Re: [Xen-devel] Xen 4.3 development update

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

On Mon, Jun 10, 2013 at 5:04 PM, George Dunlap
<George.Dunlap@xxxxxxxxxxxxx> wrote:
> * qemu-upstream MMIO hole issue
>  > http://lists.xen.org/archives/html/xen-devel/2013-03/msg00559.html
>  > "You can reproduce it when a VM has a big pci hole size (such as
>    512MB), e.g. create a VM with a virtual device which has a 512MB
>    pci BAR."
>  priority: high
>  status: Original fix broken; investigating proper fix
>  priority: blocker (?)

Any chance someone could spend a bit of time digging into SeaBIOS /
qemu to see if:
1. SeaBIOS has any logic for querying the PCI space and changing the
size of the PCI hole
2. If SeaBIOS can do this when running on qemu, and if so, why it's not working?

This document seems to make it clear that on real hardware the BIOS is
expected to resize the PCI hole based on the available devices; for
example, "Installing PCI expansion cards may also increase the size of
the hole. The impact will depend on the amount of Memory Mapped I/O
(MMIO) space the PCI card(s) require."

http://techfiles.de/dmelanchthon/files/memory_hole.pdf

If SeaBIOS runs on real hardware, it should be able to do the same thing.

 -George

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