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pci passthrough issue... "no IOMMU" error...

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Hello,

 

I am attempting to pass through my video but am having issues with "no IOMMU".

 

I am using an Asus P6T motherboard with an older i7 920 cpu. I have had this set up working with Windows HyperV with no issues but thought I would try to use UnRaid and XEN. Below are my config and details

 

 

XL CREATE error...

alloveru@alluNAS:~# xl create /mnt/cache/VMs/windows/win.cfg
Parsing config from /mnt/cache/VMs/windows/win.cfg
xc: info: VIRTUAL MEMORY ARRANGEMENT:
  Loader:        0000000000100000->000000000019ec84
  Modules:       0000000000000000->0000000000000000
  TOTAL:         0000000000000000->00000000ff800000
  ENTRY ADDRESS: 0000000000100000
xc: info: PHYSICAL MEMORY ALLOCATION:
  4KB PAGES: 0x0000000000000200
  2MB PAGES: 0x00000000000003fb
  1GB PAGES: 0x0000000000000002
libxl: error: libxl_pci.c:1045:libxl__device_pci_add: PCI device 0000:00:1b.0 cannot be assigned - no IOMMU?
libxl: error: libxl_pci.c:1045:libxl__device_pci_add: PCI device 0000:02:00.0 cannot be assigned - no IOMMU?
libxl: error: libxl_pci.c:1045:libxl__device_pci_add: PCI device 0000:02:00.1 cannot be assigned - no IOMMU?
Daemon running with PID 2163

 

 

sysconfig.cfg

default /syslinux/menu.c32
menu title Lime Technology
prompt 0
timeout 50
label unRAID OS
  
  kernel /bzimage
  append initrd=/bzroot
label unRAID OS Safe Mode (no plugins)
  kernel /bzimage
  append initrd=/bzroot unraidsafemode
label Memtest86+
  kernel /memtest
label Xen/unRAID OS
  menu default
  kernel /syslinux/mboot.c32 
  append /xen dom0_mem=2097152 --- /bzimage xen-pciback.hide=(00:1b.0)(02:00.0)(02:00.1) --- /bzroot

label Xen/unRAID OS Safe Mode (no plugins)
  kernel /syslinux/mboot.c32
  append /xen dom0_mem=2097152 --- /bzimage --- /bzroot unraidsafemode

 

win.cfg

name="Windows8"
builder="hvm"
vcpus=2
memory=4096
#disk = ['file:/mnt/cache/VMs/windows/Windows.img,hda,w']
disk = ['file:/mnt/cache/VMs/windows/Windows.img,hda,w', 'file:/mnt/cache/VMs/windows8_1.iso,hdc:cdrom,r']
vif = [ 'mac=00:16:3e:01:02:03,bridge=xenbr0' ]

boot="dc"

acpi = '1'
apic = '1'
viridian = '1'
xen_platform_pci='1'
sdl = '0'
vnc = '1'
vnclisten = '0.0.0.0'
vncpasswd = ''
stdvga = '0'
usb = '1'
usbdevice = 'tablet'

pci = ['00:1b.0','02:00.0','02:00.1']

on_poweroff="destroy"
on_reboot="restart"
on_crash="restart"

 

I have tried recreating my steps following the guides but I still can't seem to see what I am missing. I am sure it is something foolish...

 

Any help would be greatly appreciated. Thanks!

 

  • Author

follow up...

After some more reading... It appears that it may actually be the motherboard preventing it even thought VT-d is enabled... 

 

Are there work arounds?

 

thanks.

A Core i7-920 does not support vt-d  (AMD-Vi).  Not sure if that's the issue here or not, but it's generally required for pass-through ... although I know Xen has some difference in its requirements compared to other hypervisors.

 

... but I think it's likely that's your issue => and if so, there's no workaround except to switch to a CPU that supports vt-d

 

 

 

  • Author

Thanks, that was my fear....

