Re: [Xen-devel] [PATCH 4 of 4] Linux pvops: xen pci platformdevice driver

From: Ian Campbell
Date: Thu Mar 04 2010 - 10:32:41 EST


On Wed, 2010-03-03 at 17:14 +0100, Bastian Blank wrote:
>
> > During the initialization of the xen pci device driver, we write to
> a
> > magic ioport that causes qemu to unplug some emulated devices, disc
> and
> > network in particular.
> > This parameter is meant to present the user a choice about what
> emulated
> > devices to unplug.
>
> Somehow I don't think this belongs here. It looks like a workaround,
> you can always ask qemu to not bind them at the beginning and the
> guest system to not provide drivers.

Qemu needs to start off providing the devices so that the BIOS and
bootloader can do their thing. It's only once the final OS is up and
running that we want to swap to the paravirt drivers and this interface
provides a safe mechanism to ensure only one set of devices is active at
a time.

Ian.

--
Ian Campbell
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