[CentOS-virt] PCI Passthrough not working

Fri Jun 24 10:55:19 UTC 2016
George Dunlap <dunlapg at umich.edu>

On Wed, Jun 22, 2016 at 11:49 AM, Francis Greaves <francis at choughs.net> wrote:
> More information...
> I have pcifront showing as a module in the DomU and the usb shows in dmesg
> as:
> [    3.167543] usbcore: registered new interface driver usbfs
> [    3.167563] usbcore: registered new interface driver hub
> [    3.167585] usbcore: registered new device driver usb
> [    3.196056] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002
> [    3.196060] usb usb1: New USB device strings: Mfr=3, Product=2,
> SerialNumber=1
> [    3.196064] usb usb1: Product: EHCI Host Controller
> [    3.196068] usb usb1: Manufacturer: Linux 3.2.0-4-686-pae ehci_hcd
> [    3.196071] usb usb1: SerialNumber: 0000:00:00.0
> [    3.508036] usb 1-1: new high-speed USB device number 2 using ehci_hcd
> [   19.064072] usb 1-1: device not accepting address 2, error -110
> [   19.176070] usb 1-1: new high-speed USB device number 3 using ehci_hcd
> [   34.732067] usb 1-1: device not accepting address 3, error -110
> [   34.844082] usb 1-1: new high-speed USB device number 4 using ehci_hcd
> [   45.280073] usb 1-1: device not accepting address 4, error -110
> [   45.392067] usb 1-1: new high-speed USB device number 5 using ehci_hcd
> [   55.824112] usb 1-1: device not accepting address 5, error -110

Can you post your question with your guest config file, lspci in dom0,
and lspci in your domU to xen-users?  There will be a lot more
eyeballs there to help you get things sorted out.

> I am looking at xl dmesg in Dom0 where there are some messages relating to
> the PCI usb:
> [VT-D] It's disallowed to assign 0000:00:1a.0 with shared RMRR at 7b800000
> for Dom6.
> (XEN) XEN_DOMCTL_assign_device: assign 0000:00:1a.0 to dom6 failed (-1)
> (XEN) [VT-D] It's risky to assign 0000:00:1a.0 with shared RMRR at 7b800000
> for Dom7.
> (XEN) [VT-D] It's risky to assign 0000:00:1a.0 with shared RMRR at 7b800000
> for Dom8.
> (XEN) [VT-D] It's risky to assign 0000:00:1a.0 with shared RMRR at 7b800000
> for Dom9.
> (XEN) [VT-D] It's risky to assign 0000:00:1a.0 with shared RMRR at 7b800000
> for Dom10.

This looks like you tried once to start your guest without
"rdm_policy=relaxed" (which failed), and then tried it four times with
"rdm_policy=relaxed" (which succeeded).  Other than warning that
there's a shared RMRR (which could potentially be a security risk),
everything here looks normal.

There's a possibility that the shared RMRR is what's tripping things
up, but it's not very likely.

> In the
> as an aside... I just get blocks on the screen after the scrubbing message,
> and no text. I see there is a message:
> (XEN) Xen is relinquishing VGA console.
> How can I prevent this? Is there something wrong with my /etc/default/grub
>
> ...
> GRUB_CMDLINE_LINUX="crashkernel=auto intremap=no_x2apic_optout"
> GRUB_CMDLINE_XEN_DEFAULT="dom0_mem=13312M,max:14336M dom0_max_vcpus=6
> dom0_vcpus_pin"
> GRUB_GFXMODE=1024x768
> GRUB_GFXPAYLOAD_LINUX=keep
> GRUB_CMDLINE_LINUX_XEN_REPLACE_DEFAULT="console=hvc0 earlyprintk=xen"

Could you post this as a separate message to xen-users?

Thanks.
 -George