 

Sent from my SGH-I747M using Tapatalk

 

 

A Core i7-920 does not support vt-d  (AMD-Vi).  Not sure if that's the issue here or not, but it's generally required for pass-through ... although I know Xen has some difference in its requirements compared to other hypervisors.

 

... but I think it's likely that's your issue => and if so, there's no workaround except to switch to a CPU that supports vt-d

The i7 920 does indeed support VT-D. With socket 1366 only certain chipsets actually supported VT-d, so it was a matter of the motherboard supporting (and supporting it properly) more than the CPU. It's different from how 1156/1155/1150 Intel setups work.

 

More info: http://www.intel.com/support/processors/xeon5k/sb/CS-031637.htm?wapkw=%28vt-d%29  and

http://www.intel.com/content/www/us/en/chipsets/server-chipsets/server-chipset-5500.html

 

I am using an ASUS Rampage III Extreme and an i7 920 in ESXi to passthrough PCIe cards (SATA, USB, GPU) to various VMs without any issue.

I've also done testing using Xen with Mint 16 as a host and it worked as well.

 

ASUS is notorious for buggering up support for VT-d between bios updates so you may want to try a different BIOS.

 

 

  • Author

Thanks for your replies.. But i am quitter... I swapped out the motherboard and CPU for a newer i7 and the error is gone!  However, video passthough still doesn't work, but audio does...  I will have to play more with it

 

Sent from my SGH-I747M using Tapatalk

 

 

The i7 920 does indeed support VT-D. More info:

 

Where did you confirm that?    The Intel ARK site, which is generally VERY accurate, shows vt-X support for the 9xx series CPUs, but does NOT list vt-d:

http://ark.intel.com/products/37147/Intel-Core-i7-920-Processor-8M-Cache-2_66-GHz-4_80-GTs-Intel-QPI

I think the key is this:

I am using an ASUS Rampage III Extreme and an i7 920 in ESXi to passthrough PCIe cards (SATA, USB, GPU) to various VMs without any issue.

I've also done testing using Xen with Mint 16 as a host and it worked as well.

so it would be from personal experience.

So it would seem.    Interesting that Intel doesn't show vt-d for this CPU => although it doesn't say "No" ... it just doesn't list it as one of the advanced technologies.

 

Core i7 920 definitely does support VT-D, I'm writing this right now running Xen on a i7 920. The problem is the P6T, I have the same board and IOMMU is totally broken on it. I spent some time trying to get it to work, but basically it never will until Asus fixes their firmware...which means it will never happen.

 

I picked up a cheap Intel DX58SO from ebay and it works no problem with Xen. Lesson learned? Better to go with Intel for this sort of thing and Asus doesn't care about properly supporting anything.

From the FAQ stickied to the top of this board...

 

IOMMU is what's required to use PCI passthrough (allowing Windows direct access to a graphics card for example). Intel K series processors are generally not supported, but in addition to the CPU supporting vt-d, your motherboard and more specifically your exact BIOS revision must as well.

 

It looks like you're out of luck alloveru.

So it would seem.    Interesting that Intel doesn't show vt-d for this CPU => although it doesn't say "No" ... it just doesn't list it as one of the advanced technologies.

At one point it used to say "Yes" when the processors were first released, but so many mobo manufacturers didn't include the option in their chipsets that Intel removed the field all together from their page due to customer complaints.

 

With 1366 Processors you're at the mercy of your motherboard manufacturer to make sure they setup vt-d correctly in the BIOS. The Rampage III Extreme with the latest bios works, I know the ASRock Supercomputer 1366 board works, and Intel DX58SO works as well. The first ASUS board I used didn't work, which was a P6T-Deluxe. At the time I was following the extremely long VMWare ESXi GPU passthrough thread, and someone confirmed the Rampage III Extreme as functional candidate for VT-d w/proper passthrough working. So I went on ebay and bought one.

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