From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] cpu: smp_wmb before lauching cpus. Date: Thu, 05 Jul 2012 12:16:40 +0200 Message-ID: <4FF56988.8060207@siemens.com> References: <1341454689-8129-1-git-send-email-qemulist@gmail.com> <4FF53856.6030901@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: qemu-devel@nongnu.org, Anthony Liguori , kvm@vger.kernel.org To: liu ping fan Return-path: Received: from david.siemens.de ([192.35.17.14]:21860 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752950Ab2GEKQs (ORCPT ); Thu, 5 Jul 2012 06:16:48 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 2012-07-05 12:10, liu ping fan wrote: > On Thu, Jul 5, 2012 at 2:46 PM, Jan Kiszka wrote: >> On 2012-07-05 04:18, Liu Ping Fan wrote: >>> Vcpu state must be set completely before receiving INIT-IPI,SIPI >>> >>> Signed-off-by: Liu Ping Fan >>> --- >>> kvm.h | 1 + >>> 1 files changed, 1 insertions(+), 0 deletions(-) >>> >>> diff --git a/kvm.h b/kvm.h >>> index 9c7b0ea..5b3c228 100644 >>> --- a/kvm.h >>> +++ b/kvm.h >>> @@ -198,6 +198,7 @@ static inline void cpu_synchronize_post_init(CPUArchState *env) >>> { >>> if (kvm_enabled()) { >>> kvm_cpu_synchronize_post_init(env); >>> + smp_wmb(); >>> } >>> } >>> >>> >> >> In theory, there should be no vcpu kick-off after this without some >> locking operations involved that imply barriers. Did you see real > > Yeah, but what if it is non-x86? The locking I'm referring to is arch independent. >> inconsistencies without this explicit one? Again: Did you see real issues or is this based on static analysis? Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:59702) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Smj7D-0000VF-FB for qemu-devel@nongnu.org; Thu, 05 Jul 2012 06:16:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Smj78-0004fG-N8 for qemu-devel@nongnu.org; Thu, 05 Jul 2012 06:16:50 -0400 Received: from david.siemens.de ([192.35.17.14]:17280) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Smj78-0004f0-DL for qemu-devel@nongnu.org; Thu, 05 Jul 2012 06:16:46 -0400 Message-ID: <4FF56988.8060207@siemens.com> Date: Thu, 05 Jul 2012 12:16:40 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <1341454689-8129-1-git-send-email-qemulist@gmail.com> <4FF53856.6030901@web.de> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] cpu: smp_wmb before lauching cpus. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: liu ping fan Cc: qemu-devel@nongnu.org, Anthony Liguori , kvm@vger.kernel.org On 2012-07-05 12:10, liu ping fan wrote: > On Thu, Jul 5, 2012 at 2:46 PM, Jan Kiszka wrote: >> On 2012-07-05 04:18, Liu Ping Fan wrote: >>> Vcpu state must be set completely before receiving INIT-IPI,SIPI >>> >>> Signed-off-by: Liu Ping Fan >>> --- >>> kvm.h | 1 + >>> 1 files changed, 1 insertions(+), 0 deletions(-) >>> >>> diff --git a/kvm.h b/kvm.h >>> index 9c7b0ea..5b3c228 100644 >>> --- a/kvm.h >>> +++ b/kvm.h >>> @@ -198,6 +198,7 @@ static inline void cpu_synchronize_post_init(CPUArchState *env) >>> { >>> if (kvm_enabled()) { >>> kvm_cpu_synchronize_post_init(env); >>> + smp_wmb(); >>> } >>> } >>> >>> >> >> In theory, there should be no vcpu kick-off after this without some >> locking operations involved that imply barriers. Did you see real > > Yeah, but what if it is non-x86? The locking I'm referring to is arch independent. >> inconsistencies without this explicit one? Again: Did you see real issues or is this based on static analysis? Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux