Am 15.06.2015 um 17:49 schrieb Peter Maydell: > On 15 June 2015 at 16:36, Alex Züpke <alexander.zue...@hs-rm.de> wrote: >> So this is the way to go: >> >> --- a/target-arm/translate.c >> +++ b/target-arm/translate.c >> @@ -4084,6 +4084,7 @@ static void gen_nop_hint(DisasContext *s, int val) >> gen_set_pc_im(s, s->pc); >> s->is_jmp = DISAS_WFI; >> break; >> + case 1: /* yield */ >> case 2: /* wfe */ >> gen_set_pc_im(s, s->pc); >> s->is_jmp = DISAS_WFE; > > Actually I want to split out the yield code path from the wfe > one, because some day we may actually implement WFE as WFE, > at which point WFE has some trap-to-EL2 logic that YIELD > doesn't. I was about to write a patch to do that...
OK. Both the cpu_exit-after-sending-IPI or the YIELD patch would fix my issue, but I think the YIELD one fits better. I updated my testcase to YIELD during polling: http://www.cs.hs-rm.de/~zuepke/qemu/ipi_yield.elf 3174 bytes, md5sum e74897e6b6d70f472db9e9d657780035 > (If you plan to run your custom OS under a hypervisor you > might prefer SEV/WFE over YIELD, because then if your custom OS > is under heavy load the hypervisor has a chance to swap this > vcpu out and run some other one.) > > thanks > -- PMM > Thanks for the hint! Best regards Alex
