>I need to see a pretty strong justification for why we should be adding
new kinds of devices to the virt machine,
The designware i2c controller is a very common controller on many ARM
SoCs.  It has device tree bindings and ACPI bindings which makes it ideal
for this platform.

>Forgot to mention, but my prefered approach for providing
>an i2c controller on the virt board would be to have a
>PCI i2c controller: that way users who do need it can plug it
>in with a -device command line option, and users who don't
>need it never have to worry about it.
The device is enabled by a machine parameter, “-machine virt,smbus=true”,
and is disabled by default.

> (We seem to have an ICH9-SMB PCI device already; I have no idea if it's
suitable.)
I didn't find that device suitable because it is part of the Intel
Southbridge, which may have some Intel platform quirks, and we don't need
all the things in that IO hub.

-Chris