Re: Regression in kernel 3.5 as Dom0 regarding PCI Passthrough?!

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, Aug 06, 2012 at 12:16:33PM -0400, Konrad Rzeszutek Wilk wrote:
> On Wed, Jul 25, 2012 at 09:43:57AM -0400, Konrad Rzeszutek Wilk wrote:
> > On Wed, Jul 25, 2012 at 02:30:00PM +0200, Tobias Geiger wrote:
> > > Hi!
> > > 
> > > i notice a serious regression with 3.5 as Dom0 kernel (3.4 was rock
> > > stable):
> > > 
> > > 1st: only the GPU PCI Passthrough works, the PCI USB Controller is
> > > not recognized within the DomU (HVM Win7 64)
> > > Dom0 cmdline is:
> > > ro root=LABEL=dom0root xen-pciback.hide=(08:00.0)(08:00.1)(00:1d.0)(00:1d.1)(00:1d.2)(00:1d.7)
> > > security=apparmor noirqdebug nouveau.msi=1
> > > 
> > > Only 8:00.0 and 8:00.1 get passed through without problems, all the
> > > USB Controller IDs are not correctly passed through and get a
> > > exclamation mark within the win7 device manager ("could not be
> > > started").
> > 
> > Ok, but they do get passed in though? As in, QEMU sees them.
> > If you boot a Live Ubuntu/Fedora CD within the guest with the PCI
> > passed in devices do you see them? Meaning lspci shows them?
> > 
> > 
> > Is the lspci -vvv output in dom0 different from 3.4 vs 3.5?
> > 
> > > 
> > > 
> > > 2nd: After DomU shutdown , Dom0 panics (100% reproducable) - sorry
> > > that i have no full stacktrace, all i have is a "screenshot" which i
> > > uploaded here:
> > > http://imageshack.us/photo/my-images/52/img20120724235921.jpg/
> > 
> > Ugh, that looks like somebody removed a large chunk of a pagetable.
> > 
> > Hmm. Are you using dom0_mem=max parameter? If not, can you try
> > that and also disable ballooning in the xm/xl config file pls?
> > 
> > > 
> > > 
> > > With 3.4 both issues were not there - everything worked perfectly.
> > > Tell me which debugging info you need, i may be able to re-install
> > > my netconsole to get the full stacktrace (but i had not much luck
> > > with netconsole regarding kernel panics - rarely this info gets sent
> > > before the "panic"...)
> 
> So I am able to reproduce this with a Windows 7 with an ATI 4870 and
> an Intel 82574L NIC. The video card still works, but the NIC stopped
> working. Same version of hypervisor/toolstack/etc, only change is the
> kernel (v3.4.6->v3.5).
> 
> Time to get my hands greasy with this..

And its due to a patch I added in v3.4 (cd9db80e5257682a7f7ab245a2459648b3c8d268)
- which did not work properly in v3.4, but with v3.5 got it working
(977f857ca566a1e68045fcbb7cfc9c4acb077cf0) which causes v3.5 to now work
anymore.

Anyhow, for right now jsut revert cd9db80e5257682a7f7ab245a2459648b3c8d268
and it should work for you.
> 
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