Re: PCI Passthrough, error: The driver 'pci-stub' is occupying your device 0000:08:06.2

From: Chris Wright <chrisw@sous-sol.org>
To: James Neave <roboj1m@gmail.com>
Cc: Chris Wright <chrisw@sous-sol.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	kvm@vger.kernel.org, "Roedel, Joerg" <Joerg.Roedel@amd.com>
Subject: Re: PCI Passthrough, error: The driver 'pci-stub' is occupying your device 0000:08:06.2
Date: Thu, 24 Feb 2011 16:13:32 -0800	[thread overview]
Message-ID: <20110225001332.GC4988@sequoia.sous-sol.org> (raw)
In-Reply-To: <AANLkTinhganuKabA3T2Yo52HkKaYdX5XJMF0bdxNgFxY@mail.gmail.com>

* James Neave (roboj1m@gmail.com) wrote:
> Just out of interest, what kind of mileage would I expect out of
> buying a shiny new PCIe tuner?

Hard to say.  One advantage would be if it's using MSI or MSI-X
interrupts.

> Can I pass through PCIe?

Often, yes (still some caveats w.r.t. extended config space I believe).

> Would it work better because it wouldn't be
> behind a bridge? WOULD it not be behind a bridge?

You should have a PCIe slot that does not sit behind a PCI-PCI bridge.

> As much as I'd hate to solve a problem with the application of money... :(

If you just want _one_ tuner to go to the guest, you should be able to
do that by unbinding the other devices and giving the guest just the one
usb controller (assuming just assigning the usb device itself is hitting
usb/qemu stack limitations).  The trick is to be sure to unbind any host
devices that are sharing interrupts with the one device you want the
guest to have.  With USB controllers you just have to be sure you know
which ports they map to so you don't kill a keyboard, mouse, external
disk, etc...

> (OT question, on mailing lists should I use Reply All or just reply
> and change the To address to kvm.vger.kernel.org?)

Reply all is best.

thanks,
-chris