Michael Kelley <mikel...@microsoft.com> writes: > From: Vitaly Kuznetsov <vkuzn...@redhat.com> Sent: Wednesday, March 13, 2019 > 7:23 AM > >> >> > diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile >> >> > index be6e0fb..a887955 100644 >> >> > --- a/drivers/clocksource/Makefile >> >> > +++ b/drivers/clocksource/Makefile >> >> > @@ -83,3 +83,4 @@ obj-$(CONFIG_ATCPIT100_TIMER) += >> >> > timer-atcpit100.o >> >> > obj-$(CONFIG_RISCV_TIMER) += timer-riscv.o >> >> > obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o >> >> > obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o >> >> > +obj-$(CONFIG_HYPERV) += hyperv_syntimer.o >> >> >> >> (just a couple of spare thoughs) >> >> >> >> CONFIG_HYPERV can also be a module, are we OK with that? (we'll have to >> >> support module loading/unloading then and honestly I see no reason for >> >> that. I would prefer everything but VMBus devices to be in >> >> kernel.) If we don't want it to be a module we can create a hidden >> >> CONFIG_HYPERV_STIMER or something like that - just like we already do >> >> for CONFIG_HYPERV_TSCPAGE. >> >> >> >> There is, however, one additional dependency here: when running in >> >> non-direct mode, Hyper-V clockevent devices require functional Hyper-V >> >> messaging - which currently lives in VMBus code so that may explain why >> >> you may want to keep stimer code in the same entity. Or, alternatively, >> >> we can move Hyper-V messaging out of VMBus code (is it actually >> >> architecture-agnostic?) >> >> >> > >> > I thought about introducing CONFIG_HYPERV_STIMER, but in my >> > judgment it was just unnecessary complexity. The Hyper-V clocksource >> > driver can't exist independent of Hyper-V, and vice versa. When both the >> > clocksource and clockevents code is considered, the VMbus driver and >> > Hyper-V initialization code has to call directly into the driver since the >> > Hyper-V synthetic timers and reference time counter aren't independently >> > enumerated. Even if we could get the Hyper-V messaging out of VMbus >> > code, we would still need the clocksource initialization call directly from >> > hyperv_init(), which is not in a module (see the 2nd patch of the series). >> > >> >> Right, so hv_init_clocksource() cannot live in hv_vmbus module and we >> need to somehow prevent hyperv_syntimer.o from going in there. And >> >> +obj-$(CONFIG_HYPERV) += hyperv_syntimer.o >> >> will do exactly the opposite - put it in hv_vmbus module. Or am I >> missing something? (I haven't tried to build your code yet, sorry). >> > > That line just controls whether hyperv_syntimer.o is built. It doesn't put > it in the hv_vmbus module. All of the clocksource .o files that are built go > into the kernel, not in a module. But thinking about it more, the above works > correctly when CONFIG_HYPERV=y, but not when CONFIG_HYPERV=m.
Yes, that's what I meant. > I'll have to introduce CONFIG_HYPERV_TIMER after all. Will fix this in v2. > Thanks > for the discussion! Thanks! -- Vitaly
