On 02/05/2023 8:17 am, Jan Beulich wrote: > The hook being able to deny access to data for certain domains means > that no caller can assume to have a system-wide picture when holding the > results. > > Wouldn't it make sense to permit the function to merely "count" domains? > While racy in general (including in its present, "normal" mode of > operation), within a tool stack this could be used as long as creation > of new domains is suppressed between obtaining the count and then using > it.
This would not be the first example of the XSM hooks being tantamount to useless. I doubt it will be the last either. With the rest of Alejandro's series in place, all requests for a single domid's worth of info use the domctl, and all requests for all domains use the systctl. As a result, we can retrofit some sanity and change the meaning of the XSM hook here for the sysctl, to mean "can see a systemwide view" (or not). This moves the check out of the loop, and fixes the behaviour. ~Andrew
