[SeaBIOS] [PATCH] pci: improve io address space allocation
kraxel at redhat.com
Mon Feb 3 08:06:42 CET 2014
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.
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