Re: [Qemu-devel] Prohibit Windows from running in QEMU

[Peter Lieven]

Am 04.08.2017 um 12:43 schrieb Paolo Bonzini:
> On 04/08/2017 12:27, Peter Lieven wrote:
>> Am 04.08.2017 um 12:23 schrieb Paolo Bonzini:
>>> On 04/08/2017 11:58, Peter Lieven wrote:
>>>> Am 29.10.2013 um 10:59 schrieb Paolo Bonzini:
>>>>> Il 29/10/2013 10:48, Peter Lieven ha scritto:
>>>>>> Hi all,
>>>>>>
>>>>>> this question might seem a bit weird, but does anyone see a good way to
>>>>>> avoid
>>>>>> that Windows is able to boot inside qemu?
>>>>>>
>>>>>> We have defined several profiles for different operation systems and I 
>>>>>> want
>>>>>> to avoid that someone chooses Linux and then installs Windows within
>>>>>> a VM. Reason is licensing.
>>>>> Patch QEMU to crash when Hyper-V extensions are enabled...
>>>> Hi all,
>>>>
>>>> this is an old topic that has become important for me again recently.
>>>> Now all Linux versions should be able to detect KVM even if Hyper-V is 
>>>> enabled.
>>>>
>>>> But how do I detect from Qemu userspace that Hyper-V is enabled?
>>> Maybe a better one: make KVM crash the guest if CR8 is nonzero on a
>>> vmexit.  Linux doesn't use it, Windows should not survive long.
>> You mean the kvm kernel module? Or can I access this register also
>> from Qemu on any call that is handled in userspace? It would be easier
>> to have a cmdline option to Qemu than an option to a kernel module.
> Yes, the kernel module.  Accessing it in QEMU requires
> cpu_synchronize_state so it's slow.  However, you could piggyback on
> some other functionality that is never used by Linux to do the check,
> for example the RTC I/O port.
>
> That is, in the RTC I/O port code you call cpu_synchronize_state and
> check CR8.

Thanks, I will try that out and let you know.

Peter