vkernel & GSoC, some questions

[Jordan Gordeev]

Andrey V. Elsukov wrote:

>16.03.08, 09:30, "David O'Brien" <obrien at 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.