Re: [PATCH 3/9] change order of kvm_init call.

[Anthony Liguori <aliguori@us.ibm.com>]

Glauber Costa wrote:
> On Sun, Jul 26, 2009 at 08:59:44PM +0200, Jan Kiszka wrote:
>   
>> Glauber Costa wrote:
>>     
>>> The goal is to get rid of the call to kvm_init. But those things
>>> are subtle, and often break. So do it in a separate patch, to help
>>> finding potential issues in future bisections.
>>>       
>> Found such an issued: This patch triggers a segfault if no kvm modules
>> are loaded and you start qemu without -no-kvm. Please have a look.
>>
>> Jan
>>     
>
> ok, the culprit seems to be a 
>
>     if (kvm_enabled())
>         return;
>
> in the beginning of code_gen_alloc.
>
> It is 7f3d0cbe, by Avi, and according to changelog, suggested by anthony.
> I however, fail to realise the purpose of this optimization. For one thing,
> it totally dictates that kvm has absolutely to be enabled or disabled prior
> to this point. No mind changing later. Also, the real deal is to be able
> to compile out tcg entirely. The strategy of just disabling the code gen
> alloc is a minor nitpick that just papers over this.
>   

I agree with you in principle but I think reverting this papers over an 
issue.

Why are we touching code_gen_ptr when using KVM?  Can someone post the 
full back trace?

-- 
Regards,

Anthony Liguori