On 07/23/2012 12:46 PM, Johan & Katrien Dewaele² wrote:
Hi,
I'm confused !
I'm trying to get Line 6 Edit HD 300 software for a Line 6 multi-effect-board
for guitar to run on a virtual machine on my Debian testing
- kernel 3.4.6 box.
1° I tried virtualbox version 4.1.18-78361~Debian~wheezy
with windows XP as guest:
The program runs, I can adjust all parameters/knobs but
have a problem synchronising data (pre-sets) between
the software and the Line6 hardware: pre-sets are not
loaded from the effect-board, adjustments made on the
HD 300 edit software can not be saved to the device (hardware).
So communication between soft and hardware is not optimal.
2° So I was suggested to try kvm-qemu as this software is
being developed more actively
Hence my confusion: Can somebody tell me what the
difference is between : qemu and qemu-kvm ?
I have following versions installed:
qemu 1.1.0+dfsg-1 fast processor emulator
qemu-kvm 1.1.0+dfsg-3 Full virtualization on x86 hardware
I start the guest OS as follows: (don't mind the difference in
shared samba-folder, and the extra parameters for
having a network interface in qemu)
$kvm -smb /home/dewaele/bin/shared -m 512 -smp 4
-localtime -device piix4-usb-uhci -usb -usbdevice
host:0e41:5057 /mnt/Windisk/QEMU/qemu_XP3
$qemu -netdev user,id=usernet -device
rtl8139,netdev=usernet -smb /mnt/MijnDocsDisk -m 512
-smp 4 -localtime -device piix4-usb-uhci -usb -usbdevice
host:0e41:5057 -machine accel=kvm,kernel_irqchip=on -option-rom
/usr/share/seabios/optionrom/kvmvapic.bin /mnt/Windisk/QEMU/qemu_XP3
For both I use kvm acceleration-virtualisation (I notice
an important performance increase when adding the
machine accel parameter in qemu), but I do not see any
difference in the way the Line 6 program or Windows XP
behaves. I am using the same windows XP image.
But hey, both programs seem to be allready better than
virtualbox !!!! synchronisation is somewhat better but
still not good enough.
As with both qemu and kvm-qemu the Line6 software is not
really behaving as it should, I would like to choose
what the best solution is, and will be ....
3° I tried googling the matter: most people seem also
confused.... ;-) : has kvm been merged with qemu or
will this happen in the future? Or is kvm a step ahead
of qemu? Is there still a difference in code? Is qemu
only hardware emulation and not real virtualisation as kvm should
be (what is the difference)?
4° also if anybody has more look to have this software
communicate better with the Line 6 hardware and would
like to share: I would appreciate any help or advice
or suggestions. Hey, I'm open to everything ! :-)
Best regards and thanks in advance,
Johan
i think your asking two questions here. one is whats the
difference between qemu and qemu-kvm. another thats how
to improve the performance of a usb device in the guest.
these days, there aren't many differences between qemu and
qemu-kvm. qemu started first and was a general purpose
machine emulator but without any acceleration it was
rather slow. it has the ability to emulate a wide
variety of platforms and hardware including x86, arm, powerpc,
mips, etc.
i think 'kvm' is an overloaded term and i think of it just
as a linux kernel module that allows software to use the
virtualization extensions in modern processors. 'kvm' is
also used to refer to the larger ecosystem of things
related to virtualization using the kvm kernel module.
qemu-kvm is a fork of qemu that added the ability for qemu
to use the kvm kernel module to accelerate some guests
and improve performance. there has been a bit of work to
merge the changes qemu-kvm did into the upstream qemu
code-base and a lot of the work has been completed. there are
still a few things that qemu-kvm has that qemu does not have. qemu
already has the ability to use the kvm kernel module for
acceleration.
unfortunately, i don't have a lot of experience using usb
devices with qemu/qemu-kvm guests and haven't ever tried
the usb passthru. if you have newer hardware with the
proper support and can spare a few usb ports, you could
try giving the entire usb controller to the guest. that might
give you better performance. http://www.linux-kvm.org/page/How_to_assign_devices_with_VT-d_in_KVM
gives some information about it. i followed those basics
steps to pass a usb3 controller through to a windows
guest and tested a usb stick in windows.
i hope that all makes sense and answers your questions.
mike
Mike, thanks for your info and effort to go through my confused mail ;-)
Tried your suggestions on usb passthrough but this is not going to work on my pc :
Allthough dmesg tells me:
Kernel command line: auto BOOT_IMAGE=Linux-3.4.6 ro root=805 selinux=0 intel_iommu=on
Intel-IOMMU: enabled
virtualbox tells me:
vboxpci: IOMMU not found (not registered)
and qemu:
# qemu -netdev user,id=usernet -device rtl8139,netdev=usernet -smb /mnt/MijnDocsDisk -m 512 -smp 4 -localtime -device piix4-usb-uhci -usb -usbdevice host:0e41:5057 -machine accel=kvm,kernel_irqchip=on -option-rom /usr/share/seabios/optionrom/kvmvapic.bin -device pci-assign,host=00:1d.0 /mnt/Windisk/QEMU/qemu_XP3
qemu: -device pci-assign,host=00:1d.0: Parameter 'driver' expects device type
and kvm:
# kvm -smb /mnt/MijnDocsDisk -m 512 -smp 4 -localtime -device piix4-usb-uhci -usb -usbdevice host:0e41:5057 -machine accel=kvm,kernel_irqchip=on -option-rom /usr/share/seabios/optionrom/kvmvapic.bin -device pci-assign,host=00:1d.0 /mnt/Windisk/QEMU/qemu_XP3
No IOMMU found. Unable to assign device "(null)"
**
ERROR:/tmp/buildd/qemu-kvm-1.1.0+dfsg/qom/object.c:389:object_delete: assertion failed: (obj->ref == 0)
I have no option in BIOS to enable/disable VT-d
So I suspect that my box (or CPU or chipset or BIOS) does not support VT-d.
Excuse me also for making a separate post but I'm not subscribed to the list.
Thanks for your time.
Johan
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