Re: [PATCH V2 1/3] Xen: Add support for qemu command-line passthrough

On 8/5/20 12:13 AM, 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 adds a 'xen' namespace extension, similar to the QEMU and > bhyve drivers, to map arbitrary arguments to the 'extra' member. Only > passthrough of arguments is supported. Passthrough of environment > variables or capabilities adjustments is not supported. > > Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt; > --- >   docs/drvxen.html.in           | 29 ++++++++++++ >   docs/schemas/domaincommon.rng | 17 +++++++ >   src/libxl/libxl_conf.c        | 10 ++++- >   src/libxl/libxl_conf.h        |  8 ++++ >   src/libxl/libxl_domain.c      | 84 +++++++++++++++++++++++++++++++++++ >   src/libxl/libxl_domain.h      |  1 + >   6 files changed, 148 insertions(+), 1 deletion(-) > > diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c > index d9fcde4364..f6bc8211b3 100644 > --- a/src/libxl/libxl_domain.c > +++ b/src/libxl/libxl_domain.c > +static int > +libxlDomainDefNamespaceParse(xmlXPathContextPtr ctxt, > +                             void **data) > +{ > +    libxlDomainXmlNsDefPtr nsdata = NULL; > +    g_autofree xmlNodePtr *nodes = NULL; > +    ssize_t nnodes; > +    size_t i; > +    int ret = -1; > + > +    if ((nnodes = virXPathNodeSet("./xen:commandline/xen:arg", ctxt, &nodes)) > < 0) > +        return -1; > + > +    if (nnodes == 0) > +        return 0; > + > +    nsdata = g_new0(libxlDomainXmlNsDef, 1); > +    nsdata->args = g_new0(char *, nnodes + 1); > + > +    for (i = 0; i < nnodes; i++) { > +        if (!(nsdata->args[nsdata->num_args++] = virXMLPropString(nodes[i], > "value"))) { > +            virReportError(VIR_ERR_INTERNAL_ERROR, "%s", > +                           _("No device model command-line argument > specified")); > +            goto cleanup; > +        } > +    } > + > +    if (nsdata->num_args > 0) > +        *data = g_steal_pointer(&nsdata); This if () looks redundant to me. The for-loop above in combination with nnodes = 0 check ensures that num_args is greater than zero here.