From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] KVM: VMX: Do not overwrite vcpu->srcu_idx in vmx_vcpu_reset Date: Thu, 14 Mar 2013 16:11:35 +0100 Message-ID: <5141E8A7.4090003@siemens.com> References: <5141E41B.8080804@siemens.com> <20130314150004.GX11223@redhat.com> <5141E6BA.2060404@siemens.com> <5141E7FA.8060003@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , Marcelo Tosatti , kvm To: Paolo Bonzini Return-path: Received: from thoth.sbs.de ([192.35.17.2]:21894 "EHLO thoth.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756635Ab3CNPLj (ORCPT ); Thu, 14 Mar 2013 11:11:39 -0400 In-Reply-To: <5141E7FA.8060003@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2013-03-14 16:08, Paolo Bonzini wrote: > Il 14/03/2013 16:03, Jan Kiszka ha scritto: >>>> vcpu->srcu_idx = srcu_read_lock() >>>> idx = srcu_read_lock(&vcpu->kvm->srcu); >>>> srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); >>>> vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); >>>> srcu_read_unlock(&vcpu->kvm->srcu, idx); >>>> srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); >>>> >>>> Not sure this is valid. >> Grmbl, likely not. > > It might be. > > Isn't it the same as two different CPUs doing > > CPU 1 CPU 2 > ------------------------------------------------------------------------------------------------ > > vcpu->srcu_idx = srcu_read_lock() > idx = srcu_read_lock(&vcpu->kvm->srcu); > srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); > vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); > srcu_read_unlock(&vcpu->kvm->srcu, idx); > srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx); > > ? Isn't there any per-cpu info encoded in idx? Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux