RE: [PATCH v6 00/18] xen: introduce CONFIG_SYSCTL

["Penny, Zheng" <penny.zheng@xxxxxxx>]

[Public]

> -----Original Message-----
> From: Jan Beulich <jbeulich@xxxxxxxx>
> Sent: Friday, July 4, 2025 5:49 PM
> To: Penny, Zheng <penny.zheng@xxxxxxx>
> Cc: Huang, Ray <Ray.Huang@xxxxxxx>; Andrew Cooper
> <andrew.cooper3@xxxxxxxxxx>; Anthony PERARD <anthony.perard@xxxxxxxxxx>;
> Orzel, Michal <Michal.Orzel@xxxxxxx>; Julien Grall <julien@xxxxxxx>; Roger Pau
> Monné <roger.pau@xxxxxxxxxx>; Stefano Stabellini <sstabellini@xxxxxxxxxx>; 
> Daniel
> P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>; Dario Faggioli <dfaggioli@xxxxxxxx>;
> Juergen Gross <jgross@xxxxxxxx>; George Dunlap <gwd@xxxxxxxxxxxxxx>;
> Nathan Studer <nathan.studer@xxxxxxxxxxxxxxx>; Stewart Hildebrand
> <stewart@xxxxxxx>; Bertrand Marquis <bertrand.marquis@xxxxxxx>; Volodymyr
> Babchuk <Volodymyr_Babchuk@xxxxxxxx>; Alistair Francis
> <alistair.francis@xxxxxxx>; Bob Eshleman <bobbyeshleman@xxxxxxxxx>;
> Connor Davis <connojdavis@xxxxxxxxx>; Oleksii Kurochko
> <oleksii.kurochko@xxxxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx; xen-
> devel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v6 00/18] xen: introduce CONFIG_SYSCTL
>
> On 04.07.2025 11:29, Penny Zheng wrote:
> > It can be beneficial for some dom0less systems to further reduce Xen
> > footprint via disabling some hypercalls handling code, which may not
> > to be used & required in such systems. Each hypercall has a separate
> > option to keep configuration flexible.
> >
> > Options to disable hypercalls:
> > - sysctl
> > - domctl
> > - hvm
> > - physdev
> > - platform
> >
> > This patch serie is only focusing on introducing CONFIG_SYSCTL.
> > Different options will be covered in different patch serie.
> >
> > Features, like LIVEPATCH, Overlay DTB, which fully rely on sysctl op,
> > will be wrapped with CONFIG_SYSCTL, to reduce Xen footprint as much as
> possible.
> >
> > It is derived from Stefano Stabellini's commit "xen: introduce kconfig
> > options to disable hypercalls"(
> > https://lore.kernel.org/xen-devel/20241219092917.3006174-1-Sergiy_Kibr
> > ik@xxxxxxxx)
> >
> > ---
> > Commit "xen/x86: remove "depends on !PV_SHIM_EXCLUSIVE"" and commit "
> > xen/sysctl: wrap around sysctl hypercall" shall be commited together.
> > ---
> > Penny Zheng (16):
> >   xen/xsm: wrap around xsm_sysctl with CONFIG_SYSCTL
> >   xen/sysctl: wrap around XEN_SYSCTL_readconsole
> >   xen/sysctl: make CONFIG_TRACEBUFFER depend on CONFIG_SYSCTL
> >   xen/sysctl: wrap around XEN_SYSCTL_sched_id
> >   xen/sysctl: wrap around XEN_SYSCTL_perfc_op
> >   xen/sysctl: wrap around XEN_SYSCTL_lockprof_op
> >   xen/pmstat: introduce CONFIG_PM_OP
> >   xen/sysctl: introduce CONFIG_PM_STATS
> >   xen/sysctl: wrap around XEN_SYSCTL_page_offline_op
> >   xen/sysctl: wrap around XEN_SYSCTL_cpupool_op
> >   xen/sysctl: wrap around XEN_SYSCTL_scheduler_op
> >   xen/sysctl: wrap around XEN_SYSCTL_physinfo
> >   xen/sysctl: make CONFIG_COVERAGE depend on CONFIG_SYSCTL
> >   xen/sysctl: make CONFIG_LIVEPATCH depend on CONFIG_SYSCTL
> >   xen/sysctl: wrap around arch-specific arch_do_sysctl
> >   xen/x86: remove "depends on !PV_SHIM_EXCLUSIVE"
> >
> > Stefano Stabellini (2):
> >   xen: introduce CONFIG_SYSCTL
> >   xen/sysctl: wrap around sysctl hypercall
>
> This doesn't look to be based on latest staging, where some of the changes 
> above
> are already present. I specifically tried to get some of the stuff in so that 
> the next
> re-posting wouldn't be as large.

Sorry, I'll rebase

>
> Jan