Virtual-Machine
即使啟用了 Intel IOMMU，virt-manager PCI passthrough 也會給出錯誤“No IOMMU Found”
我正在嘗試在 virt-manager 中設置 PCI 直通，以授予我的 Debian Wheezy 來賓 VM 訪問筆記型電腦的 Intel Centrino N 無線網卡的權限。
Debian 預設核心啟用了 Intel IOMMU，我已
intel_iommu=on在啟動時傳遞給核心（通過編輯/etc/default/grub和設置GRUB_CMDLINE_LINUX="intel_iommu=on"，然後執行grub-update）…查看 dmesg 以驗證 IOMMU 確實已啟用，我看到：
[ 0.000000] Intel-IOMMU: enabled…我嘗試按照此處的說明進行操作，並在將 PCI 設備添加到 VM（即
virsh nodedev-detach pci_0000_01_00_0）之前使用 virsh 將其分離，以確保確定。但是，在為該無線網卡啟用 PCI 直通的情況下，我根本無法啟動來賓 VM，並且我收到以下錯誤（來自
/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**這是來自的完整輸出
/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我認為“無法連接到監視器”消息在某種程度上是相關的。如果我使用 virt-manager 將無線網卡添加為 PCI 設備，而沒有先將其分離
virsh nodedev-detach（如上所述），那麼我會從 virt-manager 收到一條錯誤消息：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…
/var/log/libvirt/libvirtd.log在這種情況下出現的所有內容是：2014-09-22 04:48:26.387+0000: 2985: error : qemuMonitorIORead:523 : Unable to read from monitor: Connection reset by peer如果有幫助，這裡是一些相關的輸出
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另外，為了清楚起見，在將無線網卡添加為 PCI 直通設備之前，我能夠很好地啟動到這個虛擬機，一旦我通過 virt-manager 刪除它，一切都會恢復正常工作。
有誰知道如何解決這個問題？謝謝！
其實我剛發現這個處理器支持VT-x但不支持VT-d，所以不能做IOMMU。