Re: [Xen-devel] [PATCH 3/6] x86/vpmu: Remove core2_no_vpmu_ops

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 11/16/2016 12:04 PM, Andrew Cooper wrote:
> On 16/11/16 16:27, Boris Ostrovsky wrote:
>> On 11/16/2016 07:31 AM, Andrew Cooper wrote:
>>> diff --git a/xen/arch/x86/cpu/vpmu.c b/xen/arch/x86/cpu/vpmu.c
>>> index a542f4d..1f822ca 100644
>>> --- a/xen/arch/x86/cpu/vpmu.c
>>> +++ b/xen/arch/x86/cpu/vpmu.c
>>> @@ -136,9 +136,10 @@ int vpmu_do_msr(unsigned int msr, uint64_t 
>>> *msr_content,
>>>      const struct arch_vpmu_ops *ops;
>>>      int ret = 0;
>>>  
>>> +    /* Don't leak PMU MSRs to unprivileged domains. */
>> This was a somewhat incorrect comment originally and since you are
>> moving it then perhaps it's worth adding something along the lines of
>> "if VPMU is off or if the privileged domain is profiling whole system".
>> Otherwise it gives impression that unprivileged domains never access
>> those MSRs.
> /*
>  * Hide the PMU MSRs if vpmu is not configured, or the hardware domain
>  * is profiling the whole system.
>  */
>
> ?


Sure, thanks.

(or, in fact, you can just drop the whole comment since I think it's
pretty obvious what's going on).

-boris

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