From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1N6imC-0006OR-Px
	for qemu-devel@nongnu.org; Sat, 07 Nov 2009 05:44:12 -0500
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1N6im8-0006My-9L
	for qemu-devel@nongnu.org; Sat, 07 Nov 2009 05:44:12 -0500
Received: from [199.232.76.173] (port=47111 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1N6im8-0006Mv-2E
	for qemu-devel@nongnu.org; Sat, 07 Nov 2009 05:44:08 -0500
Received: from mail2.shareable.org ([80.68.89.115]:53609)
	by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32)
	(Exim 4.60) (envelope-from <jamie@shareable.org>) id 1N6im7-0006BZ-Jp
	for qemu-devel@nongnu.org; Sat, 07 Nov 2009 05:44:07 -0500
Date: Sat, 7 Nov 2009 10:44:02 +0000
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: [Qemu-devel] [PATCH 0/4] net-bridge: rootless bridge support for
	qemu
Message-ID: <20091107104402.GA10410@shareable.org>
References: <1257294485-27015-1-git-send-email-aliguori@us.ibm.com>
	<20091105163702.GC21630@shareable.org>
	<4AF30129.7080203@us.ibm.com> <200911051820.48878.arnd@arndb.de>
	<4AF3154F.8090901@redhat.com> <4AF36DE9.3040803@us.ibm.com>
	<4AF3CF8C.1030408@redhat.com> <4AF44A33.6010602@us.ibm.com>
	<4AF53D8C.7080708@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4AF53D8C.7080708@redhat.com>
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Avi Kivity <avi@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, Arnd Bergmann <arndbergmann@googlemail.com>, agl@linux.vnet.ibm.com, Arnd Bergmann <arnd@arndb.de>, Juan Quintela <quintela@redhat.com>, Dustin Kirkland <kirkland@canonical.com>, qemu-devel@nongnu.org, Michael Tsirkin <mst@redhat.com>

Avi Kivity wrote:
> So vfork() is required, or in light of its man page and glowing 
> recommendations from the security people,

vfork() on Linux is fine to use, as long as you respect it's unwritten
requirements :-)

In a multithreaded program: you can start by spawning a thread for the
sole purpose of spawning a process.  Call vfork() from the new thread.
Then a slow exec() call won't delay the rest of the program, because
it's only blocking the thread you created.

> we can mark guest memory as 
> shared on fork and use plain fork(), like we do for pre mmu notifier 
> kernels.

Aiee - what's the plan?  Can a running KVM be forked, as in into two
separate processes to run the forked guests in parallel, or not?

Thanks,
-- Jamie