Re: [Xen-devel] frontend and backend

[Mark Williamson <Mark.Williamson@xxxxxxxxxxxx>]

> Hi, I am reading frontend and backend block drivers. I find the frontend
> and the backend are matched magicly by xend. Is there any way for the
> frontend to choose a backend by itself? I am trying to provide a new pair
> of frontend and backend drivers. How can I let xend know they should match
> each other? I can assign them a different pair of IDs in
> domain_controller.h, of course.

If you want the frontend itself to be able to choose, you should add a domid 
field into one of the frontend's control messages, then write appropriate 
code in Xend that will parse this message and notify the correct backend.  
This is what I have done for XenFS.

> Another question is about the function virt_to_machine. Does it convert
> linear address to machine address? Is the machine address here the same as
> physical memory address? If not, when a page is used as a shared ring, why
> the machine address is sent, instead of the physical address?

Virtual addresses == what the application sees (as per normal)
(Pseudo)physical addresses == what most of the guest kernel regards as 
physical memory.  It provides the illusion of a contiguous physical memory.  
These don't have much meaning outside the domain.
Machine addresses == The actual address in the machine's memory, suitable for 
inserting into page tables and for passing to other domains so they can map 
your memory.

HTH,
Mark

> --------------------------
> Zhiyi from EPFL Switzerland
>
>
>
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
> http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.sourceforge.net/lists/listinfo/xen-devel


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel