Hi Henry, On 08/03/2024 03:05, Henry Wang wrote: > Hi everyone, > > On 2/26/2024 6:43 PM, Michal Orzel wrote: >>>>> xen/arch/arm/smpboot.c | 6 +++++- >>>>> 1 file changed, 5 insertions(+), 1 deletion(-) >>>>> >>>>> + /* PE not implemented using a multithreading type approach. */ >>>>> + if ( system_cpuinfo.mpidr.mt == 0 ) >>>> Do we need this check? It mt was true, cpu_sibling_mask would be incorrect >>>> anyway (it would still be 1). >>> I added this check for playing safe, because I only want to do the correct >>> thing >>> in this patch and avoid make things worse for MT case. With this patch, >>> non-MT >>> case can be improved and the MT case is remain unchanged. >>> >>> But I agree with you, and I would be more than happy if I can run a MT >>> setup and >>> finish the "else" part with this patch or follow-ups. Do you know maybe >>> qemu can >>> allow me to emulate a MT setup so that I can fix it properly in v2? Thanks! >> A65 is the only Arm CPU with SMT and I'm not aware of Qemu being able to >> emulate it. >> AFAICT, in Xen on Arm we assume no SMT, hence my question about your check. >> With or without it, >> some parts would still be incorrect (like cpu_sibling_mask), so what's the >> point in having a partial check. >> I would keep your solution without the check. Others may have a different >> opinion though. > > Since there isn't much discussion followed-up in this thread, I am > wondering do we have more inputs/opinions on this topic? If everyone > agrees, I've followed Michal's suggestion in v2 [1]. I clearly forgot to say in v2 that I'm ok with this change, so: Reviewed-by: Michal Orzel <michal.or...@amd.com>
~Michal
