Re: [PATCH v6 11/19] x86/VPMU: Initialize PMU for PV guests

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

On 05/20/2014 11:51 AM, Jan Beulich wrote:
>>>> On 13.05.14 at 17:53, <boris.ostrovsky@oracle.com> wrote:
>> --- a/xen/arch/x86/hvm/svm/svm.c
>> +++ b/xen/arch/x86/hvm/svm/svm.c
>> @@ -1150,7 +1150,8 @@ static int svm_vcpu_initialise(struct vcpu *v)
>>           return rc;
>>       }
>>   
>> -    vpmu_initialise(v);
>> +    if ( is_hvm_domain(v->domain) )
>> +        vpmu_initialise(v);
> Why?

This patch adds initialization for PV domains, which is conditioned by 
is_pv_domain() in amd_vpmu_initialise()/core2_vpmu_alloc_resource(). I 
don't want PVH domains (which call these routines) to try to set up 
their VPMUs from here. This is supposed to happen via pvpmu_init() 
(which in this patch will return -EINVAL for PVH).

Same reason for conditioning vpmu_destroy().

I think I should drop this whole business of delaying PVH support until 
later patch and do it incrementally at the same time as I add PV 
support. (The reason, BTW, for doing it this way was because when I 
started with this project PVH support wasn't there yet and I couldn't 
test it).


-boris