Re: [Qemu-ppc] [Qemu-devel] emulate powerpc(mpc8544ds) on x86 architecture

[Alexander Graf]

On 20.02.2013, at 19:30, Scott Wood wrote:

> On 02/20/2013 08:46:52 AM, Alexander Graf wrote:
>> On 20.02.2013, at 15:07, Andreas Färber wrote:
>> > Hi,
>> >
>> > Am 20.02.2013 10:22, schrieb Shi Rong:
>> >> I want to emulate powerpc(mpc8544ds) on x86 architecture, is anybody
>> >> succeed in it?
>> >
>> > If you CC Power Architecture questions to qemu-ppc, you have higher
>> > chances of getting replies from the experts.
>> >
>> >> My working step:
>> >> about qemu:
>> >> ./configure --cpu=ppc --target-list=ppc-softmmu --enable-fdt
>> >> --enable-kvm --enable-tcg-interpreter --enable-linux-user
>> >> --prefix=/home/shir/install/qemu/
>> >> make
>> >> make install
>> >
>> > --cpu=ppc is bogus, just drop it.
>> > Also --enable-tcg-interpreter is unnecessary on x86.
>> Also no need for enable-kvm, as you're running on x86. KVM only helps for 
>> compatible CPUs (ppc on ppc for example).
>> >
>> >> but everytime I start my qemu-system-ppc,
>> >> qemu-system-ppc -M mpc8544ds -kernel uImage -append "root=/dev/ram
>> >> rdinit=/linuxrc" -initrd initrd -nographic
>> >> I get this error :
>> >> "KVM: Couldn't find level irq capability. Expect the VM to stall at times
>> >> kvm_init_vcpu failed: Cannot allocate memory"
>> >
>> > What kernel are you using? Sounds like it is lacking some required feature.
>> This is probably because you compiled with -cpu=ppc. Without, KVM shouldn't 
>> get detected and all is well.
> 
> Still, why is it trying to use KVM without the user explicitly asking for it 
> (at runtime, not in the build)?  What if I want to emulate an mpc8544 on a 
> powermac?

Because we don't have a way to match compatibility yet :). KVM can't tell you 
"yes, I can virtualize this CPU flavor". Or rather: It doesn't. When setting 
PVR we could fail and declare the target CPU as unsupported.


Alex