There's rarely much harm to hardware in playing around with anything
other than the fan control / bios / soldering, though obviously you can
kill your OS installation (but that's just one reason why we love
VM's!). I wouldn't expect much success as the four network devices are
likely together because they share resource/control functions. As you
say - you will have to trick the system into thinking they are isolated
using the ACS isolation patch. Maybe somebody more experienced can give
a clearer answer though as I've never used that patch but I'm deeply
inclined to recommend a virtualised solution as it's robust .. scalable
and far easier to maintain.
For example, just run the 4 network cards on the host and make virtual
networks or bridge for the clients. Routing is a complex problem and has
to be handled somehwere so it's better you know where plus with 4
network cards I can imagine the the performance impact (latency or
throughput) of using virtual nets/bridges on all computers/routers will
round off to 0 when measured against the overhead introduced by the
cards not having unique 8GT/s connections to their destinations.
I can think of cases where it would be worth the effort but I suggest
you have a dig around in some of the network virtualisation documents
(arch is quite a good place to start if I remember). It gets very scary
very quickly even before you try to pass them through separately and if
you've got 20,000 of these you'll need more knowledgeable help than me.
On 26/03/16 11:28, YAEGASHI Takeshi wrote:
Hello,
I have a fitlet http://www.fit-pc.com/web/products/fitlet/ with 4 GbE
(I211) ports and wanted to passthrough some of them to KVM guests, ie
assign one I211 to each guests. I've tried various configurations
with libvirt/kvm but no luck so far.
After reading http://vfio.blogspot.jp/2014/08/iommu-groups-inside-and-out.html
I've got sure that there's a problem in IOMMU groups. Actually all of
I211 and AMD's PCI bridge [1022:156b] share the same iommu_group 2.
$ lspci -tv
-[0000:00]-+-00.0 Advanced Micro Devices, Inc. [AMD] Device 1566
+-00.2 Advanced Micro Devices, Inc. [AMD] Device 1567
+-01.0 Advanced Micro Devices, Inc. [AMD/ATI] Mullins [Radeon R6
Graphics]
+-01.1 Advanced Micro Devices, Inc. [AMD/ATI] Kabini HDMI/DP Audio
+-02.0 Advanced Micro Devices, Inc. [AMD] Device 156b
+-02.2-[01]----00.0 Intel Corporation I211 Gigabit Network
Connection
+-02.3-[02]----00.0 Intel Corporation I211 Gigabit Network
Connection
+-02.4-[03]----00.0 Intel Corporation I211 Gigabit Network
Connection
+-02.5-[04]----00.0 Intel Corporation I211 Gigabit Network
Connection
+-08.0 Advanced Micro Devices, Inc. [AMD] Device 1537
+-10.0 Advanced Micro Devices, Inc. [AMD] FCH USB XHCI Controller
+-11.0 Advanced Micro Devices, Inc. [AMD] FCH SATA Controller
[AHCI mode]
+-12.0 Advanced Micro Devices, Inc. [AMD] FCH USB EHCI Controller
+-13.0 Advanced Micro Devices, Inc. [AMD] FCH USB EHCI Controller
+-14.0 Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller
+-14.2 Advanced Micro Devices, Inc. [AMD] FCH Azalia Controller
+-14.3 Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge
+-14.7 Advanced Micro Devices, Inc. [AMD] FCH SD Flash Controller
+-18.0 Advanced Micro Devices, Inc. [AMD] Device 1580
+-18.1 Advanced Micro Devices, Inc. [AMD] Device 1581
