On Fr, 2014-01-31 at 23:20 -0800, H. Peter Anvin wrote:
On 01/23/2014 07:03 AM, Gerd Hoffmann wrote:
This patch improves the io address space allocation. It adds a check that the region above 0xc000 which is traditionally used for pci io is actually big enougth. If it isn't it tries the larger window at 0x1000. If that is to small too it errors out.
When creating guests with multiple pci-pci bridges (and devices with io regions behind them) the 0xc000 -> 0xffff region quickly becomes too small.
While being at it document the io address space layout used by qemu/seabios.
Silly question: why not just allocate from the top down?
qemu uses ports in the 0xa000 -> 0xbfff region, that why seabios traditionally starts allocating from 0xc000 upwards.