From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Baptiste Favre Subject: Re: PCI passthrough issue Date: Wed, 12 Jan 2011 17:56:45 +0100 Message-ID: <4D2DDD4D.9090503@jbfavre.org> References: <4D2DCB09.5010703@jbfavre.org> <20110112154344.GA28780@dumpdata.com> <4D2DCE8F.3060504@jbfavre.org> <20110112163647.GB10863@dumpdata.com> Reply-To: xen-devel@lists.xensource.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20110112163647.GB10863@dumpdata.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Le 12/01/2011 17:36, Konrad Rzeszutek Wilk a =E9crit : > 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 =E9crit : >>> 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 domai= n >>>> 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 drive= r >>> to see if it is just a routing issue? >> Have not tried to eliminate xen network driver. Think I have both driv= ers. >> >> My kernel .config looks like: >> $ grep XEN build_dir/linux-x86_xen_domu/linux-2.6.37/.config >> CONFIG_XEN=3Dy >> # CONFIG_XEN_PRIVILEGED_GUEST is not set >> CONFIG_XEN_PVHVM=3Dy >> CONFIG_XEN_MAX_DOMAIN_MEMORY=3D128 >> CONFIG_XEN_SAVE_RESTORE=3Dy >> CONFIG_PCI_XEN=3Dy >> CONFIG_XEN_PCIDEV_FRONTEND=3Dy >> CONFIG_XEN_BLKDEV_FRONTEND=3Dy >> CONFIG_XEN_NETDEV_FRONTEND=3Dy >> CONFIG_HVC_XEN=3Dy >> CONFIG_XEN_BALLOON=3Dy >> CONFIG_XEN_SCRUB_PAGES=3Dy >> CONFIG_XEN_DEV_EVTCHN=3Dy >> CONFIG_XENFS=3Dy >> CONFIG_XEN_COMPAT_XENFS=3Dy >> CONFIG_XEN_SYS_HYPERVISOR=3Dy >> # CONFIG_XEN_PLATFORM_PCI is not set >> CONFIG_SWIOTLB_XEN=3Dy >> >> So, I should remove CONFIG_XEN_NETDEV_FRONTEND ? >=20 > No. You can just do 'ifconfig 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 Us= e >> 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 >=20 > Ok, then the idea that the Xen networking driver and the PCI passthroug= h send > packets over is not the way.. >=20 > So ignore about the Xen networking part. OK. >> >>>> - Starting domU as a "normal" (ie without PCI passthrough), no probl= em. >>>> >>>> >>>> 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 leng= th. >>> >>> Then that would imply the MTU is not set right.=20 >> Already checked it: 1500 :) > Ok. >=20 > 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 m= achine > (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= . > What happens if the PCI passthrough device is not under the ownership o= f 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 Regards, JB