[SeaBIOS] [RFC v2 0/3] Support multiple pci domains in pci_device
Gerd Hoffmann
kraxel at redhat.com
Tue Aug 28 08:07:52 CEST 2018
Hi,
> Since we will not use all 256 buses of an extra PCI domain,
> I think this space will allow us to support more PCI domains.
Depends on the use case I guess. If you just need many pcie devices
this probably doesn't help. If you want them for numa support then yes,
more domains with less devices each can be useful then.
> How will the flow look like ?
>
> 1. QEMU passes to SeaBIOS information of how many extra
> PCI domains needs, and how many buses per domain.
> How it will pass this info? A vendor specific capability,
> some PCI registers or modifying extra-pci-roots fw_cfg file?
Where is the pxb-pcie device? 0000:$somewhere? Or $domain:00:00.0?
> 2. SeaBIOS assigns the address for each PCI Domain and
> returns the information to QEMU.
> How it will do that? Some pxb-pcie registers? Or do we model
> the MMCFG like a PCI BAR?
If we can access pxb-pcie registers before configuring MMCFG then yes,
we should use pxb-pcie registers for that.
cheers,
Gerd
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