Hi, I am trying to use x86 machine to create VMs. But one error occurs. [root@mcd kvm-test]# virsh create test.xml error: Failed to create domain from test.xml error: unknown OS type hvm My xml file is as the following: <domain type='kvm'> <name>test</name> <memory>524288</memory> <memorybacking> <hugepages/> </memorybacking> <vcpu>2</vcpu> <os> <type arch='x86_64' machine='pc'>hvm</type> </os> <features> <acpi/> </features> <clock offset='utc'/> <devices> <emulator>/usr/bin/qemu-system-x86_64</emulator> <disk type='file' device='disk' > <driver name='qemu' type='raw'/> <source file='/home/zhlbj/kvm-test/disk1'/> <target dev='sda' bus='scsi'/> </disk> <interface type='bridge'> <source bridge='virbr0'/> <mac address='52:54:00:19:bc:0c'/> </interface> <serial type='pty'> <target port='0'/> </serial> <console type='pty'> <target type='serial' port='0'/> </console> <memballoon model="none"/> </devices> </domain> I check kvm module, it is available. [root@mcd kvm-test]# lsmod |grep kvm kvm_intel 119308 4 kvm 344876 1 kvm_intel But I tried the capabilities, it is not right. There is no guest capabilities. <capabilities> <host> <uuid>d4ff0166-0f8b-e111-ab17-78a277034000</uuid> <cpu> <arch>x86_64</arch> <model>Nehalem</model> <vendor>Intel</vendor> <topology sockets='1' cores='4' threads='1'/> <feature name='rdtscp'/> <feature name='avx'/> <feature name='osxsave'/> <feature name='xsave'/> <feature name='tsc-deadline'/> <feature name='x2apic'/> <feature name='pdcm'/> <feature name='xtpr'/> <feature name='tm2'/> <feature name='est'/> <feature name='smx'/> <feature name='vmx'/> <feature name='ds_cpl'/> <feature name='monitor'/> <feature name='dtes64'/> <feature name='pclmuldq'/> <feature name='pbe'/> <feature name='tm'/> <feature name='ht'/> <feature name='ss'/> <feature name='acpi'/> <feature name='ds'/> <feature name='vme'/> </cpu> <power_management> <suspend_mem/> <suspend_disk/> <suspend_hybrid/> </power_management> <migration_features> <live/> <uri_transports> <uri_transport>tcp</uri_transport> </uri_transports> </migration_features> <secmodel> <model>selinux</model> <doi>0</doi> </secmodel> </host> </capabilities> This problem occurs some times. When I tried to find this problem, it didn't occur. Now it occurs again. It's a little strange. Is there anything I miss? -- Best Regards Li IBM LTC, China System&Technology Lab, Beijing