Re: [PATCH] kvm-userspace: set pci mem to start at 0xc100000 and vesa to 0xc000000

[Izik Eidus <ieidus@redhat.com>]

Chris Wright wrote:
> * Izik Eidus (ieidus@redhat.com) wrote:
>   
>> This patch make the pci mem region larger (1 giga now).
>> this is needed for pci devices that require large amount of memory
>> such as video cards.
>>
>> for pea guests this patch is not an issue beacuse the guest OS will map
>> the rest of the ram after 0x100000000...,
>> for 32bits that arent pea, it mean the maximum memory that would be
>> avaible now is 3giga.
>>     
>
> Seems a little heavy handed.
>
> a) Given the size...code could be cleaned up so that a simple constant
> change doesn't need to touch so much code.
>   

Yea it probably can...

> b) It is brute force.  I'm not sure it really matters all that much to
> limit a 32-bit (non-PAE) guest to 3G, but it's a little extreme for the
> cases that don't care about the large hole. 
>
> Is there anyway to make it dynamic based on the requirements of the
> devices that are part of the launched VM?
>   

There is (you need to transfer data to the bios but it is possible...), 
the thing is - there was concern that
it will make windows crazy if you keep changing the devices physical mapping

Avi what do you think?

> thanks,
> -chris
>