Re: Setting nx bit in virtual CPU

[Andre Przywara <andre.przywara@amd.com>]

Richard Simpson wrote:
> On 08/04/10 09:52, Andre Przywara wrote:
> 
>> Can you try to boot the attached multiboot "kernel", which just outputs
>> a brief CPUID dump?
>> $ qemu-kvm -kernel cpuid_mb -vnc :0
>> (Unfortunately I have no serial console support in there yet, so you
>> either have to write the values down or screenshot it).
>> In the 4th line from the button it should print NX (after SYSCALL).
> 
> OK, that was fun!  Resulting screen shots are attached.
> 
> ...default.png		With command line above.
> ...cpu_host.png		With -cpu host option added.
> ...no_kvm.png		With -no-kvm option added.
> 
> I hope that helps!

OK, AFAIK there are several flags missing. I dimly remember there was a 
bug with masking the CPUID bits in older kernels, so I guess you have to 
celebrate your uptime for the last time and then give it a reboot with a 
more up-to-date host kernel.
(I also rebooted my desktop after I made the one year and now am gone 
green with turning it off over night ;-)
Maybe you get around with rebuilding fixed versions of kvm.ko and 
kvm_amd.ko, I can provide a fix for you if you wish (please point me to 
a way to get the actual kernel source you use).
The userspace was up-to-date? (qemu-kvm 0.12.3)?

Regards,
Andre.

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 488-3567-12