From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753774Ab1K0KuI (ORCPT ); Sun, 27 Nov 2011 05:50:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34995 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751270Ab1K0KuH (ORCPT ); Sun, 27 Nov 2011 05:50:07 -0500 Date: Sun, 27 Nov 2011 12:50:00 +0200 From: Gleb Natapov To: Avi Kivity Cc: Liu Ping Fan , aliguori@us.ibm.com, kvm@vger.kernel.org, qemu-devel@nongnu.org, linux-kernel@vger.kernel.org, ryanh@us.ibm.com, jan.kiszka@web.de Subject: Re: [Qemu-devel] [PATCH 2/2] kvm: exit to userspace with reason KVM_EXIT_VCPU_DEAD Message-ID: <20111127105000.GL2557@redhat.com> References: <1322188529-11609-1-git-send-email-kernelfans@gmail.com> <1322361735-21428-1-git-send-email-kernelfans@gmail.com> <4ED212C7.1080901@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ED212C7.1080901@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 27, 2011 at 12:36:55PM +0200, Avi Kivity wrote: > On 11/27/2011 04:42 AM, Liu Ping Fan wrote: > > From: Liu Ping Fan > > > > The vcpu can be safely released when > > --1.guest tells us that the vcpu is not needed any longer. > > --2.vcpu hits the last instruction _halt_ > > > > If both of the conditions are satisfied, kvm exits to userspace > > with the reason vcpu dead. So the user thread can exit safely. > > > > > > Seems to be completely unnecessary. If you want to exit from the vcpu > thread, send it a signal. > Also if guest "tells us that the vcpu is not needed any longer" (via ACPI I presume) and vcpu actually doing something critical instead of sitting in 1:hlt; jmp 1b loop then it is guest's problem if it stops working after vcpu destruction. -- Gleb.