On 04.02.2026 08:49, Roger Pau Monné wrote: > On Fri, Jan 09, 2026 at 06:07:48AM -0800, [email protected] wrote: >> --- a/xen/include/public/xen.h >> +++ b/xen/include/public/xen.h >> @@ -608,6 +608,11 @@ DEFINE_XEN_GUEST_HANDLE(mmuext_op_t); >> /* DOMID_INVALID is used to identify pages with unknown owner. */ >> #define DOMID_INVALID xen_mk_uint(0x7FF4) >> >> +#if defined(__XEN__) || defined(__XEN_TOOLS__) >> +/* Domain ID allocator: search [1..DOMID_FIRST_RESERVED-1] range. */ >> +#define DOMID_ANY xen_mk_uint(0x7FF5) >> +#endif > > I would attempt to word the comment in a more generic way. While this > is now only used for the domain ID allocator, it's likely to gain more > uses going forward (Juergen already expressed interest): > > "DOMID_ANY is used to signal no specific domid requested. Handler > should pick a valid domid, or handle it as a broadcast value depending > on the context."
+1 > Also, I would remove the tools guards, I think once a DOMID_ constant > is allocated it becomes part of the public ABI, and it cannot be > withdrawn. See for example DOMID_IDLE: it's only used internally in > the hypervisor AFAICT, yet the define is fully visible in the > headers. It was me to ask for it to be guarded like this. DOMID_IDLE (and perhaps others) not being guarded (at least for IDLE: by just __XEN__) imo was a mistake. That mistake may in fact be correctable, if we could prove that the ID cannot usefully be passed into anywhere. Jan
