Re: swapping with MMU Notifiers V2

Carsten Otte
2008-01-30T15:14:48Z

Avi Kivity wrote:
> Carsten Otte wrote:
>> We have similar restrictions than you're naming here. Our guest may
>> start at a (userspace-) page boundary, and has a fixed 1:1 mapping to
>> userspace for a given length. We do that by just having one memory
>> slot which has to start at virtual address zero in kvm.
>
> I thought you're using an offset to put the guest somewhere else?
> Putting the guest at offset zero means that a qemu null pointer deref
> causes a memory corruption instead of an abort.
At a page boundary in userspace (non-zero), that matches zero in guest
physical. 1:1+n. Sorry for causing the confusion, my explanation was
diffuse.

>> I have way to few knowledge about x86, but to me both the native page
>> table layout and the nested one look very similar. I believe AMD has
>> done a pretty good job designing that.
>
> The page table formats are identical.
Looks like Andrea should start hacking then ;-).