[Qemu-devel] SVM support in 0.12?

[Qemu-devel] SVM support in 0.12?

[Jun Koi]

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??

Thanks,
Jun

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

[Jun Koi]

On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi <junkoi2004@gmail.com> 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)

Thanks,
J

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

[Alexander Graf]

Am 18.12.2009 um 03:39 schrieb Jun Koi <junkoi2004@gmail.com>

> On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi <junkoi2004@gmail.com>  
> 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.

If you use -cpu qemu32 that also means you'll get an emulated Intel  
CPU. KVM-AMD will refuse there.

Also, back when I developed it, 32-bit kvm didn't really work  
properly. So please let me know what you find out!

Alex
>

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

[Paolo Bonzini]

On 12/18/2009 03:39 AM, Jun Koi wrote:
> On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi<junkoi2004@gmail.com>  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.

SVM requires a 64-bit machine (so you can run 32-bit Linux but you need 
to use qemu-system-x86_64).

Paolo

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

[Jun Koi]

On Fri, Dec 18, 2009 at 8:35 PM, Alexander Graf <agraf@suse.de> wrote:
>
> Am 18.12.2009 um 03:39 schrieb Jun Koi <junkoi2004@gmail.com>
>
>> On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi <junkoi2004@gmail.com> 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.
>
> If you use -cpu qemu32 that also means you'll get an emulated Intel CPU.
> KVM-AMD will refuse there.
>
> Also, back when I developed it, 32-bit kvm didn't really work properly. So
> please let me know what you find out!

I tried the latest Qemu code, with the following command:

qemu -m 500 -cpu qemu32,+svm -cdrom ubuntu.iso

I verified that /proc/cpuinfo has no svm flag. So SVM doesnt work on 32bit host.

I will try that with 64bit host to see how it goes.

Thanks,
Jun

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

[Alexander Graf]

Am 18.12.2009 um 17:52 schrieb Jun Koi <junkoi2004@gmail.com>:

> On Fri, Dec 18, 2009 at 8:35 PM, Alexander Graf <agraf@suse.de> wrote:
>>
>> Am 18.12.2009 um 03:39 schrieb Jun Koi <junkoi2004@gmail.com>
>>
>>> On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi <junkoi2004@gmail.com>  
>>> 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.
>>
>> If you use -cpu qemu32 that also means you'll get an emulated Intel  
>> CPU.
>> KVM-AMD will refuse there.
>>
>> Also, back when I developed it, 32-bit kvm didn't really work  
>> properly. So
>> please let me know what you find out!
>
> I tried the latest Qemu code, with the following command:
>
> qemu -m 500 -cpu qemu32,+svm -cdrom ubuntu.iso
>
> I verified that /proc/cpuinfo has no svm flag. So SVM doesnt work on  
> 32bit host.
>
> I will try that with 64bit host to see how it goes.

The host doesn't matter. You can easily run qemu-system-x86_64 on a 32- 
bit host.

Alex

>
> Thanks,
> Jun

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

[Jamie Lokier]

Alexander Graf wrote:
> 
> Am 18.12.2009 um 03:39 schrieb Jun Koi <junkoi2004@gmail.com>
> 
> >On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi <junkoi2004@gmail.com>  
> >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?

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

> 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.

-- Jamie

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 <junkoi2004@gmail.com>
>>
>>     
>>> On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi <junkoi2004@gmail.com>  
>>> 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

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

[Jun Koi]

On Sat, Dec 19, 2009 at 2:34 AM, Alexander Graf <agraf@suse.de> wrote:
>
> Am 18.12.2009 um 17:52 schrieb Jun Koi <junkoi2004@gmail.com>:
>
>> On Fri, Dec 18, 2009 at 8:35 PM, Alexander Graf <agraf@suse.de> wrote:
>>>
>>> Am 18.12.2009 um 03:39 schrieb Jun Koi <junkoi2004@gmail.com>
>>>
>>>> On Fri, Dec 18, 2009 at 11:37 AM, Jun Koi <junkoi2004@gmail.com> 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.
>>>
>>> If you use -cpu qemu32 that also means you'll get an emulated Intel CPU.
>>> KVM-AMD will refuse there.
>>>
>>> Also, back when I developed it, 32-bit kvm didn't really work properly.
>>> So
>>> please let me know what you find out!
>>
>> I tried the latest Qemu code, with the following command:
>>
>> qemu -m 500 -cpu qemu32,+svm -cdrom ubuntu.iso
>>
>> I verified that /proc/cpuinfo has no svm flag. So SVM doesnt work on 32bit
>> host.
>>
>> I will try that with 64bit host to see how it goes.
>
> The host doesn't matter. You can easily run qemu-system-x86_64 on a 32-bit
> host.
>

I can confirm that SVM works well on x86-64 target, but fails on i386 target.

Thanks,
J

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

[Andre Przywara]

Jun Koi wrote:
>>>>>> 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.
>>>>
...
>>> qemu -m 500 -cpu qemu32,+svm -cdrom ubuntu.iso
>>>
>>> I verified that /proc/cpuinfo has no svm flag. So SVM doesnt work on 32bit
>>> host.
>>>
>>> I will try that with 64bit host to see how it goes.
>> The host doesn't matter. You can easily run qemu-system-x86_64 on a 32-bit
>> host.
>>
> 
> I can confirm that SVM works well on x86-64 target, but fails on i386 target.

The Linux kernel will only detect SVM if the machine is AMD (see 
linux-2.6/arch/x86/include/asm/virtext.h:cpu_has_svm())
So please try:
$ qemu -m 500 -cpu qemu32,+svm,vendor=AuthenticAMD -cdrom ubuntu.iso
(because the default vendor for qemu32 is Intel, for qemu64 AMD)

Regards,
Andre.

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448 3567 12
----to satisfy European Law for business letters:
Advanced Micro Devices GmbH
Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen
Geschaeftsfuehrer: Andrew Bowd; Thomas M. McCoy; Giuliano Meroni
Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen
Registergericht Muenchen, HRB Nr. 43632

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

[Andre Przywara]

Andre Przywara wrote:
> Jun Koi wrote:
>>>>>>> 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.
>>>>>
> ...
>>>> qemu -m 500 -cpu qemu32,+svm -cdrom ubuntu.iso
>>>>
>>>> I verified that /proc/cpuinfo has no svm flag. So SVM doesnt work on 
>>>> 32bit
>>>> host.
>>>>
>>>> I will try that with 64bit host to see how it goes.
>>> The host doesn't matter. You can easily run qemu-system-x86_64 on a 
>>> 32-bit
>>> host.
>>>
>>
>> I can confirm that SVM works well on x86-64 target, but fails on i386 
>> target.
> 
> The Linux kernel will only detect SVM if the machine is AMD (see 
> linux-2.6/arch/x86/include/asm/virtext.h:cpu_has_svm())
> So please try:
> $ qemu -m 500 -cpu qemu32,+svm,vendor=AuthenticAMD -cdrom ubuntu.iso
> (because the default vendor for qemu32 is Intel, for qemu64 AMD)

Should have checked this before the post ;-):
qemu32 has a xlevel of 0, so no AMD-defined CPUID leafs will be parsed.
Either fix this explicitly with xlevel=0xa or use athlon as your base 
CPU model:
$ qemu -m 500 -cpu athlon,+svm -cdrom ubuntu.iso

This made my Linux show the SVM flag.

Regards,
Andre.

-- 
Andre Przywara
AMD-OSRC (Dresden)
Tel: x29712