Re: [SeaBIOS] [PATCH v3 1/6] pci: add two-pass pci initialization code

[Michael S. Tsirkin]

On Tue, Jul 05, 2011 at 05:27:00PM +0200, Gerd Hoffmann wrote:
> diff --git a/src/pciinit.c b/src/pciinit.c
> index bfff3db..b0a712d 100644
> --- a/src/pciinit.c
> +++ b/src/pciinit.c
> @@ -12,15 +12,83 @@
>  #include "pci_regs.h" // PCI_COMMAND
>  #include "xen.h" // usingXen
>
> -#define PCI_ROM_SLOT 6
> -#define PCI_NUM_REGIONS 7
> +#define PCI_IO_INDEX_SHIFT 2
> +#define PCI_MEM_INDEX_SHIFT 12
>
> -static void pci_bios_init_device_in_bus(int bus);
> +#define PCI_BRIDGE_IO_MIN       0x100

This seems a little low: virtio block devices need I think
64 bytes at the moment. To have 32 of these behind a bridge
we'll need to allocate 2K of io memory per bridge.
this means we can have at most 31 such bridges but that
seems a reasonable limitation to me.