From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:45747)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <hutao@cn.fujitsu.com>) id 1TakmP-0006BU-C2
	for qemu-devel@nongnu.org; Tue, 20 Nov 2012 05:10:15 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <hutao@cn.fujitsu.com>) id 1TakmI-0004L5-D5
	for qemu-devel@nongnu.org; Tue, 20 Nov 2012 05:10:08 -0500
Received: from [222.73.24.84] (port=28531 helo=song.cn.fujitsu.com)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <hutao@cn.fujitsu.com>) id 1TakmH-0004Eh-VJ
	for qemu-devel@nongnu.org; Tue, 20 Nov 2012 05:10:02 -0500
Date: Tue, 20 Nov 2012 18:09:48 +0800
From: Hu Tao <hutao@cn.fujitsu.com>
Message-ID: <20121120100948.GB17311@localhost.localdomain>
References: <0a2274eccf1b1dd420f16359f7e1de74fa2f9fbe.1351131144.git.hutao@cn.fujitsu.com>
	<20121031011256.GC12325@amt.cnet> <50908354.5070608@cn.fujitsu.com>
	<CA+1xoqdcaeAm05_=rx3h9KHph+j7Ab8vRG_w9yUk7jtn+wHuBg@mail.gmail.com>
	<20121106015835.GA11971@localhost.localdomain>
	<CA+1xoqd60YihExEuSU2qzsyFRXLS=XaeeX9AaMLhPHggfM6V3A@mail.gmail.com>
	<20121113021908.GA8176@amt.cnet>
MIME-Version: 1.0
In-Reply-To: <20121113021908.GA8176@amt.cnet>
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Subject: Re: [Qemu-devel] [PATCH v11] kvm: notify host when the guest is
	panicked
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Andrew Jones <drjones@redhat.com>, kvm list <kvm@vger.kernel.org>, Jan Kiszka <jan.kiszka@siemens.com>, qemu-devel <qemu-devel@nongnu.org>, Gleb Natapov <gleb@redhat.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Blue Swirl <blauwirbel@gmail.com>, Avi Kivity <avi@redhat.com>, Luiz Capitulino <lcapitulino@redhat.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Sasha Levin <levinsasha928@gmail.com>

Hi Marcelo,

On Tue, Nov 13, 2012 at 12:19:08AM -0200, Marcelo Tosatti wrote:
> On Fri, Nov 09, 2012 at 03:17:39PM -0500, Sasha Levin wrote:
> > On Mon, Nov 5, 2012 at 8:58 PM, Hu Tao <hutao@cn.fujitsu.com> wrote:
> > > But in the case of panic notification, more dependency means more
> > > chances of failure of panic notification. Say, if we use a virtio device
> > > to do panic notification, then we will fail if: virtio itself has
> > > problems, virtio for some reason can't be deployed(neither built-in or
> > > as a module), or guest doesn't support virtio, etc.
> > 
> > Add polling to your virtio device. If it didn't notify of a panic but
> > taking more than 20 sec to answer your poll request you can assume
> > it's dead.
> > 
> > Actually, just use virtio-serial and something in userspace on the guest.
> 
> They want the guest to stop, so a memory dump can be taken by management
> interface.
> 
> Hu Tao, lets assume port I/O is the preferred method for communication.

Okey.

> Now, the following comments have still not been addressed:
> 
> 1) Lifecycle of the stopped guest and interaction with other stopped
> states in QEMU.

Patch 3 already deals with run state transitions. But in case I'm
missing something, could you be more specific?

> 
> 2) Format of the interface for other architectures (you can choose
> a different KVM supported architecture and write an example).
> 
> 3) Clear/documented management interface for the feature.

It is documented in patch 0: Documentation/virtual/kvm/pv_event.txt.
Does it need to be improved?