From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH RFC] KVM: MMU: Don't use RCU for lockless shadow walking Date: Tue, 24 Apr 2012 12:23:35 +0300 Message-ID: <4F967117.4010509@redhat.com> References: <1335197812-32064-1-git-send-email-avi@redhat.com> <4F964A2C.7050106@linux.vnet.ibm.com> <4F96703F.4000607@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org To: Xiao Guangrong Return-path: Received: from mx1.redhat.com ([209.132.183.28]:23744 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756568Ab2DXJXj (ORCPT ); Tue, 24 Apr 2012 05:23:39 -0400 In-Reply-To: <4F96703F.4000607@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 04/24/2012 12:19 PM, Avi Kivity wrote: > > We need a mb here to avoid that setting vcpu->mode is reordered to the head > > of reading/writing spte? (it is safe on x86, but we need a comment at least?) > > I don't think so. Documentation/memory-barriers says: > > Any atomic operation that modifies some state in memory and returns > information > But we have some non-atomic writes to sptes. Will fix. -- error compiling committee.c: too many arguments to function