On Tue, Mar 26, 2024 at 05:06:50PM +0000, Anthony PERARD wrote:
> On Tue, Mar 05, 2024 at 08:12:29PM +0100, Marek Marczykowski-Górecki wrote:
> > diff --git a/hw/xen/xen-legacy-backend.c b/hw/xen/xen-legacy-backend.c
> > index 124dd5f3d6..6bd4e6eb2f 100644
> > --- a/hw/xen/xen-legacy-backend.c
> > +++ b/hw/xen/xen-legacy-backend.c
> > @@ -603,6 +603,20 @@ static void xen_set_dynamic_sysbus(void)
> > machine_class_allow_dynamic_sysbus_dev(mc, TYPE_XENSYSDEV);
> > }
> >
> > +static bool xen_check_stubdomain(void)
> > +{
> > + char *dm_path = g_strdup_printf("/local/domain/%d/image", xen_domid);
> > + int32_t dm_domid;
> > + bool is_stubdom = false;
> > +
> > + if (!xenstore_read_int(dm_path, "device-model-domid", &dm_domid)) {
> > + is_stubdom = dm_domid != 0;
> > + }
> > +
> > + g_free(dm_path);
> > + return is_stubdom;
> > +}
> > +
> > void xen_be_init(void)
> > {
> > xenstore = qemu_xen_xs_open();
> > @@ -616,6 +630,8 @@ void xen_be_init(void)
> > exit(1);
> > }
> >
> > + xen_is_stubdomain = xen_check_stubdomain();
>
> This isn't really a backend specific information, and xen_be_init() is
> all about old backend implementation support. (qdisk which have been the
> first to be rewritten doesn't need xen_be_init(), or shouldn't). Could
> we move the initialisation elsewhere?I can try to move it, sure. > Is this relevant PV guests? If not, we could move the initialisation to > xen_hvm_init_pc(). > > Also, avoid having xen_check_stubdomain() depending on > "xen-legacy-backend", if possible. > > (In xen_hvm_init_pc(), a call to xen_register_ioreq() opens another > xenstore, as `state->xenstore`.) And xen_register_ioreq() calls xen_be_init() anyway, so it wouldn't change much in practice (at least for now)... > (There's already been effort to build QEMU without legacy backends, that > stubdom check would break in this scenario.) -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab
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