Balbir Singh <bsinghar...@gmail.com> writes: > On Mon, 29 May 2017 11:53:10 +1000 > Michael Ellerman <m...@ellerman.id.au> wrote: > >> We are running low on CPU feature bits, so we only want to use them when >> it's really necessary. >> >> CPU_FTR_SUBCORE is only used in one place, and only in C, so we don't >> need it in order to make asm patching work. It can only be set on >> "Power8" CPUs, which in practice means POWER8, POWER8E and POWER8NVL. >> There are no plans to implement it on future CPUs, but if there ever >> were we could retrofit it then. >> >> Although KVM uses subcores, it never looks at the CPU feature, it either >> looks at the ISA level or the threads_per_subcore value. >> >> So drop the CPU feature and do a PVR check instead. Drop the device tree >> "subcore" feature as we no longer support doing anything with it, and we >> will drop it from skiboot too. >> >> Signed-off-by: Michael Ellerman <m...@ellerman.id.au> >> --- > > Acked-by: Balbir Singh <bsinghar...@gmail.com> > > I looked at CPU_FTR_DBELL and its used for initialization and in > arch_show_interrupts(), no assembly
But the other criteria is that there is a small set of CPUs where it can be enabled, so that the PVR check is not horrible. I don't think DBELL fits that, I see it enabled for at least Power8, Power8E, Power9, e6500, e5500, e500mc. cheers
