Re: [libvirt] [PATCH] qemu: use "ide" as device name for implicit SATA controller on Q35
On Fri, Sep 20, 2013 at 04:35:12PM +0200, Gerd Hoffmann wrote:
Hi,
> 1) Every SATA controller has 6 buses, and each bus allows a single
> target (or "unit").
That is how it is modeled in qemu, largely due to reusing the ide code.
On real hardware you have a sata controller with a number of ports
(happens to be 6 for the one emulated by qemu, but that may be different
on other controllers). You can plug a single device into each port.
There is not really a concept of a sata bus.
Ok, so in libvirt terminology then, using 'unit' to map to the 'port'
is what we want to be doing, and ignore the 'bus' attribute for sata
drives.
> (or are we just stuck with the current state of unit being
interpreted
> as bus for sata addresses? :-/)
I'd say continuing using 'unit' is fine. When changing the way the
address is specified in xml I'd rather go for something like this:
<address type=sata controller=0 port=2 />
We already use type=drive for addressing sata drives (and indeed any
other drives attached to disk controllers), so we won't be inventing
a new address type.
Daniel
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