blktap3/libxl: add support for blktap3 in libxl

@@ -859,6 +859,7 @@ static void setformat(DiskParseContext *
 static void setbackendtype(DiskParseContext *dpc, const char *str) {
     if (     !strcmp(str,"phy"))   DSET(dpc,backend,BACKEND,str,PHY);
     else if (!strcmp(str,"tap"))   DSET(dpc,backend,BACKEND,str,TAP);
+    else if (!strcmp(str,"tap3"))   DSET(dpc,backend,BACKEND,str,TAP3);
     else if (!strcmp(str,"qdisk")) DSET(dpc,backend,BACKEND,str,QDISK);
     else xlu__disk_err(dpc,str,"unknown value for backendtype");
 }

54 lines not on this page · raw message

@@ -1338,6 +1338,14 @@ struct libxl__cpuid_policy {
 };
 
 /*
+ * blktap3 support
+ */
+/* libxl__blktap_enabled:
+ *    return true if blktap3 support is available.
+ */
+_hidden int libxl__blktap3_enabled(libxl__gc *gc);
+
+/*
  * blktap2 support
  */
 

new file mode 100644
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2012      Citrix Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
+ * USA.
+ */
+
+#include "libxl_osdeps.h" /* must come before any other headers */
+#include "libxl_internal.h"
+
+int libxl__blktap3_enabled(libxl__gc *gc)
+{
+    return 0;
+}

@@ -1159,6 +1159,8 @@ static void disk_eject_xswatch_callback(
         disk->backend = LIBXL_DISK_BACKEND_TAP;
     } else if (!strcmp(backend_type, "qdisk")) {
         disk->backend = LIBXL_DISK_BACKEND_QDISK;
+    } else if (!strcmp(backend_type, "tap3")) {
+        disk->backend = LIBXL_DISK_BACKEND_TAP3;
     } else {
         disk->backend = LIBXL_DISK_BACKEND_UNKNOWN;
     }

@@ -2012,6 +2014,9 @@ int libxl__device_from_disk(libxl__gc *g
         case LIBXL_DISK_BACKEND_QDISK:
             device->backend_kind = LIBXL__DEVICE_KIND_QDISK;
             break;
+        case LIBXL_DISK_BACKEND_TAP3:
+            device->backend_kind = LIBXL__DEVICE_KIND_VBD3;
+            break;
         default:
             LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk backend type: %d\n",
                        disk->backend);

@@ -2130,11 +2135,15 @@ static void device_disk_add(libxl__egc *
 
                 /* now create a phy device to export the device to the guest */
                 goto do_backend_phy;
+            case LIBXL_DISK_BACKEND_TAP3:
             case LIBXL_DISK_BACKEND_QDISK:
                 flexarray_append(back, "params");
                 flexarray_append(back, libxl__sprintf(gc, "%s:%s",
                               libxl__device_disk_string_of_format(disk->format), disk->pdev_path));
-                assert(device->backend_kind == LIBXL__DEVICE_KIND_QDISK);
+                assert(
+                        (disk->backend == LIBXL_DISK_BACKEND_QDISK
+                         && device->backend_kind == LIBXL__DEVICE_KIND_QDISK)
+                        || (disk->backend == LIBXL_DISK_BACKEND_TAP3));
                 break;
             default:
                 LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk backend type: %d\n", disk->backend);

@@ -190,6 +190,23 @@ static int disk_try_backend(disk_try_bac
         }
         return backend;
 
+    case LIBXL_DISK_BACKEND_TAP3:
+        /* TODO What's that script thing? */
+        if (a->disk->script) goto bad_script;
+
+        if (!libxl__blktap3_enabled(a->gc)) {
+            LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Disk vdev=%s, backend tap"
+                       " unsuitable because blktap3 not available",
+                       a->disk->vdev);
+            return 0;
+        }
+        /* TODO other formats supported by blktap3? */
+        if (!(a->disk->format == LIBXL_DISK_FORMAT_RAW ||
+              a->disk->format == LIBXL_DISK_FORMAT_VHD)) {
+            goto bad_format;
+        }
+        return backend;
+
     case LIBXL_DISK_BACKEND_QDISK:
         if (a->disk->script) goto bad_script;
         return backend;

@@ -258,6 +275,7 @@ int libxl__device_disk_set_backend(libxl
         ok=
             disk_try_backend(&a, LIBXL_DISK_BACKEND_PHY) ?:
             disk_try_backend(&a, LIBXL_DISK_BACKEND_TAP) ?:
+            disk_try_backend(&a, LIBXL_DISK_BACKEND_TAP3) ?:
             disk_try_backend(&a, LIBXL_DISK_BACKEND_QDISK);
         if (ok)
             LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "Disk vdev=%s, using backend %s",

@@ -290,6 +308,7 @@ char *libxl__device_disk_string_of_backe
     switch (backend) {
         case LIBXL_DISK_BACKEND_QDISK: return "qdisk";
         case LIBXL_DISK_BACKEND_TAP: return "phy";
+        case LIBXL_DISK_BACKEND_TAP3: return "phy";
         case LIBXL_DISK_BACKEND_PHY: return "phy";
         default: return NULL;
     }