On Wed, Jan 12, 2011 at 05:56:45PM +0100, Jean Baptiste Favre wrote:
> Le 12/01/2011 17:36, Konrad Rzeszutek Wilk a écrit :
> > On Wed, Jan 12, 2011 at 04:53:51PM +0100, Jean Baptiste Favre wrote:
> >> Hello Konrad,
> >> Le 12/01/2011 16:43, Konrad Rzeszutek Wilk a écrit :
> >>> On Wed, Jan 12, 2011 at 04:38:49PM +0100, Jean Baptiste Favre wrote:
> >>>> Hello,
> >>>> I'm facing a strange issue with network card PCI passthrough on my
> >>>> openwrt test domU.
> >>>> - With network PCI passthrough, DNS lookup failed for some domains
> >>>> (exemple, google.com) but not for other (free.fr my ISP, or my domain
> >>>> jbfavre.org). I can ping an IP address without any problem.
> >>> Do you have "both" (so PCI passthrough and the Xen network driver)
> >>> in the guest? If so, have you tried eliminating the xen network driver
> >>> to see if it is just a routing issue?
> >> Have not tried to eliminate xen network driver. Think I have both drivers.
> >> My kernel .config looks like:
> >> $ grep XEN build_dir/linux-x86_xen_domu/linux-2.6.37/.config
> >> CONFIG_XEN=y
> >> # CONFIG_XEN_PRIVILEGED_GUEST is not set
> >> CONFIG_XEN_PVHVM=y
> >> CONFIG_XEN_MAX_DOMAIN_MEMORY=128
> >> CONFIG_XEN_SAVE_RESTORE=y
> >> CONFIG_PCI_XEN=y
> >> CONFIG_XEN_PCIDEV_FRONTEND=y
> >> CONFIG_XEN_BLKDEV_FRONTEND=y
> >> CONFIG_XEN_NETDEV_FRONTEND=y
> >> CONFIG_HVC_XEN=y
> >> CONFIG_XEN_BALLOON=y
> >> CONFIG_XEN_SCRUB_PAGES=y
> >> CONFIG_XEN_DEV_EVTCHN=y
> >> CONFIG_XENFS=y
> >> CONFIG_XEN_COMPAT_XENFS=y
> >> CONFIG_XEN_SYS_HYPERVISOR=y
> >> # CONFIG_XEN_PLATFORM_PCI is not set
> >> CONFIG_SWIOTLB_XEN=y
> >> So, I should remove CONFIG_XEN_NETDEV_FRONTEND ?
> > No. You can just do 'ifconfig <x> down' whatever your Xen netfront
> > NIC is. .. but.
> >>> What does your routing table look like? Your IP table?
> >> My routing table is pretty clean, nothing strange here
> >> # route -n
> >> Kernel IP routing table
> >> Destination Gateway Genmask Flags Metric Ref Use
> >> Iface
> >> 10.0.0.0 0.0.0.0 255.255.255.0 U 0 0 0
> >> br-wan
> >> 0.0.0.0 10.0.0.1 0.0.0.0 UG 0 0 0
> >> br-wan
> > Ok, then the idea that the Xen networking driver and the PCI passthrough
> > send
> > packets over is not the way..
> > So ignore about the Xen networking part.
> >>>> - Starting domU as a "normal" (ie without PCI passthrough), no problem.
> >>>> As far as I can say, domU is not the root cause. I really think this is
> >>>> related to PCI passsthrough. This seems to be related to packet length.
> >>> Then that would imply the MTU is not set right.
> >> Already checked it: 1500 :)
> > Ok.
> > Next thing, did you try to disable the rx/tx checksumming?
> No. Not sure I even know how to do it, but will have a look on that.
> > If you connect the Ethernet cable for this 'br-wan' device to another
> > machine
> > (so you could set it up as bridge and just let it pass through packets and
> > sniff
> > the data) what do the packets look like?
> I can see packets on my gateway (which acts as DNS as well). They looks
> good. I can see DNS answers as well leaving the gateway, but not
> reaching my domU. Have only basic switches between my gateway and my domU.
Wait a minute. How are your domU's connected? You did turn on
forwarding in your guest with the PCI passthrough right?
How is your domain (with the PCI passthrought) connected to the
> > What happens if the PCI passthrough device is not under the ownership of a
> > bridge?
> > What then? You wouldn't have any bridge firewall code in?
> Removed bridge + configure eth: no change.
> Checked ebtables/iptables (all tables: net filter and mangle) rules:
> empty, Policy to ACCEPT.
> Tried to enable/disable ip_forwarding: no change
> Also disabled IPV6 support (I saw some DNS answers as AAAA but no IPv6
> available at home for now): no change
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