Re: [libvirt] [PATCH 8/9] libxl: pass cmdline to HVM guests
On Fri, Mar 20, 2015 at 11:18:36AM -0600, Jim Fehlig wrote:
Marek Marczykowski-Górecki wrote:
> Signed-off-by: Marek Marczykowski-Górecki <marmarek(a)invisiblethingslab.com>
> ---
> src/libxl/libxl_conf.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
> index 8ec3c75..d78d2b2 100644
> --- a/src/libxl/libxl_conf.c
> +++ b/src/libxl/libxl_conf.c
> @@ -735,6 +735,14 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
> libxl_defbool_set(&b_info->device_model_stubdomain,
> def->stubdomain == VIR_TRISTATE_BOOL_YES);
>
> + if (def->os.cmdline && def->os.cmdline[0]) {
> + b_info->extra_hvm = virStringSplit(def->os.cmdline, "
", 0);
>
What is the difference between b_info->extra_hvm and b_info->cmdline?
How are these two reconciled in libxl? I.e., what if they contained
In short, I don't think you should use that field at all.
b_info->extra_hvm contains the parameters passed to QEMU specifically
for HVM guest. Those parameters are not meant to be kernel command line.
That field is introduced so that user can append arbitrary parameters to
QEMU. I think it's only a stopgap for things we have not implemented in
libxl or things we don't want to put into libxl. In reality I think it
is rarely used.
different values? Chunyan added the latter with xen commit
11dffa235
when implementing hvm direct kernel boot. She also submitted a patch
for libvirt
https://www.redhat.com/archives/libvir-list/2014-September/msg01006.html
I reworked that patch to support the recent breakout of xl and xm config
in src/xenconfig. While doing so, I fixed other <os> related issues and
posted this series
https://www.redhat.com/archives/libvir-list/2015-March/msg01088.html
Patch 5 in that series supports <cmdline> for HVM guests, but only if
LIBXL_HAVE_BUILDINFO_KERNEL is defined (introduced in Xen4.5 IIRC). Do
we need to populate both b_info->extra_hvm and b_info->cmdline?
No. See above.
Wei.
Regards,
Jim