From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753271AbaGHIAl (ORCPT ); Tue, 8 Jul 2014 04:00:41 -0400 Received: from mail-qc0-f169.google.com ([209.85.216.169]:46794 "EHLO mail-qc0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751842AbaGHIAk (ORCPT ); Tue, 8 Jul 2014 04:00:40 -0400 Message-ID: <53BBA523.4080006@redhat.com> Date: Tue, 08 Jul 2014 10:00:35 +0200 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Jan Kiszka , Bandan Das , kvm@vger.kernel.org CC: linux-kernel@vger.kernel.org, Wanpeng Li , Gleb Natapov Subject: Re: [PATCH] KVM: x86: Check for nested events if there is an injectable interrupt References: <53BB86C2.9040805@redhat.com> <53BB9638.6040803@siemens.com> In-Reply-To: <53BB9638.6040803@siemens.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 08/07/2014 08:56, Jan Kiszka ha scritto: > I don't think arch.nmi_pending can flip asynchronously, only in the > context of the VCPU thread - in contrast to pending IRQ states. Right, only nmi_queued is changed from other threads. /me should really look at the code instead of going from memory. >> Jan, what do you think? Can you run Jailhouse through this patch? > > Jailhouse seems fine with it, and it resolves the lockup of nested KVM > here as well. Thinking more about it, I think this is the right fix. Not setting KVM_REQ_EVENT in some cases can be an optimization, but it's not necessary. Definitely there are other cases in which KVM_REQ_EVENT is set even though no event is pending---most notably during emulation of invalid guest state. Paolo