[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root
From: |
Kevin O'Connor |
Subject: |
Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses. |
Date: |
Sun, 14 Jun 2015 09:47:33 -0400 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Sun, Jun 14, 2015 at 02:10:22PM +0200, Michael S. Tsirkin wrote:
> On Thu, Jun 11, 2015 at 12:48:22PM -0400, Kevin O'Connor wrote:
> > The SeaBIOS code is used on both virtual machines and real machines.
> > The bus number is something that is generated by software and it is
> > not assured to be stable between boots. (For example, if someone adds
> > a PCI device to their machine between boots then every bus number in
> > the system might be different on the next boot.) The open firmware
> > paths go to great length to avoid arbitrary bus numbers today - for
> > example:
> >
> > /address@hidden/address@hidden/address@hidden,2/address@hidden/address@hidden/address@hidden/address@hidden,0
> >
> > Given the complexity to avoid arbitrary bus numbers I'm confused why
> > one would want to add them.
>
> Could you give an example real-hardware path when there are multiple
> roots though?
> I'd like to make sure what qemu generates matches that.
I don't have the hardware, but I've asked a user that does to send in
a log.
Here's a real world example of a search path that is generated today
for bus 0:
01.249: Searching bootorder for:
/address@hidden/address@hidden/address@hidden/address@hidden
Here's what SeaBIOS is coded to produce for a similar device on the
first extra pci root bus instead:
01.249: Searching bootorder for:
/address@hidden/address@hidden/address@hidden/address@hidden/address@hidden
Placing "address@hidden" after "address@hidden" is admittedly hokey, and I
don't have any issue with changing it.
-Kevin
Re: [Qemu-devel] [PATCH V2] pci: fixes to allow booting from extra root pci buses., Laszlo Ersek, 2015/06/11