Re: qemu-system-x86_64 locks hard when used with kvm

[Amit Shah <amit.shah-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

On Monday 15 October 2007 01:54:03 Jan Frey wrote:
> Hi,
>
> I intended to use qemu-system-x86_64 with kvm for full virtualization.
> My host is
>
> # cat /proc/cpuinfo
> processor       : 0
> vendor_id       : AuthenticAMD
> cpu family      : 15
> model           : 127
> model name      : AMD Athlon(tm) 64 Processor 3500+
> stepping        : 1
> cpu MHz         : 1000.000
> cache size      : 512 KB
> fpu             : yes
> fpu_exception   : yes
> cpuid level     : 1
> wp              : yes
> flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
> cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt rdtscp
> lm 3dnowext 3dnow rep_good pni cx16 lahf_lm svm extapic cr8_legacy
> misalignsse
> bogomips        : 2010.55
> TLB size        : 1024 4K pages
> clflush size    : 64
> cache_alignment : 64
> address sizes   : 40 bits physical, 48 bits virtual
> power management: ts fid vid ttp tm stc 100mhzsteps
>
>
> So you can see AMD's "svm" is existent.
> Host's kernel is 2.6.23.1, config file is attached.
> KVM/Qemu sources I've tried include -37, -40, -45 and -46.
>
> When I run something like
> qemu-system-x86_64 -m 384 -no-kvm <somevdisk>
>
> The virtual machine boots and everything works fine (except the
> slowliness ;-)).
> But when I try without the "-no-kvm" switch the whole host machine
> immediately freezes hard (no windows come up, no text on the console,
> mouse frozen, amazing though that machine still reacts to ping on
> network.. but anyway, even reset button at the PC doesn't help, I've got
> to switch off power..)
>
> The host distribution is FC6.

That's really strange. I use kvm (frequently updated to the latest git) daily 
and I don't face any such issues.

Can you try this:

Don't load the kvm modules (or rmmod kvm-amd; rmmod kvm if they're already 
loaded) and then try the qemu command line without --no-kvm? Does it lock up 
even then?

Also, can you try what you've tried previously on a text console (not within 
X). If there's any kernel output, it'll be dumped.

Amit.

>
> Am I doing something substantially wrong?
>
> Any help appreciated.
>
> Regards,
> Jan



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