Re: [PATCH 2/4] Xen: Add support for qemu command-line passthrough

On a Friday in 2020, Jim Fehlig wrote: > Xen supports passing arbitrary arguments to the QEMU device model via > the 'extra' member of the public libxl_domain_build_info structure. > This patch uses QEMU namespace extensions already in place for the QEMU > driver to map arbitrary arguments to the 'extra' member. Only passthrough > of arguments is supported. Trying to pass environment variables or > capabilities adjustments is not supported and will result in an error. > > Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt; > --- > docs/drvxen.html.in      | 35 ++++++++++++++ > src/libxl/libxl_conf.c   | 11 ++++- > src/libxl/libxl_conf.h   |  8 ++++ > src/libxl/libxl_domain.c | 99 ++++++++++++++++++++++++++++++++++++++++ > src/libxl/libxl_domain.h |  1 + > 5 files changed, 153 insertions(+), 1 deletion(-) > > diff --git a/docs/drvxen.html.in b/docs/drvxen.html.in > index b2f41c1763..ffaf01fedb 100644 > --- a/docs/drvxen.html.in > +++ b/docs/drvxen.html.in > @@ -141,6 +141,41 @@ vnclisten = "0.0.0.0" > disk = [ "tap:aio:/var/lib/xen/images/rhel5pv.img,xvda,w", > "tap:qcow:/root/qcow1-xen.img,xvdd,w" ] > vif = [ "mac=00:16:3e:60:36:ba,bridge=virbr0,script=vif-bridge,vifname=vif5.0" > ]</pre> > > +    <h2><a id="xencommand">Pass-through of arbitrary command-line arguments > +    to the qemu device model</a></h2> > + > +    <p><span class="since">Since 6.7.0</span>, the Xen driver supports passing > +      arbitrary command-line arguments to the qemu device model used by Xen with > +      the <code>&lt;qemu:commandline&gt;</code> element under > <code>domain</code>. > +      In order to use command-line pass-through, an XML namespace request > must be > +      issued that pulls in > <code>http://libvirt.org/schemas/domain/qemu/1.0</code>;. IIUC the 'qemu' namespace prefix comes from the name of the 'qemu' driver, not the executable it invokes, so this should use 'libxl' or something unique.