Re: [Qemu-devel] nested page table translation for non-x86 operating system

[陳韋任]

> 1.  The control of gCR3 and hCR3 needs kernel access. While they can
> be set with a device module as what is done in kvm. Trapping into the
> kernel every time gCR3 is reseted might be too expensive.

  Why the control of gCR3 needs kernel access? Isn't gCR3 just a field of the
CPUX86State? QEMU should have the control of it. Or you mean the trapping thing?
 
> 2. After setting the gCR3 and hCR3. whatever memory references fall
> within the guest memory will be done correctly. However, memory
> references done by the host will be broken. Therefore, when we load
> the from the CPUstates, call to helpers for exits from the code cache,
> we need to change the paging mechanism back to non-nested. can this be
> done ? how expensive will this be ?

  Why the memeory references done by the host will be broken?

Regards,
chenwj
 
-- 
Wei-Ren Chen (陳韋任)
Computer Systems Lab, Institute of Information Science,
Academia Sinica, Taiwan (R.O.C.)
Tel:886-2-2788-3799 #1667
Homepage: http://people.cs.nctu.edu.tw/~chenwj