Re: [PATCH] kvm: don't take vcpu mutex for obviously invalid vcpu ioctls

[Christian Borntraeger]

On 09/23/2014 08:49 AM, Gleb Natapov wrote:
> On Mon, Sep 22, 2014 at 09:29:19PM +0200, Paolo Bonzini wrote:
>> Il 22/09/2014 21:20, Christian Borntraeger ha scritto:
>>> "while using trinity to fuzz KVM, we noticed long stalls on invalid ioctls. Lets bail out early on invalid ioctls". or similar?
>>
>> Okay.  David, can you explain how you found it so that I can make up my
>> mind?
>>
>> Gleb and Marcelo, a fourth and fifth opinion? :)
>>
> I agree with Christian that simpler fix is better here.
> The overhead is minimal. If we ever notice this overhead
> we can revert the patch all together since the problem it
> fixes can only be inflicted on userspace by itself and there
> are myriads other ways userspace can hurt itself.
>

Yes. Davids explanation also makes sense as a commit message. Paolo, if you use David patch with a better description of the "why" I am fine with this patch.

Christian

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