Hi Jan, We're prototyping a future silicon feature that can crash the SoC if the OS schedules some legacy transactions on them. Hacking the OS to that extent is prohibitive, so our goal was to boot the system with the cores offline and then only bring them up in a vm/inmate with a restricted non-linux environment running in that inmate.
We're mostly trying to assess the size of the changes that would be required, and what the reasons were behind ignoring offline cores in the jailhouse init. -gavin On Tuesday, July 18, 2017 at 1:29:13 PM UTC-7, Jan Kiszka wrote: > On 2017-07-18 20:23, Randy Witt wrote: > > Is it possible for inmates to use cpus that are offline as far as Linux is > > concerned? > > > > For example, suppose I have 4 cores and I use "maxcpus=2" to prevent Linux > > from bringing cores 2,3 online. Can I still use those cores for an inmate? > > > > I know the jailhouse driver queries online cpus, and my experimentation > > says it currently doesn't work, but I wanted to verify. This is because I > > actually have a scenario where I need minimal poking of the core before the > > inmate code runs. > > > > Please accept my apologies if this has been asked before, I couldn't find > > an answer. > > > > Jailhouse needs to initialize itself on each CPU it is supposed to > manage. Therefore, its driver calls the init code on each of those CPUs. > Other CPUs will remain out of reach for it and, thus, also for inmates. > > Theoretically, it would be possible to extend Jailhouse to physically > bootstrap also offline CPUs without relying on Linux to hand them over > in a booted state. Practically, that would mean making the hypervisor > more complex. It would take a good use case to justify such an extension. > > Can you elaborate on the reasons? > > Jan -- You received this message because you are subscribed to the Google Groups "Jailhouse" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
