Re: Booting/installing WindowsNT

[Avi Kivity <avi@redhat.com>]

On 05/05/2010 01:18 PM, Andre Przywara wrote:
> Michael Tokarev wrote:
>> 05.05.2010 12:32, Andre Przywara wrote:
>>> Avi Kivity wrote:
>>>> On 05/04/2010 06:27 PM, Andre Przywara wrote:
>>>>>
>>>>>> 3. In all other cases so far it BSoDs with STOP 0x3E error
>>>>>> right before displaying that kernel message.
>>>>> MSDN talks about a mulitprocessor configuration error:
>>>>> http://msdn.microsoft.com/en-us/library/ms819006.aspx
>>>>> I suspected the offline CPUs in the mptable that confuse NT. But -smp
>>>>> 1,maxcpus=1 does not make a difference. I will try to dig deeper in
>>>>> this area.
>>> OK, I tackled this down. It is the max CPUID level that differs.
>>> In the AMD CPUID guide leafs 0000_0002 till 0000_0004 are reserved, the
>>> CPU that Michael and I used (K8RevF) actually have a max leaf of 1 
>>> here.
>>> Default qemu64 has a max leaf of 4.
>>> So by saying -cpu qemu64,level=1 (or 2 or 3) it works for me.
>>> Modern OS only read leaf 4 on Intel systems, it seems that NT4 is
>>> missing this.
>>
>> Confirmed, with -cpu qemu64,level=[123] it works for me as well.
> The strange thing is that NT4 never reads leaf 4:
> kvm-2341  [003]   228.527874: kvm_cpuid: func 40000000 rax 0 rbx 
> 4b4d564b rcx 564b4d56 rdx 4d
> kvm-2341  [003]   228.530033: kvm_cpuid: func 1 rax 623 rbx 800 rcx 
> 80002001 rdx 78bfbfd
> kvm-2341  [003]   228.530081: kvm_cpuid: func 80000000 rax 8000000a 
> rbx 68747541 rcx 444d4163 rdx 69746e65
> kvm-2341  [003]   228.530084: kvm_cpuid: func 80000008 rax 3028 rbx 0 
> rcx 0 rdx 0
> kvm-2341  [003]   228.530147: kvm_cpuid: func 1 rax 623 rbx 800 rcx 
> 80002001 rdx 78bfbfd
> kvm-2341  [002]   228.538254: kvm_cpuid: func 1 rax 623 rbx 800 rcx 
> 80002001 rdx 78bfbfd
> kvm-2341  [002]   228.539902: kvm_cpuid: func 1 rax 623 rbx 800 rcx 
> 80002001 rdx 78bfbfd
> kvm-2341  [002]   236.273370: kvm_cpuid: func 1 rax 623 rbx 800 rcx 
> 80002001 rdx 78bfbfd
> kvm-2341  [002]   236.273381: kvm_cpuid: func 0 rax 4 rbx 68747541 rcx 
> 444d4163 rdx 69746e65

So maybe it's just a simple guest bug that was never encountered in real 
life because no processors had that leaf.

>
> With level=4 it BSODs afterwards, with level=1 it beyond that:
> kvm-2472  [002]   871.379192: kvm_cpuid: func 1 rax 623 rbx 800 rcx 
> 80002001 rdx 78bfbfd
> kvm-2472  [002]   871.379235: kvm_cpuid: func 0 rax 1 rbx 68747541 rcx 
> 444d4163 rdx 69746e65
> kvm-2472  [002]   871.379238: kvm_cpuid: func 1 rax 623 rbx 800 rcx 
> 80002001 rdx 78bfbfd
> ....
>
> Interestingly it also accesses leaf 8000_0008, I thought that that 
> leaf wasn't around in 1996.

It's the bios:
src/mtrr.c:            cpuid(0x80000008u, &eax, &ebx, &ecx, &edx);


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