[PATCH v5 04/21] libxl: Allow running qemu-xen in stubdomain

[Jason Andryuk <jandryuk@gmail.com>]

From: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>

Do not prohibit anymore using stubdomain with qemu-xen.
To help distingushing MiniOS and Linux stubdomain, add helper inline
functions libxl__stubdomain_is_linux() and
libxl__stubdomain_is_linux_running(). Those should be used where really
the difference is about MiniOS/Linux, not qemu-xen/qemu-xen-traditional.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>

---
Changes in v3:
 - new patch, instead of "libxl: Add "stubdomain_version" to
 domain_build_info"
 - helper functions as suggested by Ian Jackson
---
 tools/libxl/libxl_create.c   |  9 ---------
 tools/libxl/libxl_internal.h | 17 +++++++++++++++++
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index e7cb2dbc2b..7423ee8e57 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -171,15 +171,6 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
         }
     }
 
-    if (b_info->type == LIBXL_DOMAIN_TYPE_HVM &&
-        b_info->device_model_version !=
-            LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL &&
-        libxl_defbool_val(b_info->device_model_stubdomain)) {
-        LOG(ERROR,
-            "device model stubdomains require \"qemu-xen-traditional\"");
-        return ERROR_INVAL;
-    }
-
     if (!b_info->max_vcpus)
         b_info->max_vcpus = 1;
     if (!b_info->avail_vcpus.size) {
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 5f39e44cb9..ebbf926897 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -2320,6 +2320,23 @@ _hidden int libxl__device_model_version_running(libxl__gc *gc, uint32_t domid);
   /* Return the system-wide default device model */
 _hidden libxl_device_model_version libxl__default_device_model(libxl__gc *gc);
 
+static inline
+bool libxl__stubdomain_is_linux_running(libxl__gc *gc, uint32_t domid)
+{
+    /* same logic as in libxl__stubdomain_is_linux */
+    return libxl__device_model_version_running(gc, domid)
+        == LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN;
+}
+
+static inline
+bool libxl__stubdomain_is_linux(libxl_domain_build_info *b_info)
+{
+    /* right now qemu-tranditional implies MiniOS stubdomain and qemu-xen
+     * implies Linux stubdomain */
+    return libxl_defbool_val(b_info->device_model_stubdomain) &&
+        b_info->device_model_version == LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN;
+}
+
 #define DEVICE_MODEL_XS_PATH(gc, dm_domid, domid, fmt, _a...)              \
     libxl__sprintf(gc, "/local/domain/%u/device-model/%u" fmt, dm_domid,   \
                    domid, ##_a)
-- 
2.20.1