virtualization with kvm-84 on slackware 12.2

[GOD]Anck · 03-26-2009, 05:36 AM

I'm having some problems with virtualization using kvm-84 on slackware 12.2. I can't seem to install any guest operating system, qemu-system-x86_64 causes a general protection fault as soon as I start any installer. The system has an intel core2 quad cpu, and virtualization is enabled in bios. I run a slightly modified (highmem support) 2.6.27.7-smp kernel.

Here's what I did:

I downloaded kvm-84, compiled and installed it. This created the kvm kernel modules in /lib/modules/2.6.27.7-smp/extra/. I loaded the intel module with modprobe kvm-intel. /dev/kvm was created with root as owner and group. The kvm howto says to run qemu-system using sudo, but I created a kvm group instead and chgrp'd /dev/kvm to that group. I added my user account to the kvm group.

Code:

ls -la /dev/kvm
crw-rw---- 1 root kvm 10, 232 2009-03-26 09:58 /dev/kvm

groups
users floppy audio video cdrom kvm

Then I created an image and started an installer:

Code:

qemu-img create -f qcow image.img 10G
qemu-system-x86_64 -hda image.img -cdrom /path/to/install/iso -boot d -m 512

The install cd image boots, and I can navigate the menu, but when trying to start the installation, qemu-system-x86_64 causes a general protection fault:

Code:

Mar 26 10:06:52 quad kernel: general protection fault: 0000 [#3] SMP
Mar 26 10:06:52 quad kernel: Modules linked in: kvm_intel kvm snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss ppdev lp parport_pc parport fuse usbhid hid nvidia(P) snd_hda_intel uhci_hcd i2c_i801 snd_pcm agpgart i2c_core snd_timer ehci_hcd snd_page_alloc snd_hwdep sky2 thermal processor evdev thermal_sys button snd sg hwmon soundcore reiserfs
Mar 26 10:06:52 quad kernel:
Mar 26 10:06:52 quad kernel: Pid: 3705, comm: qemu-system-x86 Tainted: P      D   (2.6.27.7-smp #1)
Mar 26 10:06:52 quad kernel: EIP: 0060:[<f9365256>] EFLAGS: 00010246 CPU: 0
Mar 26 10:06:52 quad kernel: EIP is at vmx_save_host_state+0x156/0x1a0 [kvm_intel]
Mar 26 10:06:52 quad kernel: EAX: 00000900 EBX: 00000100 ECX: c0000080 EDX: 00000000
Mar 26 10:06:52 quad kernel: ESI: c0000080 EDI: f22d46e0 EBP: eed21e90 ESP: eed21e6c
Mar 26 10:06:52 quad kernel:  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Mar 26 10:06:52 quad kernel: Process qemu-system-x86 (pid: 3705, ti=eed20000 task=f3f3c6e0 task.ti=eed20000)
Mar 26 10:06:52 quad kernel: Stack: 00000000 00000000 00000900 00000000 00000800 00000000 f22d46e0 00000000
Mar 26 10:06:52 quad kernel:        f22d46e0 eed21ef0 f938cf70 00000000 00000001 c0578ffc eed21ed0 c014374d
Mar 26 10:06:52 quad kernel:        00000001 00000000 00000001 083c0000 f3f0b500 f22d46e0 c05598a8 f02f0000
Mar 26 10:06:52 quad kernel: Call Trace:
Mar 26 10:06:52 quad kernel:  [<f938cf70>] ? kvm_arch_vcpu_ioctl_run+0x310/0x9f0 [kvm]
Mar 26 10:06:52 quad kernel:  [<c014374d>] ? futex_wake+0xad/0xe0
Mar 26 10:06:52 quad kernel:  [<c017d6c4>] ? kfree+0x14/0xb0
Mar 26 10:06:52 quad kernel:  [<f9387dae>] ? kvm_vcpu_ioctl+0x44e/0x490 [kvm]
Mar 26 10:06:52 quad kernel:  [<c0152e5b>] ? __rcu_process_callbacks+0xb/0x170
Mar 26 10:06:52 quad kernel:  [<f9387960>] ? kvm_vcpu_ioctl+0x0/0x490 [kvm]
Mar 26 10:06:52 quad kernel:  [<c018d97d>] ? vfs_ioctl+0x2d/0x90
Mar 26 10:06:52 quad kernel:  [<c018dc4a>] ? do_vfs_ioctl+0x26a/0x2b0
Mar 26 10:06:52 quad kernel:  [<c01d6d58>] ? cap_file_ioctl+0x8/0x10
Mar 26 10:06:52 quad kernel:  [<c018dce7>] ? sys_ioctl+0x57/0x70
Mar 26 10:06:52 quad kernel:  [<c010325a>] ? syscall_call+0x7/0xb
Mar 26 10:06:52 quad kernel:  =======================
Mar 26 10:06:52 quad kernel: Code: 08 00 00 89 c1 09 d9 89 4d e4 89 d1 09 f1 be 80 00 00 c0 89 4d e8 8b 55 e8 89 f1 89 d0 31 d2 89 45 dc 8b 45 e4 89 55 e0 8b 55 dc <0f> 30 83 87 98 00 00 00 01 83 c4 18 5b 5e 5f 5d c3 b8 08 0c 00
Mar 26 10:06:52 quad kernel: EIP: [<f9365256>] vmx_save_host_state+0x156/0x1a0 [kvm_intel] SS:ESP 0068:eed21e6c
Mar 26 10:06:52 quad kernel: ---[ end trace 3c762b44fdc696cd ]---

