Re: [PATCH v7 06/13] KVM: x86: Add Intel Processor Trace virtualization mode

[Paolo Bonzini]

On 03/05/2018 13:32, Alexander Shishkin wrote:
>>  
>> +/* Default is SYSTEM mode. */
>> +static int __read_mostly pt_mode = PT_MODE_SYSTEM;
>> +module_param(pt_mode, int, S_IRUGO);
> So, it's an explicit module parameter? One apparent problem with this
> is that one would need to reload kvm module(s) to be able to use PT,
> which is not ideal.

If you want to do tracing system-wide, that by definition must disable
guest tracing, so I think the module parameter is appropriate.  The
question is more, what is the best default.

Paolo