Zachary Amsden wrote: > On 08/27/2010 06:32 AM, Jan Kiszka wrote: >> Zachary Amsden wrote: >> >>> The CPU_STARTING callback was added upstream with the intention >>> of being used for KVM, specifically for the hardware enablement >>> that must be done before we can run in hardware virt. It had >>> bugs on the x86_64 architecture at the time, where it was called >>> after CPU_ONLINE. The arches have since merged and the bug is >>> gone. >>> >> What bugs are you referring to, or since which kernel version is >> CPU_STARTING usable for KVM? I need to encode this into kvm-kmod. >> > > Prior to the x86_64 / i386 merge, CPU_STARTING didn't work the same way > / exist in the x86_64 code... most of this is historical guesswork. At > some point, the 32/64 versions of the code in smpboot.c got merged and > now it does. > > Binary searching around my tree shows this timeframe: > > 2.6.11? - 2.6.23 : silver age ; i386 and x86_64 merge underway > | > 2.6.24 : bronze age ; i386 and x86_64 deprecated > | > 2.6.26 : iron age; smpboot_32.c / smpboot_64.c merge > \ > 2.6.28 : CPU_STARTING exists and first used > > /me scratches head wondering how this affects operation on older kernels.... I basically need to revert your patch on host kernels without CPU_STARTING and also on those where it might be broken. So I will set the barrier to 2.6.28 then. Thanks, Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
