From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: The SMP RHEL 5.1 PAE guest can't boot up issue Date: Tue, 04 Mar 2008 13:38:16 +0200 Message-ID: <47CD34A8.6080107@qumranet.com> References: <200802221657.34243.sheng.yang@intel.com> <47BEF550.8040803@qumranet.com> <10EA09EFD8728347A513008B6B0DA77A02CFD373@pdsmsx411.ccr.corp.intel.com> <47C3E9B1.7040406@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net To: "Dong, Eddie" Return-path: In-Reply-To: <47C3E9B1.7040406@qumranet.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Avi Kivity wrote: > Dong, Eddie wrote: >>>> I don't know if the patch was still needed now, since it was posted >>>> long ago(I don't know which issue it solved). I'd like to post a >>>> revert patch if necessary. >>>> >>> I believe the patch is still necessary, since we still need to >>> guarantee that a vcpu's tsc is monotonous. I think there are three >>> issues to be addressed: >>> >>> 1. The majority of intel machines don't need the offset adjustment >>> since they already have a constant rate tsc that is synchronized on >>> all cpus. I think this is indicated by X86_FEATURE_CONSTANT_TSC >>> (though I'm not 100% certain if it means that the rate is the same >>> for all cpus, Thomas can you clarify?) >>> >> >> So why not make the TSC_OFFSET adjustment conditional? >> > > Yes, that's what I meant. We just need to be sure that this is what > X86_FEATURE_CONSTANT_TSC means. I changed tsc offset adjustment to only allow forward adjustment. Since hosts with synced tsc never require positive adjustment, they should now have better quality tsc. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/