+-18.2 Advanced Micro Devices, Inc. [AMD] Device 1582
+-18.3 Advanced Micro Devices, Inc. [AMD] Device 1583
+-18.4 Advanced Micro Devices, Inc. [AMD] Device 1584
\-18.5 Advanced Micro Devices, Inc. [AMD] Device 1585
$ find /sys/kernel/iommu_groups -type l
/sys/kernel/iommu_groups/0/devices/0000:00:00.0
/sys/kernel/iommu_groups/1/devices/0000:00:01.0
/sys/kernel/iommu_groups/1/devices/0000:00:01.1
/sys/kernel/iommu_groups/2/devices/0000:00:02.0
/sys/kernel/iommu_groups/2/devices/0000:00:02.2
/sys/kernel/iommu_groups/2/devices/0000:00:02.3
/sys/kernel/iommu_groups/2/devices/0000:00:02.4
/sys/kernel/iommu_groups/2/devices/0000:00:02.5
/sys/kernel/iommu_groups/2/devices/0000:01:00.0
/sys/kernel/iommu_groups/2/devices/0000:02:00.0
/sys/kernel/iommu_groups/2/devices/0000:03:00.0
/sys/kernel/iommu_groups/2/devices/0000:04:00.0
/sys/kernel/iommu_groups/3/devices/0000:00:08.0
/sys/kernel/iommu_groups/4/devices/0000:00:10.0
/sys/kernel/iommu_groups/5/devices/0000:00:11.0
/sys/kernel/iommu_groups/6/devices/0000:00:12.0
/sys/kernel/iommu_groups/7/devices/0000:00:13.0
/sys/kernel/iommu_groups/8/devices/0000:00:14.0
/sys/kernel/iommu_groups/8/devices/0000:00:14.2
/sys/kernel/iommu_groups/8/devices/0000:00:14.3
/sys/kernel/iommu_groups/8/devices/0000:00:14.7
/sys/kernel/iommu_groups/9/devices/0000:00:18.0
/sys/kernel/iommu_groups/9/devices/0000:00:18.1
/sys/kernel/iommu_groups/9/devices/0000:00:18.2
/sys/kernel/iommu_groups/9/devices/0000:00:18.3
/sys/kernel/iommu_groups/9/devices/0000:00:18.4
/sys/kernel/iommu_groups/9/devices/0000:00:18.5
I'm running Ubuntu 14.04 with xenial kernel 4.4.0-13, libvirt 1.2.2,
qemu 2.0.0. Using vfio-pci simply failed:
qemu-system-x86_64: -device
vfio-pci,host=01:00.0,id=hostdev0,bus=pci.0,addr=0x3: vfio: error, group 2 is
not viable, please ensure all devices within the iommu_group are bound to their
vfio bus driver.
qemu-system-x86_64: -device
vfio-pci,host=01:00.0,id=hostdev0,bus=pci.0,addr=0x3: vfio: failed to get group
2
qemu-system-x86_64: -device
vfio-pci,host=01:00.0,id=hostdev0,bus=pci.0,addr=0x3: Device initialization
failed.
qemu-system-x86_64: -device
vfio-pci,host=01:00.0,id=hostdev0,bus=pci.0,addr=0x3: Device 'vfio-pci' could
not be initialized
Using legacy KVM device assignment with <driver name='kvm'/> also
failed with unclear reason "Invalid argument":
qemu-system-x86_64: -device
pci-assign,configfd=24,host=01:00.0,id=hostdev0,bus=pci.2,addr=0x2: Failed to assign
device "hostdev0" : Invalid argument
qemu-system-x86_64: -device
pci-assign,configfd=24,host=01:00.0,id=hostdev0,bus=pci.2,addr=0x2: Device
initialization failed.
qemu-system-x86_64: -device
pci-assign,configfd=24,host=01:00.0,id=hostdev0,bus=pci.2,addr=0x2: Device
'kvm-pci-assign' could not be initialized
After some googling I've learned that legacy KVM assignment also
refuses to work for this configuration since kernel 4.2
https://lkml.org/lkml/2015/11/12/661 . With older kernel 3.19 this
configuration worked as expected.
Is there any chance for me to achieve single I211 passthrough with
recent kernels? Because the hardware has no flexibility on the bus
topologies, the only possible way would be patching the kernel (ACS
override or PCI quirks). Is it safe? Does anyone have any info on
the IOMMU capability of device/bridge/chipset in question?
Regards,
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