On 05.02.2015 13:00, Michal Privoznik wrote: > On 04.02.2015 22:32, Dennis Jacobfeuerborn wrote: >> Hi, >> today I tried to configure a guest using Virt-Manager and used the "copy >> host cpu configuration" option which resultet in a "Sandy Bridge" model. >> What I noticed is that for example the "aes" extension is not available >> in the guest even though it is available on the host cpu. >> >> This is what the host cpu looks like: >> >> model name : Intel(R) Xeon(R) CPU E5-2650 v3 @ 2.30GHz >> flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov >> pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx >> pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl >> xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor >> ds_cpl vmx smx est tm2 ssse3 fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 >> x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm >> abm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority >> ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid >> >> And this is what I get in the guest: >> >> model name : Intel Xeon E312xx (Sandy Bridge) >> flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov >> pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb lm >> constant_tsc pni ssse3 cx16 sse4_1 sse4_2 popcnt lahf_lm abm >> >> Is there a way to get closer to the hardware and get as many of the host >> features in the guest as possible? I never intend to do anything like >> live-migration with this guest so compatibility for that case is not a >> concern. >> > > I think this is XML snippet you're aiming for: > > <cpu mode='host-model'> > <model fallback='allow'/> > </cpu> Hm, according to the documentation mode='host-model' should not be used? "Beware, due to the way libvirt detects host CPU and due to the fact libvirt does not talk to QEMU/KVM when creating the CPU model, CPU configuration created using host-model may not work as expected. The guest CPU may differ from the configuration and it may also confuse guest OS by using a combination of CPU features and other parameters (such as CPUID level) that don't work. Until these issues are fixed, it's a good idea to avoid using host-model and use custom mode with just the CPU model from host capabilities XML." Regards, Dennis _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
