Re: [Qemu-devel] [Xen-devel] [BUG 1747]Guest could't find bootable device with memory more than 3600M

[Paolo Bonzini]

Il 13/06/2013 09:54, George Dunlap ha scritto:
> 
> Also, as I understand it, at the moment:
> 1. Some operating systems (32-bit XP) won't be able to use relocated
> devices
> 2. Some devices (without 64-bit BARs) can't be relocated

Are there really devices with huge 32-bit BARs?  I think #1 is the only
real problem, so far though it never was for KVM.

SeaBIOS sorts the BARs from smallest to largest alignment, and then from
smallest to largest size.  Typically only the GPU will be relocated.

Paolo

> 3. qemu-traditional is fine with a resized <4GiB MMIO hole.
> 
> So if we have #1 or #2, at the moment an option for a work-around is to
> use qemu-traditional.
> 
> However, if we add your "print an error if the device doesn't fit", then
> this option will go away -- this will be a regression in functionality
> from 4.2.
> 
> I thought that what we had proposed was to have an option in xenstore,
> that libxl would set, which would instruct hvmloader whether to expand
> the MMIO hole and whether to relocate devices above 64-bit?