From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1756168Ab1LGNkz (ORCPT <rfc822;w@1wt.eu>);
	Wed, 7 Dec 2011 08:40:55 -0500
Received: from mx1.redhat.com ([209.132.183.28]:20023 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1755801Ab1LGNku (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Wed, 7 Dec 2011 08:40:50 -0500
Date: Wed, 7 Dec 2011 11:39:47 -0200
From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: Raghavendra K T <raghukt@linux.vnet.ibm.com>,
        Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
        Greg Kroah-Hartman <gregkh@suse.de>, KVM <kvm@vger.kernel.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Virtualization <virtualization@lists.linux-foundation.org>,
        Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, Dave Jiang <dave.jiang@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
        Gleb Natapov <gleb@redhat.com>, Yinghai Lu <yinghai@kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Rik van Riel <riel@redhat.com>,
        Xen <xen-devel@lists.xensource.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Sasha Levin <levinsasha928@gmail.com>,
        Suzuki Poulose <suzuki@linux.vnet.ibm.com>,
        Dave Hansen <dave@linux.vnet.ibm.com>
Subject: Re: [PATCH RFC V3 2/4] kvm hypervisor : Add a hypercall to KVM
 hypervisor to support pv-ticketlocks
Message-ID: <20111207133947.GA1708@amt.cnet>
References: <20111130085921.23386.89708.sendpatchset@oc5400248562.ibm.com>
 <20111130085959.23386.69166.sendpatchset@oc5400248562.ibm.com>
 <20111207104849.GA24849@amt.cnet>
 <4EDF5413.1030107@linux.vnet.ibm.com>
 <20111207123330.GA32212@amt.cnet>
 <4EDF6049.2030204@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4EDF6049.2030204@redhat.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, Dec 07, 2011 at 02:47:05PM +0200, Avi Kivity wrote:
> On 12/07/2011 02:33 PM, Marcelo Tosatti wrote:
> > > 
> > > Also Avi pointed that, logically kvm_arch_vcpu_ioctl_set_mpstate should
> > > be called only in vcpu thread, so after further debugging, I noticed
> > > that,  setting vcpuN->mp_state = KVM_MP_STATE_RUNNABLE; is not
> > > necessary.
> > > I 'll remove that in the next patch. Thanks for pointing.
> >
> > In fact you don't need kvm_arch_vcpu_ioctl_set_mpstate either, only the
> > new "kicked" flag.
> 
> If we have a kicked flag, it becomes necessary to live migrate it.
> 
> Maybe we can change KVM_GET_MP_STATE to fold the kicked flag into the mp
> state (converting HALTED into RUNNABLE).

Yep, that works.

> Also I think we can keep the kicked flag in vcpu->requests, no need for
> new storage.

Was going to suggest it but it violates the currently organized
processing of entries at the beginning of vcpu_enter_guest.

That is, this "kicked" flag is different enough from vcpu->requests
processing that a separate variable seems worthwhile (even more
different with convertion to MP_STATE at KVM_GET_MP_STATE).