Hi, I encounter a problem that the eth can't be up in the VM by using VT-d. I boot the VM using "virsh create vt_d.xml". The VM could recongize the NIC which was assigned .then I do in VM as follows: #cat /sys/class/net/eth0/operstate down #ifconfig eth0 up #cat /sys/class/net/eth0/operstate down #ficonfig eth 10.100.0.5 #cat /sys/class/net/eth0/operstate down I look into the qemu log file ,find that : LC_ALL=C PATH=/usr/local/sbin:/usr/<div id=":6w">local/bin:/sbin:/bin:/usr/sbin:/usr/bin HOME=/ QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.12 -enable-kvm -m 512 -smp 1,sockets=1,cores=1,threads=1 -name vt_d_5 -uuid 05f608a3-f64f-2418-a90a-d611982c8336 -nodefaults -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/vt_d_5.monitor,server,nowait -mon chardev=monitor,mode=readline -rtc base=utc -boot c -drive file=/home/qinguan/exp/kvm_vtd/ubuntu_1.img,if=none,id=drive-virtio-disk0,boot=on,format=raw -device virtio-blk-pci,bus=pci.0,addr=0x3,drive=drive-virtio-disk0,id=virtio-disk0 -usb -device usb-mouse,id=input0 -vnc <a target="_blank">127.0.0.1:0</a> -vga cirrus -device pci-assign,host=00:19.0,id=hostdev0,bus=pci.0,addr=0x4 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 Failed to assign irq for "hostdev0": Operation not permitted Perhaps you are assigning a device that shares an IRQ with another device? Failed to assign irq for "hostdev0": Operation not permitted Perhaps you are assigning a device that shares an IRQ with another device? Failed to assign irq for "hostdev0": Operation not permitted Perhaps you are assigning a device that shares an IRQ with another device? Failed to assign irq for "hostdev0": Operation not permitted Perhaps you are assigning a device that shares an IRQ with another device? Failed to assign irq for "hostdev0": Operation not permitted maybe the VM can't access to the network because of Failed to assign irg for "hostdev0"? in kern.log : May 1 12:40:07 Optiplex-780 kernel: [ 3172.784803] e1000e 0000:00:19.0: PCI INT A disabled May 1 12:40:07 Optiplex-780 kernel: [ 3172.784863] pci-stub 0000:00:19.0: claimed by stub May 1 12:40:07 Optiplex-780 kernel: [ 3173.103965] pci-stub 0000:00:19.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21 May 1 12:40:07 Optiplex-780 kernel: [ 3173.204030] pci-stub 0000:00:19.0: restoring config space at offset 0x6 (was 0x1, writing 0xece1) May 1 12:40:07 Optiplex-780 kernel: [ 3173.204035] pci-stub 0000:00:19.0: restoring config space at offset 0x5 (was 0x0, writing 0xf7ad9000) May 1 12:40:07 Optiplex-780 kernel: [ 3173.204039] pci-stub 0000:00:19.0: restoring config space at offset 0x4 (was 0x0, writing 0xf7ae0000) May 1 12:40:07 Optiplex-780 kernel: [ 3173.204045] pci-stub 0000:00:19.0: restoring config space at offset 0x1 (was 0x100000, writing 0x100103) May 1 12:40:07 Optiplex-780 kernel: [ 3173.435751] assign device 0:0:19.0 May 1 12:44:24 Optiplex-780 kernel: [ 3430.568526] pci-stub 0000:00:19.0: restoring config space at offset 0x6 (was 0x1, writing 0xece1) May 1 12:44:24 Optiplex-780 kernel: [ 3430.568532] pci-stub 0000:00:19.0: restoring config space at offset 0x5 (was 0x0, writing 0xf7ad9000) May 1 