Re: [Qemu-devel] [PATCH v3 3/4] pc & q35: Add new object pc-memory-layout.

[Paolo Bonzini]

Il 24/03/2014 19:55, Don Slutz ha scritto:
> This new object has the property max-ram-below-4g.
>
> If you add enough PCI devices then all mmio for them will not fit
> below 4G which may not be the layout the user wanted. This allows
> you to increase the below 4G address space that PCI devices can use
> (aka decrease ram below 4G) and therefore in more cases not have any
> mmio that is above 4G.
>
> For example adding "-global pc-memory-layout.max-ram-below-4g=2G" to
> the command line will limit the amount of ram that is below 4G to
> 2G.

Does Xen's firmware allow 64-bit BARs?  I'm wondering why this is not a 
problem on KVM.

Also, overloading -global like this isn't the best long term choice.  We 
should get custom -machine properties in 2.1, we should use them.

Paolo