Re: Problem with PCI Pass-through address space collision

Gordan Bobic
2013-05-23T06:53:06Z

On 05/21/2013 04:33 PM, Jon Skilling wrote:
> Hi Gordan,
>
> Thanks for your reply.  It is my understanding that PCI pass-through should
> work for PV guests, which is what I am creating here.  One thing that I
> notice though, other than XL DMESG giving the message about Vt-d being
> disabled, is that other than the command line message, iommu=soft
doesn''t
> seem to produce any confirmation messages anywhere so I can''t
really tell if
> this is running or not.
>
> I have to confess that I have not seen any documentation on XL stating that
> the device must be detached from Dom0 before it can be attached to a guest.
> Certainly, XL pci-detach freePBX 06:01.0 produces an error saying that the
> domain is invalid.  However, I tried your suggestion prior to starting the
> domain and it runs without complaint and says that the device has been
> detached.
>
> I reincorporated your suggestion into xen-pciback.conf and added modprobe
> xen-pciback into rc.local to get everything to start at boot up and
> restarted the machine.
> I then ran the virsh-nodev-detach command followed by xl create -c
> freePBX.cfg.  Unfortunately, this produced the same result as before.
>
> I''ve also tried adding iommu=soft to the Dom0 kernel line, but as
I said,
> this didn''t produce any discernible differences to the XL DMESG
output.
>
> Instead of hotplugging, I tried adding the two last lines to the end of the
> freePBX.cfg file:
>
> name = "freePBX"
> uuid = "91cd5696-1451-c333-f6a4-1628a79976bd"
> maxmem = 1024
> memory = 1024
> vcpus = 1
> bootloader = "pygrub"
> localtime = 0
> on_poweroff = "destroy"
> on_reboot = "restart"
> on_crash = "restart"
> disk = [ "phy:/dev/VolGroup/freePBX,xvda,w" ]
> vif = [
"mac=00:16:3e:00:9a:9c,bridge=br0,script=vif-bridge,vifname=vif2.0"
> ]
>
> extra = "iommu=soft debug loglevel=10 earlyprintk=xenboot console=hvc0
ro
> xencons=tty"
> pci = [''06:01.0,permissive=1'']
>
> As you can see from above, I''m allocating 1024Mb to the guest.  I
haven''t
> got time now until the weekend to apply the 4.2.2-5 patches to check if
they
> solve my problem, but I''ll post a message when I''ve done
it to update on how
> it went.  Suffice to say, I''m still getting the same error message
:-(

Have you tried using xm instead of xl? I''m finding that xl is still
missing some vital features to make everything work.

I''d also start with getting a standard HVM domU working with xm and
then
take it further from there.

I''m pretty sure iommu=soft shouldn''t be on the domU kernel
boot
parameters. I suggest you start by removing the extra= line and remove
the ,permissive=1 from the pci spec since I don''t think xm understands
that (you have it in your module config anyway). Then see if you can get
it working with xm/xend as a HVM.

Gordan