12:44:24 Optiplex-780 kernel: [ 3430.568537] pci-stub 0000:00:19.0: restoring config space at offset 0x4 (was 0x0, writing 0xf7ae0000) May 1 12:44:24 Optiplex-780 kernel: [ 3430.568543] pci-stub 0000:00:19.0: restoring config space at offset 0x1 (was 0x100000, writing 0x100103) May 1 12:44:24 Optiplex-780 kernel: [ 3430.568561] pci-stub 0000:00:19.0: PCI INT A disabled root@Optiplex-780:/var/log/libvirt/qemu# cat /proc/interrupts CPU0 CPU1 CPU2 CPU3 0: 97 1 2 1 IO-APIC-edge timer 1: 2 0 0 0 IO-APIC-edge i8042 7: 0 0 0 0 IO-APIC-edge parport0 8: 1 0 0 0 IO-APIC-edge rtc0 9: 0 0 0 0 IO-APIC-fasteoi acpi 12: 1 2 1 0 IO-APIC-edge i8042 16: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb2 17: 5822 1952 3614 2233 IO-APIC-fasteoi uhci_hcd:usb4, uhci_hcd:usb7 18: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb8 22: 1 1 1 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb5 23: 1461 1299 1153 912 IO-APIC-fasteoi ehci_hcd:usb3, uhci_hcd:usb6 24: 268579 0 0 0 HPET_MSI-edge hpet2 25: 0 286310 0 0 HPET_MSI-edge hpet3 26: 0 0 210675 0 HPET_MSI-edge hpet4 27: 0 0 0 256688 HPET_MSI-edge hpet5 29: 1 0 0 0 DMAR_MSI-edge dmar1 30: 0 0 0 0 DMAR_MSI-edge dmar0 31: 0 0 0 0 DMAR_MSI-edge dmar2 35: 0 0 0 1 PCI-MSI-edge eth1 36: 1456 916 1323 1657 PCI-MSI-edge eth1-rx-0 37: 1031 772 1459 895 PCI-MSI-edge eth1-rx-1 38: 958 965 785 470 PCI-MSI-edge eth1-rx-2 39: 1319 557 1007 714 PCI-MSI-edge eth1-rx-3 40: 892 864 417 1134 PCI-MSI-edge eth1-tx-0 41: 414 749 998 606 PCI-MSI-edge eth1-tx-1 42: 307 921 375 332 PCI-MSI-edge eth1-tx-2 43: 966 693 396 502 PCI-MSI-edge eth1-tx-3 54: 7109 5755 5683 5609 PCI-MSI-edge ahci 55: 74 105 73 84 PCI-MSI-edge hda_intel 56: 1446 927 1108 870 PCI-MSI-edge i915 NMI: 0 0 0 0 Non-maskable interrupts LOC: 740 725 703 677 Local timer interrupts SPU: 0 0 0 0 Spurious interrupts PMI: 0 0 0 0 Performance monitoring interrupts PND: 0 0 0 0 Performance pending work RES: 665 679 714 547 Rescheduling interrupts CAL: 5332 408 5619 539 Function call interrupts TLB: 1880 2843 1788 3202 TLB shootdowns TRM: 0 0 0 0 Thermal event interrupts THR: 0 0 0 0 Threshold APIC interrupts MCE: 0 0 0 0 Machine check exceptions MCP: 5 5 5 5 Machine check polls ERR: 3 MIS: 0 root@Optiplex-780:/var/log/libvirt/qemu# I search the similarly problems that sharing the irg but never find a answer , and now I have no idea. How to solve the problem ,can you help me ? thanks.</div> best regards, qinguan vt_d.xml: <domain type='kvm'> <name>test</name> <description>just test using sriov!</description> <os> <type>hvm</type> <boot dev='hd'/> </os> <memory>524288</memory> <currentMemory>524288</<div id=":89">currentMemory> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <features><pae/><acpi/><apic/></features> <clock offset='utc'/> <devices> <input type='mouse' bus='usb'/> <disk type='file' device='disk'> <source file='/home/qinguan/exp/ubuntu_1.img'/> <target dev='hda' bus='virtio'/> </disk> <emulator>/usr/bin/kvm</emulator> <graphics type='vnc' port='-1'/> <hostdev mode='subsystem' type='pci' managed='yes'> <source> <address bus='0x0' slot='0x19' function='0x0'/> </source> </hostdev> </devices> </domain></div>