Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752290Ab0H0XoI (ORCPT ); Fri, 27 Aug 2010 19:44:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:27566 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751893Ab0H0XoH (ORCPT ); Fri, 27 Aug 2010 19:44:07 -0400 Message-ID: <4C784DB8.5090105@redhat.com> Date: Fri, 27 Aug 2010 13:43:52 -1000 From: Zachary Amsden User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.10) Gecko/20100621 Fedora/3.0.5-1.fc13 Thunderbird/3.0.5 MIME-Version: 1.0 To: Jan Kiszka CC: kvm@vger.kernel.org, Avi Kivity , Marcelo Tosatti , Glauber Costa , Thomas Gleixner , John Stultz , linux-kernel@vger.kernel.org Subject: Re: [KVM timekeeping 13/35] Perform hardware_enable in CPU_STARTING callback References: <1282291669-25709-1-git-send-email-zamsden@redhat.com> <1282291669-25709-14-git-send-email-zamsden@redhat.com> <4C77E89E.3040106@siemens.com> In-Reply-To: <4C77E89E.3040106@siemens.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1410 Lines: 35 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.... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/