mjhjmtu

I am trying to set up PCI passthrough in virt-manager to grant my Debian Wheezy guest VM access to my laptop's Intel Centrino N wireless card.

The Debian default kernel has Intel IOMMU enabled, and I have passed intel_iommu=on to the kernel at boot (by editing /etc/default/grub and setting GRUB_CMDLINE_LINUX="intel_iommu=on", and then running grub-update) ...

Looking at dmesg to verify that IOMMU is indeed enabled, I see: [ 0.000000] Intel-IOMMU: enabled ...

I tried following the instructions here, and used virsh to detach the PCI device before adding it to the VM (i.e. virsh nodedev-detach pci_0000_01_00_0) just to be sure.

However, I cannot boot into the guest VM at all with PCI passthrough enabled for this wireless card, and I am getting the following error (from /var/log/libvirt/libvirtd.log):

2014-09-22 04:45:19.325+0000: 2990: error : qemuMonitorOpenUnix:305 : failed to connect to monitor socket: No such process
2014-09-22 04:45:19.325+0000: 2990: error : qemuProcessWaitForMonitor:1593 : internal error process exited while connecting to monitor: char device redirected to /dev/pts/1
**No IOMMU found. Unable to assign device "hostdev0"
kvm: -device pci-assign,host=01:00.0,id=hostdev0,configfd=22,bus=pci.0,addr=0x7: Device 'pci-assign' could not be initialized**

Here is the full output from /var/log/libvirt/qemu/:

2014-09-22 04:10:47.002+0000: starting up
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin HOME=/ QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-1.1 -cpu Nehalem,+rdtscp,+avx,+osxsave,+xsave,+tsc-deadline,+x2apic,+pdcm,+xtpr,+tm2,+est,+vmx,+ds_cpl,+monitor,+dtes64,+pclmuldq,+pbe,+tm,+ht,+ss,+acpi,+ds,+vme -enable-kvm -m 2500 -smp 4,sockets=4,cores=1,threads=1 -name DebianStableSandbox -uuid c18e2808-c98a-2b4d-54f1-00977d3ec1d2 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/DebianStableSandbox.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/libvirt/images/DebianNET.img,if=none,id=drive-virtio-disk0,format=raw -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive if=none,id=drive-ide0-1-0,readonly=on,format=raw -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev tap,fd=21,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:c5:4a:a9,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -device usb-tablet,id=input0 -vnc 127.0.0.1:0 -vga cirrus -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device pci-assign,host=01:00.0,id=hostdev0,configfd=22,bus=pci.0,addr=0x7 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6
char device redirected to /dev/pts/1
No IOMMU found. Unable to assign device "hostdev0"
kvm: -device pci-assign,host=01:00.0,id=hostdev0,configfd=22,bus=pci.0,addr=0x7: Device 'pci-assign' could not be initialized
2014-09-22 04:10:47.610+0000: shutting down

I think that the "failed to connect to monitor" message is somehow related. If I use virt-manager to add the wireless card as a PCI device, without first detaching it with virsh nodedev-detach (as mentioned above), then I get an error message from virt-manager saying:

Error starting domain: Unable to read from monitor: Connection reset by peer

Traceback (most recent call last):
 File "/usr/share/virt-manager/virtManager/asyncjob.py", line 45, in cb_wrapper
 callback(asyncjob, *args, **kwargs)
 File "/usr/share/virt-manager/virtManager/asyncjob.py", line 66, in tmpcb
 callback(*args, **kwargs)
 File "/usr/share/virt-manager/virtManager/domain.py", line 1114, in startup
 self._backend.create()
 File "/usr/lib/python2.7/dist-packages/libvirt.py", line 620, in create
 if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
libvirtError: Unable to read from monitor: Connection reset by peer

... and all that shows up in /var/log/libvirt/libvirtd.log in this case is: 2014-09-22 04:48:26.387+0000: 2985: error : qemuMonitorIORead:523 : Unable to read from monitor: Connection reset by peer

In case it is helpful, here is some of the relevant output from lspci -v:

00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
 Subsystem: Dell Device 04d8
 Flags: bus master, fast devsel, latency 0
 Capabilities: [e0] Vendor Specific Information: Len=0c <?>
 Kernel driver in use: agpgart-intel

00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5) (prog-if 00 [Normal decode])
 Flags: bus master, fast devsel, latency 0
 Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
 Memory behind bridge: d1600000-d16fffff
 Capabilities: [40] Express Root Port (Slot+), MSI 00
 Capabilities: [80] MSI: Enable- Count=1/1 Maskable- 64bit-
 Capabilities: [90] Subsystem: Dell Device 04d8
 Capabilities: [a0] Power Management version 2
 Kernel driver in use: pcieport

01:00.0 Network controller: Intel Corporation Centrino Wireless-N 1030 [Rainbow Peak] (rev 34)
 Subsystem: Intel Corporation Centrino Wireless-N 1030 BGN
 Flags: fast devsel, IRQ 16
 Memory at d1600000 (64-bit, non-prefetchable) [size=8K]
 Capabilities: [c8] Power Management version 3
 Capabilities: [d0] MSI: Enable- Count=1/1 Maskable- 64bit+
 Capabilities: [e0] Express Endpoint, MSI 00
 Capabilities: [100] Advanced Error Reporting
 Capabilities: [140] Device Serial Number bc-77-37-ff-ff-0d-3f-90
 Kernel driver in use: pci-stub

Also, just to be clear, I was able to boot into this VM fine before adding the wireless card as a PCI passthrough device, and once I remove it via virt-manager, everything goes back to working as usual.

Does anyone have any idea how to fix this? Thanks!

Actually, I just found out that this processor supports VT-x but not VT-d, so I can't do IOMMU.