Hi,
I am reviewing the existing code that sets has_dynamic_sysbus,
and this patch confused me. I have a question below:
On Tue, Nov 22, 2016 at 07:10:58AM +0100, Juergen Gross wrote:
> Create a qdev plugged to the xen-sysbus for each new backend device.
> This device can be used as a parent for all needed devices of that
> backend. The id of the new device will be "xen-<type>-<dev>" with
> <type> being the xen backend type (e.g. "qdisk") and <dev> the xen
> backend number of the type under which it is to be found in xenstore.
>
> Signed-off-by: Juergen Gross <jgr...@suse.com>
> Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
> ---
> hw/xen/xen_backend.c | 47
> ++++++++++++++++++++++++++++++++++++++++++++
> hw/xen/xen_pvdev.c | 4 +++-
> include/hw/xen/xen_backend.h | 4 ++++
> include/hw/xen/xen_pvdev.h | 1 +
> 4 files changed, 55 insertions(+), 1 deletion(-)
>
[...]
> +static void xen_set_dynamic_sysbus(void)
> +{
> + Object *machine = qdev_get_machine();
> + ObjectClass *oc = object_get_class(machine);
> + MachineClass *mc = MACHINE_CLASS(oc);
> +
> + mc->has_dynamic_sysbus = true;
> +}
> +
Why exactly is this code necessary? I assume there's no current
use case for "-device xen-sysdev" and "-device xen-backend",
correct? The devices created by C code like xen_be_get_xendev()
aren't supposed to be returned by
foreach_dynamic_sysbus_device().
> int xen_be_register(const char *type, struct XenDevOps *ops)
> {
> char path[50];
> @@ -562,6 +579,8 @@ int xen_be_register(const char *type, struct XenDevOps
> *ops)
>
> void xen_be_register_common(void)
> {
> + xen_set_dynamic_sysbus();
> +
> xen_be_register("console", &xen_console_ops);
> xen_be_register("vkbd", &xen_kbdmouse_ops);
> xen_be_register("qdisk", &xen_blkdev_ops);
[...]
--
Eduardo
