Re: [Xen-devel] [PATCH v17 14/23] x86/VPMU: Initialize VPMUs with __initcall

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 03.02.15 at 17:02, <boris.ostrovsky@xxxxxxxxxx> wrote:
> On 01/30/2015 09:54 AM, Jan Beulich wrote:
>>>>> On 05.01.15 at 22:44, <boris.ostrovsky@xxxxxxxxxx> wrote:
>>> +static int __init vpmu_init(void)
>>> +{
>>> +    int vendor = current_cpu_data.x86_vendor;
>>> +
>>> +    if ( vpmu_mode == XENPMU_MODE_OFF )
>>> +    {
>>> +        printk(XENLOG_INFO "VPMU: disabled\n");
>>> +        return 0;
>>> +    }
>>> +
>>> +    switch ( vendor )
>>> +    {
>>> +    case X86_VENDOR_AMD:
>>> +        if ( amd_vpmu_init() )
>>> +           vpmu_mode = XENPMU_MODE_OFF;
>>> +        break;
>>> +    case X86_VENDOR_INTEL:
>>> +        if ( core2_vpmu_init() )
>>> +           vpmu_mode = XENPMU_MODE_OFF;
>>> +        break;
>>> +    default:
>>> +        printk(XENLOG_WARNING "VPMU: Unknown CPU vendor: %d\n", vendor);
>>> +        vpmu_mode = XENPMU_MODE_OFF;
>>> +        break;
>>
>> return 0;
>>
>> (i.e. avoid printing another message below)
>>
>>> +    }
>>> +
>>> +    if ( vpmu_mode == XENPMU_MODE_OFF )
>>> +        printk(XENLOG_WARNING "VPMU: Disabling due to initialization 
>>> error\n");
>>
>> We repeatedly find that not printing at least a vague indication of
>> what went wrong makes problem analysis quite a bit more difficult.
>> It won't cost much to include the actual error code here.
> 
> 
> The actual error is printed by the architectural code (i.e. 
> amd_vpmu_init()/core2_vpmu_init()).

Then don't print another message here.

Jan


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