Re: [PATCH 7/9] register mmio slots

[Glauber Costa <glommer@redhat.com>]

On Tue, Sep 23, 2008 at 10:31:30AM +0300, Avi Kivity wrote:
> Glauber Costa wrote:
>> On Sat, Sep 20, 2008 at 11:38:22AM -0700, Avi Kivity wrote:
>>   
>>> Glauber Costa wrote:
>>>     
>>>> By analysing phys_offset, we know whether a region is an mmio region
>>>> or not. If it is, register it as so. We don't reuse the same slot
>>>> infrastructure already existant, because there is a relationship between
>>>> the slot number for kvm the kernel module, and the index in the slots vector
>>>> for libkvm. However, we can do best in the future and use only a single data structure
>>>> for both.
>>>>
>>>>         
>>> Why is kvm interested in emulated mmio regions, at all?
>>>     
>> We don't need to. If the region is an mmio region, we do nothing (well, later on, I'm
>> coalescing the accesses). 
>
> Oh no you don't.
>
>> But still, we need to keep track. Otherwise, qemu can (and it will)
>> try to register subsets of that memory, but without any indication that this is part of an mmio region
>>   
>
> Why do we care?
>
>> Our algorithm will fail in this case, since we will then register a memory area we should have left blank.
>> So think of mmio in this case as a "please leave it blank".
>>   
>
> Confused.  If qemu knows about the mmio regions, surely it won't try to  
> overlay them with RAM?

Oh, you're right. I thought a lot of cases of subregions being registered lacked the proper MMIO flags.
But I think I was confused by an earlier issue. It'll get even simpler!

>
> -- 
> error compiling committee.c: too many arguments to function
>