VIA Nano support

VIA Nano support

[Rusty Burchfield]

When trying to boot installer iso's on this platform I get the
following error about 40 times per second in my kern.log.
kernel: [ 4857.828875] handle_exception: unexpected, vectoring info
0x8000080e intr info 0x80000b0d

These options have no effect: -no-kvm-irqchip or -no-kvm-pit
QEMU is working fine.

Interestingly, specifying the -uuid option causes it to freeze
immediately.  Without that option it gets to the iso's boot screen and
freezes after attempting to continue past there.

Is this an expected condition for this platform / is this a platform
anyone is interested in supporting? ;-)

Thanks,
Rusty


Platform information:
$ cat /proc/cpuinfo
processor	: 0
vendor_id	: CentaurHauls
cpu family	: 6
model		: 15
model name	: VIA Nano processor U2250 (1.6GHz Capable)
stepping	: 3
cpu MHz		: 1599.796
cache size	: 1024 KB
fpu		: yes
fpu_exception	: yes
cpuid level	: 10
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov
pat clflush acpi mmx fxsr sse sse2 ss tm pbe syscall nx lm
constant_tsc up rep_good pni monitor vmx est tm2 ssse3 cx16 xtpr rng
rng_en ace ace_en ace2 phe phe_en lahf_lm
bogomips	: 3199.59
clflush size	: 64
cache_alignment	: 128
address sizes	: 36 bits physical, 48 bits virtual
power management:
$ uname -a
Linux gicodefs 2.6.32-21-generic #32-Ubuntu SMP Fri Apr 16 08:09:38
UTC 2010 x86_64 GNU/Linux
$ kvm -version
QEMU PC emulator version 0.12.3 (qemu-kvm-0.12.3), Copyright (c)
2003-2008 Fabrice Bellard
$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=10.04
DISTRIB_CODENAME=lucid
DISTRIB_DESCRIPTION="Ubuntu 10.04 LTS"

Re: VIA Nano support

[Avi Kivity]

On 04/26/2010 04:14 AM, Rusty Burchfield wrote:
> When trying to boot installer iso's on this platform I get the
> following error about 40 times per second in my kern.log.
> kernel: [ 4857.828875] handle_exception: unexpected, vectoring info
> 0x8000080e intr info 0x80000b0d
>
> These options have no effect: -no-kvm-irqchip or -no-kvm-pit
> QEMU is working fine.
>
> Interestingly, specifying the -uuid option causes it to freeze
> immediately.  Without that option it gets to the iso's boot screen and
> freezes after attempting to continue past there.
>
> Is this an expected condition for this platform / is this a platform
> anyone is interested in supporting? ;-)
>    

It's a known bug in the Nano's vmx implementation.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

Re: VIA Nano support

[Yuhong Bao]

> It's a known bug in the Nano's vmx implementation.
Any details or workarounds?

Yuhong Bao

Re: VIA Nano support

[Avi Kivity]

On 05/02/2010 01:40 AM, Yuhong Bao wrote:
>> It's a known bug in the Nano's vmx implementation.
>>      
> Any details or workarounds?
>    

There's a bug in the vm86/vmx interaction that happens to hit kvm.  No 
known workarounds.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.

RE: VIA Nano support

[Yuhong Bao]

>> Any details or workarounds?
>>
>
> There's a bug in the vm86/vmx interaction that happens to hit kvm. No
> known workarounds.

What about details?
Yuhong Bao 		 	   		  
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Re: VIA Nano support

[Harald Welte]

On Sun, May 02, 2010 at 01:21:46AM -0700, Yuhong Bao wrote:

> >> Any details or workarounds?
> >>
> >
> > There's a bug in the vm86/vmx interaction that happens to hit kvm. No
> > known workarounds.
> 
> What about details?
> Yuhong Bao 		 	   		  

Sorry,

I'm not subscribed to the KVM list, and I personally don't know too
much about the virtualization support in modern x86 CPUs.

If there's a specific technical question, I'm happy to forward it to the
engineers at VIA and try to get a response for you.

In this case, please send your question as detailed/specific as possible,
thanks!

Regards,
	Harald
-- 
- Harald Welte <HaraldWelte@viatech.com>	    http://linux.via.com.tw/
============================================================================
VIA Free and Open Source Software Liaison

Re: VIA Nano support

[Harald Welte]

JFYI,

Jesse Ahrens (who is with the CPU design unit of VIA, Centaur Technology) has
written the following statement to the KVM list more than a year ago:

http://marc.info/?l=kvm&m=123861829901077

So if your question/issue is regarding stepping < 3, then it is something
VIA explicitly indicates is not supported and has not been finished.

"has not been finished" sounds much more like "really is not complete at all"
than "just a minor bug that wasn't caught before taping out".

Regards,
	Harald
-- 
- Harald Welte <HaraldWelte@viatech.com>	    http://linux.via.com.tw/
============================================================================
VIA Free and Open Source Software Liaison

RE: VIA Nano support

[Yuhong Bao]

> So if your question/issue is regarding stepping < 3, then it is something
> VIA explicitly indicates is not supported and has not been finished.
It is about stepping 3, see the original post for the cpuinfo.
 		 	   		  
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Re: VIA Nano support

[Rusty Burchfield]

On Sun, May 2, 2010 at 1:21 AM, Yuhong Bao <yuhongbao_386@hotmail.com> wrote:
> What about details?

This old thread seems to have more details.
http://www.mail-archive.com/kvm@vger.kernel.org/msg11704.html

Hopefully they are of more use to you than me ;-)

Thanks,
Rusty

Re: VIA Nano support

[Rusty Burchfield]

On Mon, May 3, 2010 at 9:42 AM, Rusty Burchfield
<gicodewarrior@gmail.com> wrote:
> On Sun, May 2, 2010 at 1:21 AM, Yuhong Bao <yuhongbao_386@hotmail.com> wrote:
>> What about details?
>
> This old thread seems to have more details.
> http://www.mail-archive.com/kvm@vger.kernel.org/msg11704.html

Any new information out there?

~Rusty