[Qemu-devel] Re: qemu compiling error on ppc64: kvm.c:81: error: 'struct kvm_sregs' has no member named 'pvr'

[Dushyant Bansal <cs5070214@cse.iitd.ac.in>]

On Tuesday 15 February 2011 08:03 PM, Alexander Graf wrote:
> On 15.02.2011, at 15:21, Dushyant Bansal wrote:
>
>    
>>      
>>>>> Hrm. This means that your kernel headers in /usr/include/linux are too old. Can you try and find out which kernel version they are from please
>>>>>
>>>>>
>>>>>            
>>>> Yes, kernel headers version is 2.6.32. For the time being, I copied some of the header files from kvm/arch/powerpc/include/asm/ to kernel headers and qemu build was successful.
>>>> Thanks a lot.
>>>>
>>>>          
>>> Awesome! I'm eager to hear how well it works for you :)
>>>        
>> I collected some performance stats using kvm_stat. To get more information about exit counts of individual instructions, I configured CFLAGS_emulate.o with DDEBUG flag.
>> Now, I can see output of  "pr_debug("Emulating opcode %d / %d\n", get_op(inst), get_xop(inst));" instruction in kernel logs.
>> I have two queries:
>>
>> 1. The count of "Emulating opcode...." statement in /var/log/kern.log (3 million) is coming out to be much less than emulated_inst_exits (22 million) using kvm_stat.
>>      
> The kernel log ring buffer is probably faster filled than read :).
>
>    
>> 2. How to configure makefiles to get output of printk statements inside kvm/arch/powerpc/kvm/trace.h
>>      
> Better don't make them printks - just use the tracing framework. I'd write up a small howto here myself, but I'm pretty much on the jump to my plane for vacation. Avi, could you please guide him a bit on how to get data out of tracepoints?
>    
Thanks for the quick reply :)
I have added some more trace parameters in the tracing framework and 
currently, it is working fine.
1. Add new field in "struct kvm_vcpu_stat" (kvm_host.h)
2. Add corresponding entry in "struct kvm_stats_debugfs_item 
debugfs_entries[]" (book3s.c)
3. Increment or Decrement that field where ever necessary.

I can see stats for the new parameter in kvm_stat output. I guess, this 
approach is okay.

> This means exactly what it means. There are two possible causes:
>
> 1) Your kernel is too old and doesn't support the capability
> 2) Qemu was compiled with kernel headers that don't know the capability yet
>
> If it's 2, just copy some of the kvm*.h files from your kernel source over to /usr/include/linux or /usr/include/asm-powerpc and fix them up to compile (remove __user).
>
>    
I think, its reason 2. I'll try this.


Thanks,
Dushyant