed using I<subdriver>. For Xen
 I<subdriver> can be I<aio>, while for QEMU subdriver should match the format