# Can't start KVM domains [SOLVED]

## mgnut57

KVM was working on my system, but I have not used it for quite some time. Now, however, KVM domains won't start:

virsh start Centos6Samba

error: Failed to start domain Centos6Samba

error: unsupported configuration: Domain requires KVM, but it is not available. Check that virtualization is enabled in the host BIOS, and host configuration is setup to load the kvm modules.

I have an AMD machine and virtualization is enabled:

grep svm /proc/cpuinfo 

flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl nonstop_tsc extd_apicid aperfmperf pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt arat cpb hw_pstate npt lbrv svm_lock nrip_save pausefilter

KVM is built into the kernel (not a module):

zgrep -i "kvm\|virtualiz" /proc/config

CONFIG_HAVE_KVM=y

CONFIG_VIRTUALIZATION=y

libvirtd is running:

 ps -Af | grep [l]ibvirt

root      2039     1  4 19:45 ?        00:01:03 /usr/sbin/libvirtd -d

Why won't the KVM domains start?Last edited by mgnut57 on Thu Feb 13, 2014 3:44 am; edited 1 time in total

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## bbgermany

Hi,

you need the KVM_AMD for your System as well. You need to enabel at least CONFIG_KVM_AMD in your Kernelconfig for getting this running.

bb

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## mgnut57

 *bbgermany wrote:*   

> Hi,
> 
> you need the KVM_AMD for your System as well. You need to enabel at least CONFIG_KVM_AMD in your Kernelconfig for getting this running.
> 
> bb

 

Thanks. The KVM_AMD option was not displayed, but I tracked that down to the lack of high resolution timer support. Recompiling now!

Finished re-building the kernel, rebooted and now KVM domains start. The problem was that the KVM_AMD option was not available in the configuration GUI because HIGH_RES_TIMERS wasn't enabled.Last edited by mgnut57 on Thu Feb 13, 2014 3:43 am; edited 1 time in total

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## Hu

The solution from bbgermany is correct.  The symbol CONFIG_HAVE_KVM means that the architecture is capable of enabling KVM, not that KVM is enabled.

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