From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC][PATCH] qemu-kvm: Introduce writeback scope for cpu_synchronize_state Date: Wed, 18 Nov 2009 15:48:35 +0200 Message-ID: <4B03FB33.3070408@redhat.com> References: <4B018542.3020602@siemens.com> <4B01A487.3020808@redhat.com> <4B01C2B0.3000205@web.de> <4B02592C.6060004@redhat.com> <4B025B50.4070505@web.de> <4B0260D7.1060107@redhat.com> <4B026A03.4080600@web.de> <4B0298F0.3080007@redhat.com> <4B029FA8.5080205@web.de> <4B02A4FD.4010802@redhat.com> <4B02AF58.4010407@web.de> <4B02B252.5080207@redhat.com> <4B02D444.6080402@web.de> <4B02D635.6070805@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm , Gleb Natapov To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60291 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756921AbZKRNsd (ORCPT ); Wed, 18 Nov 2009 08:48:33 -0500 In-Reply-To: <4B02D635.6070805@web.de> Sender: kvm-owner@vger.kernel.org List-ID: On 11/17/2009 06:58 PM, Jan Kiszka wrote: > >> That wouldn't be required anymore with the "always queue" policy. >> > Hmm, unless we need mp_state manipulation analogously to KVM_NMI vs. > KVM_SET_VCPU_STATE: The former will queue, the latter write, but may be > overwritten by anything queued. If you just queue KVM_SET_MP_STATE, you > still have a conflict between concurrent manipulations from user space, > something we want to resolve automagically. > The idea is to queue. But queueing INIT state clears the queue (we're pretending to send an INIT signal over the apic bus). -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.