libxl: Support PV consoles

Currently the driver only exposes the ability to connect to the serial console
of a Xen guest, which doesn't work for a PV guest. Since for an HVM guest the
serial devices are duplicated as consoles it is sufficient to just use the
console devices unconditionally.

Tested with the following bit of config XML:

<domain type='xen'>
  ...
  <devices>
    <console type='pty'>
      <target type='xen'/>
    </console>
  </devices>
</domain>

I have observed and tested this on ARM but I believe it also applies to x86 PV
guests.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Jim Fehlig <jfehlig@suse.com>
Cc: Dario Faggioli <dario.faggioli@citrix.com>
Cc: Clark Laughlin <clark.laughlin@linaro.org>

src/libxl/libxl_driver.c

@@ -3780,6 +3780,7 @@ libxlDomainOpenConsole(virDomainPtr dom,
 {
     virDomainObjPtr vm = NULL;
     int ret = -1;
+    libxl_console_type console_type;
     virDomainChrDefPtr chr = NULL;
     libxlDomainObjPrivatePtr priv;
     char *console = NULL;
@@ -3807,8 +3808,8 @@ libxlDomainOpenConsole(virDomainPtr dom,
 
     priv = vm->privateData;
 
-    if (vm->def->nserials)
-        chr = vm->def->serials[0];
+    if (vm->def->nconsoles)
+        chr = vm->def->consoles[0];
 
     if (!chr) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -3824,7 +3825,12 @@ libxlDomainOpenConsole(virDomainPtr dom,
         goto cleanup;
     }
 
-    ret = libxl_primary_console_get_tty(priv->ctx, vm->def->id, &console);
+    console_type =
+        (chr->targetType == VIR_DOMAIN_CHR_CONSOLE_TARGET_TYPE_SERIAL ?
+                            LIBXL_CONSOLE_TYPE_SERIAL : LIBXL_CONSOLE_TYPE_PV);
+
+    ret = libxl_console_get_tty(priv->ctx, vm->def->id, chr->target.port,
+                                console_type, &console);
     if (ret)
         goto cleanup;