Re: [Xen-users] [solved] Error: pci: 0000:01:07.0: non-page-aligned MMIO BAR found.

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Sat, Mar 13, 2010 at 12:29:43PM +0100, Christian Kniep wrote:
> Hi Folks,
> 
> I make I new approach to pimp up my xen-Kernel in higher version-numbers.
> Currently I run a selfcompiled 2.6.27-Kernel from:
> hg clone http://xenbits.xensource.com/ext/linux-2.6.27-xen.hg
> 

Just a note to everyone, the ext/linux-2.6.27-xen.hg tree shouldn't be used!! 
It's known to be buggy and unmaintained!!

See: http://wiki.xensource.com/xenwiki/XenDom0Kernels


> In the next step I want to run the kernel from jemery:
> git clone git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git
> 
> I tried the last couple of days to get pci-passtrough work with jeremys 
> kernel but I still get:
> ----
> chieftec:~# xm create vdr1.cfg
> Using config file "/etc/xen/vdr1.cfg".
> Error: pci: 0000:01:07.0: non-page-aligned MMIO BAR found.
> ----
> 

Hmm.. I haven't seen that earlier. What kind of device are you trying to 
passthrough?


> For quite a long I zero in on the following lines in "xm dmesg":
> -------
> (XEN) AMD SVM: ASIDs enabled.
> (XEN) HVM: SVM enabled
> (XEN) HVM: Hardware Assisted Paging detected.
> [..]
> (XEN) AMD-Vi: IOMMU not found! <------ (kernel option iommu=1)
> (XEN) I/O virtualisation disabled <----- 
>

Does your hardware actually have an IOMMU that can be used for HVM guest PCI 
passthrough? 


> -------
> After a while I found out that this errors also could be find in the working 
> 2.6.27-kernel. So I guess that could not be what caused this mess. :)
> 
> While I write this mail I found the solution??? *DANCING*
> So for all who are struggling with this akward error:
> -> xen-pciback.hide=(X:XX.X) pci=resource_alignment=XX:XX.X <-
> works for me!

Good to hear!

> ----
> title           Xen 3.4.2 / 2.6.31.12-xen4
> root            (hd0,6)
> kernel          /boot/xen-3.4.2.gz 
> module          /boot/vmlinuz-2.6.31.12-xen4 root=/dev/sda7 ro console=tty0 
> pci=nomsi noreboot xen-pciback.hide=(01:07.0) pci=resource_alignment=01:07.0
> module          /boot/initrd.img-2.6.31.12-xen4
> ----
> 
> Now I get:
> -----
> chieftec:~# xm create vdr1.cfg
> Using config file "/etc/xen/vdr1.cfg".
> Started domain vdr1 (id=1)
> chieftec:~# 
> -----
> 

I assume 'vdr1' guest is PV. 
PV guests don't require IOMMU for PCI passthrough. 

Xen HVM guests require hardware IOMMU for PCI passthru.

-- Pasi


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