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Re: [Xen-users] VGA passthrough with USB passthrough

Hi, I have removed (00:02.0) from the grub argument line and been using:

xen-pciback.hide=(00:14.0) modprobe.blacklist=i915,xhci_pci,xhci_hcd

with DomU.cfg containing: gfx_passthru=1        pci=['00:02.0','00:14.0']

Now I am seeing the VGA passthrough working, but the Windows DomU is stuck at 100% CPU utilization in the kernel. Any ideas why?

I have PVDrivers installed, so I have added the pv list to this mail also.


On Mon, Oct 30, 2017 at 7:59 PM, Neil Sikka <neilsikka@xxxxxxxxx> wrote:

Hello, I am trying to passthrough 2 physical devices to a DomU: my integrated GPU that’s integrated into my CPU and my USB controller. These 2 devices are shown in lspci as follows:

00:02.0 VGA compatible controller: Intel Corporation Haswell Integrated Graphics Controller (rev 06)

00:14.0 USB controller: Intel Corporation Lynx Point USB xHCI Host Controller (rev 04)

My Setup:

xen_pciback compiled and loading as a module

Dom0 has the necessary backend drivers, so I’m assuming its pvops, which the docs say should be using “xen-pciback” rather than “pciback” in classic kernels.

Appended to my grub line: xen-pciback.hide=(00:02.0)(00:14.0) modprobe.blacklist=i915,xhci_pci,xhci_hcd

i915.ko is renamed to _i915.ko because it gets loaded despite modprobe.blacklist argument, and I think i915 is competing with xen-pciback.ko for (00:02.0)

DomU.cfg has: gfx_passthru=1        pci=['00:02.0','00:14.0']

Before starting DomU, I run xl pci-assignable-add 00:02.0 && xl pci-assignable-add 00:14.0

I have gotten each passthrough to independently work correctly on my computer in the past, so I know the hardware supports it. When combining the USB and GPU passthrough, I am seeing different things online and am confused about the correct way to configure my Dom0/DomUs. Here:


it says nothing about passing the BDF of the iGPU to xen-pciback.hide= argument in grub. However that page links to a document, here:


which says to pass the BDF of the discrete GPU 01:00.0 to the grub xen-pciback.hide parameter. When I use xen-pciback.hide=(00.02.0)(00:14.0), I see 23 "vgaarb: this pci device is not a vga device" errors when I boot Dom0 (which might be related to the fact that lspci reports 23 devices?). When I remove (00:02.0), I dont see the vgaarb errors, but in both cases, when I create the DomU, the VGA passthrough works. 

When I use xen-pciback.hide=(00.02.0)(00:14.0) and try to passthrough both together, I also get SATA write errors.

How can correctly I passthrough both the iGPU and the USB controller to avoid SATA errors leading to disk corruption and vgaarb errors?

Thank You.


Twitter: @neilsikka
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