Re: [Qemu-devel] How to measure guest memory access (qemu_ld/qemu_st) time?

[Wei-Ren Chen]

>   The reason why we want to do the measuring is we want to use KVM (sounds 
> crazy
> idea) MMU virtualization to speedup the guest -> host memory address 
> translation.
> I talked to some people on LinuxCon Japan, included Paolo, about this idea. 
> The
> feedback I got is we can only use shadow page table rather than EPT/NPT to do
> the address translation (if possible!) since different ISA (ARM and x86, for
> example) have different page table format. Besides, QEMU has to use ioctl to 
> ask
> KVM to get the translation result, but it's an overkill as the ARM page table
> is quite simple, which can be done in user mode very fast.

  Anyone would like to give a comment on this? ;)

  From the talk with Laurent on #qemu, he said the way he thought of is
translating GVA -> GPA manually (through software), then try to insert
GPA -> HPA into EPT, that's the only way HW can help.

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