[Lguest] Lguest Improvement

[Rusty Russell]

On Mon, 6 Dec 2010 08:42:46 pm eviatar wrote:
> Hi Rusty,
> 
> As I see it there are two possibilities:
> 1) The straight forward way but maybe not modular: Duplicate all of this
> manually (BTW how pagetables could be reconstructed?)
> 2) More adventurer way: start a new guest (after fork() and LHREQ_SAVE)
> using LHREQ_INIT with the added functionality to receive all the
> registers, not only eip.

(2) Rename LHREQ_INIT to LHREQ_START or something, and have it take all the
registers.

BTW, please take care to make sure the work is done in small pieces!  I use
guilt on top of git to manage patch sets like this, so I can jump back and
forth and add new patches.

I am thinking of changing how pagetables work; the kernel has changed
again, and in Linus' latest kernel lguest is broken.  The new approach would
mean starting in a special "linear" mode (no page tables) until the guest
loads cr3.  This would be simpler, I think, than the current startup code
which creates a temporary pagetable at the top of memory and hopes the kernel
won't overwrite it...

Cheers,
Rusty.
PS.  CC'd the mailing list, as I'm sure others are interested in this work!