Re: [BUG] kvm: guest can not startup due to triple fault

[Avi Kivity]

 On 10/18/2010 03:46 PM, Avi Kivity wrote:
>  On 10/18/2010 03:45 PM, Dave Young wrote:
> > On Mon, Oct 18, 2010 at 03:26:30PM +0200, Avi Kivity wrote:
> > >   On 10/18/2010 02:58 PM, Dave Young wrote:
> > > >>
> > > >>   It's secondary_startup_64 enabling efer.sce and efer.nx.
> > > >>
> > > >>   Dave, please post your /proc/cpuinfo.  Is your host running 
> > with NX
> > > >>   disabled?
> > > >
> > > >I see nx bit in /proc/cpuinfo, Actually I don't know how to 
> > disable it.
> > >
> > >  Strange.
> > >
> > >  Please patch arch/x86/kvm/x86.c to printk efer_reserved_bits (a
> > >  global), efer (an argument) and old_efer (a local), and post the
> > >  results.
> >
> > I add printk before kvm_mmu_reset_context(vcpu), correct? get 
> > following value:
>
> Add it at the beginning please, otherwise we'll miss the important one 
> due to an early return.

No need actually:

> [ 3228.468325] efer_reserved_bits = 0xfffffffffffffafe


Bit 11 is reserved, so the guest can't enable nx.

From arch/x86/kvm/vmx.c:
> static __init int hardware_setup(void)
> {
>     if (setup_vmcs_config(&vmcs_config) < 0)
>         return -EIO;
>
>     if (boot_cpu_has(X86_FEATURE_NX))
>         kvm_enable_efer_bits(EFER_NX);

Please patch hardware_setup() to show the value of 
boot_cpu_has(X86_FEATURE_NX).

--
error compiling committee.c: too many arguments to function

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