[Xen-devel] [PATCH] libxl: make vkbd tunable for HVM guests

[Eslam Elnikety <elnikety@xxxxxxxxxx>]

Each HVM guest currently gets a vkbd frontend/backend pair (c/s ebbd2561b4c).
This consumes host resources unnecessarily for guests that have no use for
vkbd. Make this behaviour tunable to allow an administrator to choose. The
commit retains the current behaviour -- HVM guests still get vkdb unless
specified otherwise.

Signed-off-by: Eslam Elnikety <elnikety@xxxxxxxxxx>
---
 tools/libxl/libxl_create.c  | 9 ++++++---
 tools/libxl/libxl_types.idl | 1 +
 tools/xl/xl_sxp.c           | 2 ++
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
index 89fe80fc9c..b09244058f 100644
--- a/tools/libxl/libxl_create.c
+++ b/tools/libxl/libxl_create.c
@@ -310,6 +310,7 @@ int libxl__domain_build_info_setdefault(libxl__gc *gc,
         libxl_defbool_setdefault(&b_info->u.hvm.vpt_align,          true);
         libxl_defbool_setdefault(&b_info->u.hvm.altp2m,             false);
         libxl_defbool_setdefault(&b_info->u.hvm.usb,                false);
+        libxl_defbool_setdefault(&b_info->u.hvm.vkb_device,         true);
         libxl_defbool_setdefault(&b_info->u.hvm.xen_platform_pci,   true);
 
         libxl_defbool_setdefault(&b_info->u.hvm.spice.enable, false);
@@ -1416,9 +1417,11 @@ static void domcreate_launch_dm(libxl__egc *egc, 
libxl__multidev *multidev,
         libxl__device_console_add(gc, domid, &console, state, &device);
         libxl__device_console_dispose(&console);
 
-        libxl_device_vkb_init(&vkb);
-        libxl__device_add(gc, domid, &libxl__vkb_devtype, &vkb);
-        libxl_device_vkb_dispose(&vkb);
+        if ( libxl_defbool_val(d_config->b_info.u.hvm.vkb_device) ) {
+            libxl_device_vkb_init(&vkb);
+            libxl__device_add(gc, domid, &libxl__vkb_devtype, &vkb);
+            libxl_device_vkb_dispose(&vkb);
+        }
 
         dcs->sdss.dm.guest_domid = domid;
         if (libxl_defbool_val(d_config->b_info.device_model_stubdomain))
diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index b685ac47ac..9a0b92f1d4 100644
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -583,6 +583,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
                                        # - "tablet" for absolute mouse,
                                        # - "mouse" for PS/2 protocol relative 
mouse
                                        ("usbdevice",        string),
+                                       ("vkb_device",       libxl_defbool),
                                        ("soundhw",          string),
                                        ("xen_platform_pci", libxl_defbool),
                                        ("usbdevice_list",   libxl_string_list),
diff --git a/tools/xl/xl_sxp.c b/tools/xl/xl_sxp.c
index 3e6117d0cd..359a001570 100644
--- a/tools/xl/xl_sxp.c
+++ b/tools/xl/xl_sxp.c
@@ -138,6 +138,8 @@ void printf_info_sexp(int domid, libxl_domain_config 
*d_config, FILE *fh)
         fprintf(fh, "\t\t\t(boot %s)\n", b_info->u.hvm.boot);
         fprintf(fh, "\t\t\t(usb %s)\n", 
libxl_defbool_to_string(b_info->u.hvm.usb));
         fprintf(fh, "\t\t\t(usbdevice %s)\n", b_info->u.hvm.usbdevice);
+        fprintf(fh, "\t\t\t(vkb_device %s)\n",
+               libxl_defbool_to_string(b_info->u.hvm.vkb_device));
         fprintf(fh, "\t\t)\n");
         break;
     case LIBXL_DOMAIN_TYPE_PV:
-- 
2.15.3.AMZN


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