Re: [RFC PATCH 0/7] Beginning implementing the AMD IOMMU emulation

Joerg Roedel
2010-03-30T19:40:57Z

Hello Eduard,

On Tue, Mar 30, 2010 at 11:20:01AM +0300, Eduard - Gabriel Munteanu wrote:
> This patchset is intended to provide a start for implementing the
> emulation of the AMD IOMMU. For those who aren't aware yet, I intend
> to participate as a student in GSoC 2010.

Great. This is a good start.

> In short, this demonstrates a mechanism of inserting ACPI tables without
> modifying SeaBIOS or other BIOS implementations. I also have a SeaBIOS
> equivalent, but I think this approach is better, at least at the moment.

I like the approach implemented in this patchset because of its
simplicity. The right place for building acpi tables is the bios,
though. I am fine with both ways. Anthony, Avi, what do you
think about it?

> I wouldn't merge this patchset yet, at least stuff after the first patch,
> until it accumulates more work. I also didn't test loading ACPI tables from
> the command line after these modifications.

When Linux finds an IVRS table it expects that there is a working AMD
IOMMU so you should change this patchset so that the ACPI table is
enabled later when the hardware emulation is working. That will keep
this work bisectable.
As the next step I suggest you to implement an AMD IOMMU pci device
with the config space, capability and the mmio register space.

Regards,

Joerg