From: Avi Kivity Subject: Re: [PATCH 1/7] KVM: VMX: Allocate MSR Bitmap for each vcpu Date: Wed, 08 Oct 2008 12:14:22 +0200 Message-ID: <48EC87FE.3060006@redhat.com> References: <1223439478-26515-1-git-send-email-sheng@linux.intel.com> <1223439478-26515-2-git-send-email-sheng@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Sheng Yang Return-path: Received: from mx2.redhat.com ([66.187.237.31]:50732 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751021AbYJHKOT (ORCPT ); Wed, 8 Oct 2008 06:14:19 -0400 In-Reply-To: <1223439478-26515-2-git-send-email-sheng@linux.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: Sheng Yang wrote: > Separate msr_bitmap for each vcpu, prepared for guest PAT support. > Why is this necessary? True, it reduces the overhead of the guest reading and writing the PAT MSRs, but is such access frequent? I would think guests set the PAT once, and never change it later. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.