On 06/10/17 13:14, Robin Murphy wrote: > Hi Will, > > On 06/10/17 01:19, Will Trives wrote: >> Hello, >> >> Just reporting that it looks like this patch may fix the error (so >> people having issues with VIA controller hosts may also want to try it): >> >> https://lists.linuxfoundation.org/pipermail/iommu/2017-September/024371.html >> >> It appears that my ax88179 is working just fine now with the vendor >> driver. So perhaps it's possible to revert the old commit in the linux >> kernel and allow the use of scatter gather ? (perhaps for non-intel >> hosts ? I'm not sure if this device is effected by intel xhci errata) > > Thanks for the tip-off - as luck would have it I have an AX88179 dongle > to hand! Does the out-of-tree driver behave significantly differently to > the mainline driver (CONFIG_USB_NET_AX88179_178A)? To answer myself - yes, the out-of-tree driver produces all manner of >PAGE_SIZE offsets for dma_map_sg(): ... [ 571.019335] xhci_hcd 0000:04:00.0: ####### sg->offset = 0x7770 [ 571.025497] xhci_hcd 0000:04:00.0: ####### sg->offset = 0x7a60 [ 571.031402] xhci_hcd 0000:04:00.0: ####### sg->offset = 0x1100 [ 571.037353] xhci_hcd 0000:04:00.0: ####### sg->offset = 0x1c50 [ 571.043254] xhci_hcd 0000:04:00.0: ####### sg->offset = 0x27a0 ... So my patch should indeed be the right thing to fix the combination of that driver and intel-iommu. > I stuck a PCIe USB3 card into my arm64 dev board and brought up the ASIX > dongle with 4.14-rc3 and the mainline driver - with some added debug > checks it's definitely not hitting the same sg->offset > PAGE_SIZE case > as the crypto drivers which prompted the above patch, but I *do* see an > out-of-bounds DMA access under network load which looks a lot like a > buffer overrun from the XHCI controller: > > [ 41.324904] arm-smmu 2b500000.iommu: Unhandled context fault: > fsr=0x2, iova=0xfff49000, fsynr=0x183, cb=0 > > This is fairly easy to reproduce with iperf, so I'll dig in and see how > it's related. And that turns out to be a red herring, in this context at least. In a cruel twist of fate I'd inadvertently found a card with the infamous VIA VL805 - it actually does that for any USB3 device, and crucially a different card with a Renesas chip doesn't. Robin. >> commit: e2ed511400d41e0d136089d5a55ceab57c6a2426 >> >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e2ed511400d41e0d136089d5a55ceab57c6a2426 >> >> >> ethtool -k enp2s0u1u4 >> Features for enp2s0u1u4: >> Cannot get device udp-fragmentation-offload settings: Operation not supported >> rx-checksumming: off [fixed] >> tx-checksumming: on >> tx-checksum-ipv4: on >> tx-checksum-ip-generic: off [fixed] >> tx-checksum-ipv6: on >> tx-checksum-fcoe-crc: off [fixed] >> tx-checksum-sctp: off [fixed] >> scatter-gather: on >> tx-scatter-gather: on >> tx-scatter-gather-fraglist: off [fixed] >> tcp-segmentation-offload: on >> tx-tcp-segmentation: on >> tx-tcp-ecn-segmentation: off [fixed] >> tx-tcp-mangleid-segmentation: off >> tx-tcp6-segmentation: off [fixed] >> udp-fragmentation-offload: off >> generic-segmentation-offload: on >> generic-receive-offload: on >> large-receive-offload: off [fixed] >> rx-vlan-offload: off [fixed] >> tx-vlan-offload: off [fixed] >> ntuple-filters: off [fixed] >> receive-hashing: off [fixed] >> highdma: off [fixed] >> rx-vlan-filter: off [fixed] >> vlan-challenged: off [fixed] >> tx-lockless: off [fixed] >> netns-local: off [fixed] >> tx-gso-robust: off [fixed] >> tx-fcoe-segmentation: off [fixed] >> tx-gre-segmentation: off [fixed] >> tx-gre-csum-segmentation: off [fixed] >> tx-ipxip4-segmentation: off [fixed] >> tx-ipxip6-segmentation: off [fixed] >> tx-udp_tnl-segmentation: off [fixed] >> tx-udp_tnl-csum-segmentation: off [fixed] >> tx-gso-partial: off [fixed] >> tx-sctp-segmentation: off [fixed] >> tx-esp-segmentation: off [fixed] >> fcoe-mtu: off [fixed] >> tx-nocache-copy: off >> loopback: off [fixed] >> rx-fcs: off [fixed] >> rx-all: off [fixed] >> tx-vlan-stag-hw-insert: off [fixed] >> rx-vlan-stag-hw-parse: off [fixed] >> rx-vlan-stag-filter: off [fixed] >> l2-fwd-offload: off [fixed] >> hw-tc-offload: off [fixed] >> esp-hw-offload: off [fixed] >> esp-tx-csum-hw-offload: off [fixed] >> rx-udp_tunnel-port-offload: off [fixed] >> >> >> Regards, >> >> >> Will >> >> On Fri, 29 Sep 2017 09:58:07 +1000 >> Will Trives <renevant@xxxxxxxxxxxxxxxx> wrote: >> >>> Hello, >>> >>> I just saw a post about VIA controllers triggering IOMMU errors. >>> >>> >>> Just want to also point out that the ax88179 will also trigger PTE >>> read errors when using the vendor's driver. >>> >>> I'm nowhere near an expert but I remember seeing that 'TD fragment' is >>> supported now or some such, which I take to mean that sg/tso should be >>> supported with usbnet ? >>> >>> I'm unclear on whether it can ever work with intel hosts because of an >>> errata ? >>> >>> Anyway for anyone that wants to see the error you can grab the vendor >>> driver: >>> >>> http://www.asix.com.tw/FrootAttach/driver/AX88179_178A_LINUX_DRIVER_v1.18.0_SOURCE.tar.bz2 >>> >>> >>> This driver was working recently-ish perhaps around the same time the >>> VIA controllers starting having iommu issues. >>> >>> >>> Regards, >>> >>> >>> Will >>> >>> >> > > _______________________________________________ > iommu mailing list > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linuxfoundation.org/mailman/listinfo/iommu > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
