[Qemu-devel] Re: [PATCH] QEMU - provide e820 reserve through qemu_cfg

[Alexander Graf]

On 25.01.2010, at 22:05, Jes Sorensen wrote:

> On 01/25/10 21:14, Anthony Liguori wrote:
>> On 01/25/2010 02:04 PM, Alexander Graf wrote:
>>> Yes, sounds good. Should be fairly extensible then. What about memory
>>> holes? Do we need to take care of them?
>> 
>> It would be nice for QEMU to be able to add additional e820 regions that
>> don't necessarily fit the standard layout model.
>> 
>> For instance, I've thought a number of times about using a large
>> reserved region as a shared memory mechanism.
>> 
>> But we certainly need to allow the BIOS to define the regions it needs
>> to know about.
> 
> I think it should be easy to accommodate using the scheme I am
> suggesting. It would require some basic testing for conflicts in the
> BIOS, but otherwise it should pretty much allow you to specify any
> region you want as a reserved block.
> 
> Only problem is that we don't really have a way to pass back info
> saying 'you messed up trying to pinch an area that the BIOS wants
> for itself'.

Eh - the BIOS shouldn't even try to use regions that are declared as reserved 
using this interface.
I guess we're mostly talking about DMI and ACPI tables. They can be anywhere in 
RAM.

Alex