Re: [Xen-devel] [PATCH v2] libxl: make vkbd tunable for HVM guests

["Elnikety, Eslam" <elnikety@xxxxxxxxxx>]

> On 7. May 2019, at 15:53, Eslam Elnikety <elnikety@xxxxxxxxxx> wrote:
> 
> 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>
> 
> ---
>    Changes in v2:
>        - Added a missing hunk / setting vkb_device per config
> ---
> tools/libxl/libxl_create.c  | 9 ++++++---
> tools/libxl/libxl_types.idl | 1 +
> tools/xl/xl_parse.c         | 1 +
> tools/xl/xl_sxp.c           | 2 ++
> 4 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
> index 89fe80fc9c..03ce166f4f 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_parse.c b/tools/xl/xl_parse.c
> index 352cd214dd..e105bda2bb 100644
> --- a/tools/xl/xl_parse.c
> +++ b/tools/xl/xl_parse.c
> @@ -2652,6 +2652,7 @@ skip_usbdev:
>             fprintf(stderr,"xl: Unable to parse usbdevice.\n");
>             exit(-ERROR_FAIL);
>         }
> +        xlu_cfg_get_defbool(config, "vkb_device", &b_info->u.hvm.vkb_device, 
> 0);
>         xlu_cfg_replace_string (config, "soundhw", &b_info->u.hvm.soundhw, 0);
>         xlu_cfg_get_defbool(config, "xen_platform_pci",
>                             &b_info->u.hvm.xen_platform_pci, 0);
> 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
> 


Wei, any particular thoughts on v2?

Cheers,
Eslam


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