Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751357AbaALTk0 (ORCPT ); Sun, 12 Jan 2014 14:40:26 -0500 Received: from mail-lb0-f172.google.com ([209.85.217.172]:62326 "EHLO mail-lb0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750999AbaALTkX (ORCPT ); Sun, 12 Jan 2014 14:40:23 -0500 MIME-Version: 1.0 In-Reply-To: <20140111122723.GA11475@amt.cnet> References: <1388654051-5968-1-git-send-email-chen.fan.fnst@cn.fujitsu.com> <20140108211009.GD20624@amt.cnet> <20140108232527.GA17874@amt.cnet> <20140109184711.GB2309@amt.cnet> <20140111122723.GA11475@amt.cnet> Date: Sun, 12 Jan 2014 14:40:21 -0500 Message-ID: Subject: Re: [PATCH] kvm: x86: Fix debug typo error in lapic From: Hu Yaohui To: Marcelo Tosatti Cc: kvm , "linux-kernel@vger.kernel.org" , Chen Fan , gleb@redhat.com, Paolo Bonzini Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thank you Marcelo! I really appreciate your explanation. On Sat, Jan 11, 2014 at 7:27 AM, Marcelo Tosatti wrote: > On Thu, Jan 09, 2014 at 03:08:25PM -0500, Hu Yaohui wrote: >> Hi Marcelo, >> Thanks for your replying! >> I hope you have a good day! I am sorry that it's not that obvious to >> me after I checked that function. >> If the remote vcpu is not in the same pcpu as the sender which calls >> kvm_vpcu_kick. >> Before the remote vcpu received the Host-IPI, it could be in guest >> mode which could possibly access the stale tlb entry that have been >> modifed by the sender. >> >> For smp_call_function_wait, the wait parameter will only let the >> sender side wait until the function has been executed on all the >> target cpus, then return. >> For TLB Flush IPI, the sender has already invalidate one tlb entry, >> the received side should get the IPI ASAP to invalidate the specified >> tlb before it's accessed, or there should have some mechanisms to >> enusre that even the stale tlb entry is accessed, it's still ok. I am >> not sure what's the situation here after I reviewed all the source >> codes. > > The sender only considers the TLB entry (or entries) flushed when > smp_call_function_wait finishes, that is when the receiver cpu acknowledges > it has flushed its TLB. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/