From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752422AbdKJKIo (ORCPT ); Fri, 10 Nov 2017 05:08:44 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:60619 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751163AbdKJKIm (ORCPT ); Fri, 10 Nov 2017 05:08:42 -0500 Date: Fri, 10 Nov 2017 11:08:38 +0100 From: Peter Zijlstra To: Wanpeng Li Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini , Radim Kr??m???? , Wanpeng Li Subject: Re: [PATCH v3 4/4] KVM: Add flush_on_enter before guest enter Message-ID: <20171110100838.eqfccs735x4ghw6q@hirez.programming.kicks-ass.net> References: <1510307387-14812-1-git-send-email-wanpeng.li@hotmail.com> <1510307387-14812-5-git-send-email-wanpeng.li@hotmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1510307387-14812-5-git-send-email-wanpeng.li@hotmail.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 10, 2017 at 01:49:47AM -0800, Wanpeng Li wrote: > @@ -2887,7 +2899,7 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu) > if (!(vcpu->arch.st.msr_val & KVM_MSR_ENABLED)) > return; > > - vcpu->arch.st.steal.preempted = KVM_VCPU_PREEMPTED; > + vcpu->arch.st.steal.preempted |= KVM_VCPU_PREEMPTED; I don't understand this one... If there is concurrency its wrong, if there is no concurrency it still doesn't make sense as there should not be any FLUSH flags to preserve.. > > kvm_write_guest_offset_cached(vcpu->kvm, &vcpu->arch.st.stime, > &vcpu->arch.st.steal.preempted,