Re: [Qemu-devel] [PATCH V7 0/2] Add option to configure guest vPMU

[Wei Huang]

On 10/25/2016 10:59 AM, Peter Maydell wrote:
> On 25 October 2016 at 16:26, Peter Maydell <address@hidden> wrote:
>> On 25 October 2016 at 08:33, Andrew Jones <address@hidden> wrote:
>>> Yes, I prefer it to not being able to easily switch a command line from
>>> KVM to TCG. Granted, right now we mostly need to run with -cpu host for
>>> KVM, which also needs to be switched for TCG. However that will hopefully
>>> change with Shannon's work.
>>
>> If the TCG default is different from the KVM default then you
>> will have problems with switching it anyway, because it will
>> silently change behaviour underfoot. I think we should avoid that...
> 
> So here's my suggestion: we should just not worry about printing
> a warning for not actually honouring the "please give me a PMU"
> flag under TCG. At some point we'll actually implement it,
> at which point the problem goes away. In the meantime (a) not
> providing a PMU and not bothering to say so is what we were
> doing before, and (b) there's lots of bits of the CPU that we
> don't actually yet implement in TCG but which will appear as
> we fix bugs in the emulation.

This is easy to implement. If Drew is OK with silence under TCG mode, I
will send V8 out.

> 
> thanks
> -- PMM
>