Re: [RFC PATCH] kvm: Enable -cpu option to hide KVM

Bandan Das
2014-06-02T19:03:08Z

Michael Tokarev <mjt@tls.msk.ru> writes:

> 02.06.2014 17:30, Alex Williamson wrote:
>> On Mon, 2014-06-02 at 14:32 +0400, Michael Tokarev wrote:
>>> 01.06.2014 20:25, Alex Williamson wrote:
>>>> The latest Nvidia driver (337.88) specifically checks for KVM as the
>>>> hypervisor and reports Code 43 for the driver in a Windows guest when
>>>> found. Removing or changing the KVM signature is sufficient to allow
>>>> the driver to load.
>>>
>>> Hmm.. Why does it do such thing? Is it in order to prevent the driver
>>> to work in a virtualized windows, ie to prevent vga passthough to work?
>>>
>>> If that's the case, I think it is a lost game. Because they'll be adding
>>> more, cleverer, checks in the next version.
>>
>> Then they'll be pissing off more users and driving them to AMD by doing
>> so. In any case, having the ability to hide the hypervisor seems to
>> stand on it's own. What if we want to test whether a guest behavior is
>> the result of a paravirtual interface? What if a user wants to hide the
>> hypervisor in order to further reduce the exposure surface to the VM?
>> There are reasons beyond an arms race with Nvidia to want a feature like
>> this. Thanks,
>
> You answer as if I were strongly against the change. I'm not.
> What I'm against is about the reasoning. This way you're just
> accepting the arm race.

Couldn't the arms race be a little less explicit if the commit message
is changed :) ? Why mention Nvidia at all ? Just state that the intended
application is for cases where the user might still want to run a piece
of software that bails out when KVM is detected.

> Thanks,
>
> /mjt
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