Verifying Virtualization Extensions - Red Hat ENTERPRISE LINUX 5 - VIRTUALIZATION GUIDE Manual

Chapter 31. Tips and tricks
#boot=/dev/sda
default=0
timeout=15
#splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
serial ---unit=0 ---speed=115200 ---word=8 ---parity=no ---stop=1
terminal ---timeout=10 serial console
title Red Hat Enterprise Linux Server (2.6.17-1.2519.4.21.el5xen)
root (hd0,0)
kernel -/xen.gz-2.6.17-1.2519.4.21.el5 com1=115200,8n1 dom0_mem=256MB
module -/vmlinuz-2.6.17-1.2519.4.21.el5xen ro
root=/dev/VolGroup00/LogVol00
module -/initrd-2.6.17-1.2519.4.21.el5xen.img

31.6. Verifying virtualization extensions

Use this section to determine whether your system has the hardware virtualization extensions.
Virtualization extensions (Intel VT or AMD-V) are required for full virtualization.
Can I use virtualization without the virtualization extensions?
If hardware virtualization extensions are not present you can use Xen para-virtualization
with the Red Hat kernel-xen package.
1. Run the following command to verify the CPU virtualization extensions are available:
$ grep --E -'svm|vmx' -/proc/cpuinfo
2. Analyze the output.
• The following output contains a vmx entry indicating an Intel processor with the Intel VT
extensions:
flags -: fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush
dts acpi mmx fxsr sse sse2 ss ht
vmx est tm2 cx16 xtpr lahf_lm
• The following output contains an svm entry indicating an AMD processor with the AMD-V
extensions:
flags -: fpu tsc msr pae mce cx8 apic mtrr mca cmov pat pse36 clflush
mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow pni cx16
lahf_lm cmp_legacy svm cr8legacy ts fid vid ttp tm stc
If any output is received, the processor has the hardware virtualization extensions. However in
some circumstances manufacturers disable the virtualization extensions in BIOS.
The "flags:" content may appear multiple times for each hyperthread, core or CPU on the
system.
The virtualization extensions may be disabled in the BIOS. If the extensions do not appear or full
virtualization does not work refer to
328
tm syscall lm constant_tsc pni monitor ds_cpl
Procedure 34.1, "Enabling virtualization extensions in BIOS".