Re: [PATCH v11 for-xen-4.5 15/20] x86/VPMU: Add support for PMU register handling on PV guests

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

On 09/23/2014 11:08 AM, Konrad Rzeszutek Wilk wrote:
>>   static void core2_vpmu_load(struct vcpu *v)
>> @@ -447,7 +461,6 @@ static int core2_vpmu_msr_common_check(u32 msr_index, int *type, int *index)
>>   static int core2_vpmu_do_wrmsr(unsigned int msr, uint64_t msr_content,
>>                                  uint64_t supported)
>>   {
>> -    u64 global_ctrl;
>>       int i, tmp;
>>       int type = -1, index = -1;
>>       struct vcpu *v = current;
>> @@ -492,6 +505,7 @@ static int core2_vpmu_do_wrmsr(unsigned int msr, uint64_t msr_content,
>>       {
>>       case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
>>           core2_vpmu_cxt->global_status &= ~msr_content;
>> +        wrmsrl(MSR_CORE_PERF_GLOBAL_OVF_CTRL, msr_content);
> The original code does the write in core2_vpmu_do_interrupt with a bunch of filtering.
> Is there a particular reason we don't want to do that?

No good reason. We definitely should check whether the value we are 
writing is valid.

(And masking in core2_vpmu_do_interrupt is slightly incorrect so I'll 
fix it as well)



-boris