Am I doing something wrong? How do I get this working? Install image used was a debian 5 netinst iso, I also tried an ubuntu 8.10 iso I had lying around and the same thing happened.

Didier Spaier · 03-26-2009, 05:53 AM

Did you check that your CPU support Intel VT ? It seems that some Core 2 do but others don't.

You could check on this page or @ http://processorfinder.intel.com/ or simply look at "cat /proc/cpuinfo|grep vmx"'s output.

The CPU should have the "vmx" flag if it is VT-able.

Mine is not

PS There is a SlackBuild for kvm-83 @ http://slackbuilds.org (it needs some editing to work with kvm-84 though).

EDIT This post was wrong about flag to check for, edited accordingly.

[GOD]Anck · 03-26-2009, 06:06 AM

/proc/cpuinfo shows the vmx flag which should indicate virtualization support. The kvm-intel module seems to load just fine:

Code:

modprobe kvm-intel
lsmod | grep kvm
kvm_intel              47592  2
kvm                   163952  1 kvm_intel

reptiler · 03-26-2009, 06:15 AM

From what I remember you'll be having problems with x86_64-guests when your OS is 32-bit, which Slackware is.
You still should be able to emulate a 64-bit system, but you won't enjoy the benefits which KQEmu or KVM are supposed to give you.
Thus, performance-wise, it would be better to use 32-bit guests.

I may be wrong about this, but that's how I remember it.

Chuck56 · 03-26-2009, 06:47 AM

In addition to your steps I created a udev rule.

file: /lib/udev/rules.d/65-kvm.rules

Code:

KERNEL=="kvm", NAME="%k", GROUP="kvm", MODE="0660"

Also you might be interested in the Slackbuild for KVM. Just remember to change the version number to 84 in the kvm.SlackBuild file if you go that route.

AlleyTrotter · 03-26-2009, 07:35 AM

I have no idea why your getting a seg fault, but I have several kvm virtual machines running on 12.2 with kernel 2.6.29
These are my notes on how to create install and boot them
Also a url which may help

To create an image for KVM
dd if=/dev/zero of=fedora.img bs=1k count=0 seek=16000000

To Install
/usr/bin/qemu-system-x86_64 -localtime -m 1024 -hda /img/fedora.img -cdrom /dev/cdrom -boot d

Or
/usr/bin/qemu-system-x86_64 -localtime -m 1024 -hda /img/winxp.img -cdrom /img/winxp_pro_us.iso -boot d

To boot
/usr/bin/qemu-system-x86_64 -localtime -m 1024 -hda /img/fedora.img -cdrom /dev/cdrom -soundhw es1370

http://alien.slackbook.org/dokuwiki/...slackware:qemu

I also have a kvm group of which I am a member and somewhere along the line a udev rule was created
KERNEL=="kvm", NAME="%k", GROUP="kvm", MODE="0660"
i believe by the slackbuild from sbo

john

[GOD]Anck · 03-26-2009, 04:21 PM

Quote:

Originally Posted by reptiler

From what I remember you'll be having problems with x86_64-guests when your OS is 32-bit, which Slackware is.
You still should be able to emulate a 64-bit system, but you won't enjoy the benefits which KQEmu or KVM are supposed to give you.
Thus, performance-wise, it would be better to use 32-bit guests.

I may be wrong about this, but that's how I remember it.

Ah yes, that was the problem, my install images were 64 bit. I got the 32 bit equivalent and it installed without a problem.

Thanks also to Chuck56 and AlleyTrotter for the udev rule, that will make life a little easier.