Re: [Qemu-devel] [RFC v5 0/6] pci_expander_brdige: support separate pci domain for pxb-pcie

[Gerd Hoffmann]

> > > 2. Only 4x devices is supported, you need to be careful not to overuse
> >
> > Could you elaborate on this please? What happens if you are not careful?
> > How does management know what the limits are?
> 
> It means the user might use more space than 768MB for mmconfig,
> which is [0x80000000m 0xb0000000). If such situation happens,  seabios
> will ignore all extra pxb-pcie devices and not adding e820 entry for them,
> which makes all the devices under them unworkable.

Ypu should clearly note that this is a limitation of the seabios support
patches then, so not an issue of the qemu patches.

> As for the management, will some checks when adding mcfg be enough for
> management? Or I can maintain a variable to indicate how many space
> have been consumed and warn the user if they exceed the threshold?
> The latter allows us to do the check when the pxb-pcie is initializing.

I think qemu should not apply any restrictions here.

cheers,
  Gerd