Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758396AbaGDLIN (ORCPT ); Fri, 4 Jul 2014 07:08:13 -0400 Received: from thoth.sbs.de ([192.35.17.2]:57519 "EHLO thoth.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752962AbaGDLIL (ORCPT ); Fri, 4 Jul 2014 07:08:11 -0400 Message-ID: <53B68B07.8020509@siemens.com> Date: Fri, 04 Jul 2014 13:07:51 +0200 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Paolo Bonzini , Wanpeng Li , Bandan Das CC: Gleb Natapov , Hu Robert , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] KVM: nVMX: Fix IRQs inject to L2 which belong to L1 since race References: <1404284054-51863-1-git-send-email-wanpeng.li@linux.intel.com> <53B3CA6A.4050902@siemens.com> <20140703065955.GA4236@kernel> <20140704025250.GA2849@kernel> <53B63EF2.6000800@siemens.com> <53B674CD.2090906@siemens.com> <53B67602.4040604@redhat.com> <53B68781.9080200@siemens.com> In-Reply-To: <53B68781.9080200@siemens.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014-07-04 12:52, Jan Kiszka wrote: > On 2014-07-04 11:38, Paolo Bonzini wrote: >> Il 04/07/2014 11:33, Jan Kiszka ha scritto: >>> >>> The compiler is not aware of the fact that push/pop exists in this >>> function and, thus, places the vmcs parameter on the stack without >>> reserving the space. So the pushfq will overwrite the vmcs pointer and >>> let the function fail. >> >> Is that just a missing "memory" clobber? push/pop clobbers memory. > > Nope, we would needs some clobber like "stack". I wonder what is > required to use push in inline assembly safely? My colleague just found the answer: -mno-red-zone is required for 64-bit in order to play freely with the stack (or you need to stay off that zone, apparently some 128 bytes below the stack pointer). The kernel sets that switch, our unit tests do not. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux -- 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/