From owner-freebsd-hackers@FreeBSD.ORG  Sun Mar 16 09:42:24 2008
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 1A25B10656C4
	for <freebsd-hackers@freebsd.org>; Sun, 16 Mar 2008 09:42:24 +0000 (UTC)
	(envelope-from jgordeev@dir.bg)
Received: from dir.bg (mail.dir.bg [194.145.63.28])
	by mx1.freebsd.org (Postfix) with ESMTP id B80FA8FC26
	for <freebsd-hackers@freebsd.org>; Sun, 16 Mar 2008 09:42:22 +0000 (UTC)
	(envelope-from jgordeev@dir.bg)
Received: from [78.90.113.14] (account jgordeev@dir.bg [78.90.113.14] verified)
	by srv.dir.bg (CommuniGate Pro SMTP 5.2.0)
	with ESMTPSA id 29143336; Sun, 16 Mar 2008 11:42:21 +0200
Message-ID: <47DCEBA1.8040503@dir.bg>
Date: Sun, 16 Mar 2008 11:42:57 +0200
From: Jordan Gordeev <jgordeev@dir.bg>
User-Agent: Mozilla/5.0 (X11; U; SunOS i86pc; en-US; rv:1.7) Gecko/20070606
X-Accept-Language: bg, en
MIME-Version: 1.0
To: "Andrey V. Elsukov" <bu7cher@yandex.ru>
References: <47DBC800.8030601@dir.bg> 9060000000184602561
	<160451205650165@webmail50.yandex.ru>
In-Reply-To: <160451205650165@webmail50.yandex.ru>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Cc: freebsd-hackers@freebsd.org
Subject: Re: vkernel & GSoC, some questions
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 16 Mar 2008 09:42:24 -0000

Andrey V. Elsukov wrote:

>16.03.08, 09:30, "David O'Brien" <obrien@freebsd.org>:
>  
>
>>>   Add virtual kernel (vkernel) support to FreeBSD for the i386 and amd64 
>>>architectures.
>>>
>>>The vkernel support in question is the one found in DragonFlyBSD.
>>>      
>>>
>>Not being up on DragonFlyBSD, can you better describe what "vkernel" is?
>>    
>>
>
>vkernel is similar to User Mode Linux technology. You can boot vkernel as a
>user mode process. I think it will be good to have similar in FreeBSD.
>There are several links:
>http://leaf.dragonflybsd.org/mailarchive/users/2007-01/msg00237.html
>http://www.dragonflybsd.org/docs/articles/vkernel/vkernel.shtml
>
>  
>
The two links that Andrey posted are very good. I just want to add a 
short summary:
A vkernel is a kernel running as a user process under a real kernel. The 
vkernel runs in the CPU's priviledge ring 3. It services its child 
processes like a normal kernel, but whenever a page table needs to be 
modified, context switched, or some other privileged operation needs to 
be executed, the vkernel asks the real kernel through a syscall interface.