Re: [PATCH v3 11/16] x86/VPMU: Add support for PMU register handling on PV guests

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

On 01/13/2014 09:12 AM, Jan Beulich wrote:
>>>> On 06.01.14 at 20:24, Boris Ostrovsky <boris.ostrovsky@oracle.com> wrote:
>> @@ -866,7 +867,6 @@ void pv_cpuid(struct cpu_user_regs *regs)
>>           break;
>>   
>>       case 0x00000005: /* MONITOR/MWAIT */
>> -    case 0x0000000a: /* Architectural Performance Monitor Features */
>>       case 0x0000000b: /* Extended Topology Enumeration */
>>       case 0x8000000a: /* SVM revision and features */
>>       case 0x8000001b: /* Instruction Based Sampling */
>> @@ -875,7 +875,9 @@ void pv_cpuid(struct cpu_user_regs *regs)
>>       unsupported:
>>           a = b = c = d = 0;
>>           break;
>> -
>> +    case 0x0000000a: /* Architectural Performance Monitor Features (Intel) */
>> +        vpmu_do_cpuid(0xa, &a, &b, &c, &d);
>> +        break;
>>       default:
> Rather than removing a blank line here, you ought to insert a
> second one so that there's one before _and_ after the added
> code block.
>
> Furthermore the need to pass 0xa as the first argument suggests
> that you're not in line with the intentions of vpmu_do_cpuid():
> Either you drop the first parameter from the function, or you get
> your code in line with the existing caller.

Not sure I understand the problem. We fill a, b, c and d with HW values 
for dom0 and then call vpmu_do_cpuid() to adjust them if needed. And 
whether or not this is needed is based on the first argument.

(There is a bug in this routine in that it looks like I am not calling 
vpmu_do_cpuid() for non-dom0 PV guest but that's a different issue).

-boris