Re: [Qemu-devel] Re: SVM support in 0.12?

[Alexander Graf]

Jamie Lokier wrote:
> Alexander Graf wrote:
>   
>> Am 18.12.2009 um 03:39 schrieb Jun Koi <address@hidden>
>>
>>     
>>> On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi <address@hidden>  
>>> wrote:
>>>       
>>>> Hi,
>>>>
>>>> I am running latest Qemu 0.12-rc. My guest VM runs Linux kernel  
>>>> 2.6.31.
>>>>
>>>> Because Qemu now supports SVM, I expect to see the SVM flag in
>>>> /proc/cpuinfo, but that is not the case.
>>>>
>>>> So it seems SVM support is not enabled by default configuration??
>>>>
>>>>         
>>> My host and guest are both 32 bit Linux, if that matters.
>>>
>>> (And this is pure Qemu, without using KVM or KQemu)
>>>       
>> Kqemu actually works with svm emulation.
>>
>> Have you tried -cpu qemu32,+svm? I think I only enabled svm on qemu64,  
>> because I'm not aware of 32-bit AMD CPUs that can do svm.
>>     
>
> 32-bit VT (Intel) definitely exists.
>
> If there aren't any 32-bit AMDs with SVM, does SVM even have defined
> 32-bit semantics?
>   

Yes, it does.

> But I see the kvm kernel code can build 32-bit SVM support.  I wonder
> if it has ever been tested :-)
>   

Well, just because all SVM capable CPUs are long mode capable doesn't
mean you have to run an x86_64 kernel on them.

>> Also, back when I developed it, 32-bit kvm didn't really work  
>> properly. So please let me know what you find out!
>>     
>
> Do you mean 32-bit kvm on a 32-bit host, or 32-bit kvm inside your SVM
> emulation?  kvm works very well on 32-bit Intel hosts.
>   

32-bit kvm inside my SVM emulation.


Alex