Re: [RFC PATCH v3 0/3] Add segment limit checks to emulator

[Avi Kivity <avi@redhat.com>]

On 07/12/2010 01:56 AM, Mohammed Gamal wrote:
> fter some conversation with Avi concerning why unreal mode has been seen to work
> with KVM on Intel. It clears out the scenario is caused as follows:
>
> - guest enters big real mode
> - kvm squashes limit to 64k-1
> - guest executes instructions with offset>  64k
> - cpu issues #GP due to limit violation
> - kvm handle_rmode_exception() ->  emulator
> - emulator ignores limit, emulates instruction
>
> With these applied I am getting vmentry failures with SeaBIOS and
> gPXE. I could still get SeaBIOS to work with emulate_invalid_guest_state=1.
> So it's needless to say that these patches are not meant for merging!
>    

Well, eventually you need to fix this.

> --------
>
> Changes from v2:
> - Addeded generic segment limit check helpers
> - Removed individual segment register segment helpers as they're no longer needed
>
>    

What about the rest of my comments?

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.