From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757615Ab2EABEU (ORCPT ); Mon, 30 Apr 2012 21:04:20 -0400 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:51423 "EHLO e28smtp09.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757377Ab2EABET (ORCPT ); Mon, 30 Apr 2012 21:04:19 -0400 Message-ID: <4F9F367F.8090603@linux.vnet.ibm.com> Date: Tue, 01 May 2012 06:33:59 +0530 From: Raghavendra K T Organization: IBM User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.1) Gecko/20120216 Thunderbird/10.0.1 MIME-Version: 1.0 To: "Nikunj A. Dadhania" CC: peterz@infradead.org, mingo@elte.hu, jeremy@goop.org, mtosatti@redhat.com, kvm@vger.kernel.org, x86@kernel.org, vatsa@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, avi@redhat.com, hpa@zytor.com Subject: Re: [RFC PATCH v1 1/5] KVM Guest: Add VCPU running/pre-empted state for guest References: <20120427161727.27082.43096.stgit@abhimanyu> <20120427162314.27082.13703.stgit@abhimanyu> In-Reply-To: <20120427162314.27082.13703.stgit@abhimanyu> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit x-cbid: 12050101-2674-0000-0000-0000043A3440 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/27/2012 09:53 PM, Nikunj A. Dadhania wrote: > The patch adds guest code for msr between guest and hypervisor. The > msr will export the vcpu running/pre-empted information to the guest > from host. This will enable guest to intelligently send ipi to running > vcpus and set flag for pre-empted vcpus. This will prevent waiting for > vcpus that are not running. > > Suggested-by: Peter Zijlstra > Signed-off-by: Nikunj A. Dadhania > --- > arch/x86/include/asm/kvm_para.h | 10 ++++++++++ > arch/x86/kernel/kvm.c | 33 +++++++++++++++++++++++++++++++++ > 2 files changed, 43 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h > index 77266d3..f57b5cc 100644 > --- a/arch/x86/include/asm/kvm_para.h > +++ b/arch/x86/include/asm/kvm_para.h > @@ -24,6 +24,7 @@ > #define KVM_FEATURE_ASYNC_PF 4 > #define KVM_FEATURE_STEAL_TIME 5 > #define KVM_FEATURE_PV_UNHALT 6 > +#define KVM_FEATURE_VCPU_STATE 7 I think you intended to use KVM_FEATURE_VCPU_STATE to address guest/host compatibility issue so that host/guest does not break when one of them run older kernel?