# KVM and Windows 7 x64

## jserink

Hi All:

I had a few BSODs with my new install of Windows7 x64 running under qemu-kvm-0.15.1-r1. The error was:

qemu-system-x86_64: virtio_ioport_write: unexpected address 0x13 value 0x1

I was using both the virtio network and SCSI drivers so I thought it was the network driver so rebooted in using the e1000 adapter rather than the virtio adapter.

I then proceeded to do a bunch of testing using samba and then ftp via the VDE tap interface technique. Here are my results using a 500Mbyte test file:

Samba:

e1000 windows guest to Linux host, ~148Mbps,

e1000 linux host to windows guest, ~121Mbps,

e1000 ftp windows guest to linux host, ~800Mbps,

e1000 ftp linux host to windows guest, ~650Mbps.

virtio windows guest to Linux host, ~284Mbps,

virtio linux host to windows guest, ~274bps,

virtio ftp windows guest to linux host, ~800Mbps,

virtio ftp linux host to windows guest, ~650Mbps.

SMB gets buried with ftp, not sure why.

I was trying to reproduce the BSOD but was unable to and got these numbers in that pursuit so thought I'd share them.

Cheers,

john

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## Mad Merlin

FWIW, both the IDE and virtio drivers are strongly prefered to the SCSI drivers for emulated disks. The reason is that the SCSI implementation in KVM gets very little testing and love, so it's probably slower and buggier.

Also, you'll probably find that SMB is slower than FTP on real hardware too, SMB was never really designed for high speed file copies.

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## jserink

 *Mad Merlin wrote:*   

> FWIW, both the IDE and virtio drivers are strongly prefered to the SCSI drivers for emulated disks. The reason is that the SCSI implementation in KVM gets very little testing and love, so it's probably slower and buggier.
> 
> Also, you'll probably find that SMB is slower than FTP on real hardware too, SMB was never really designed for high speed file copies.

 

Hi Merlin:

an update....

turns out I'm using the old IDE driver which explains WHY I haven't experienced any more BSODs. It only BSOD'd when using the vertio disk driver, which, if you check the windows properties, says its scsi.

This uses the vertIO disk driver:

kvm -boot d -drive file=/home/jserink/VMs/Win_7_Pro.img,if=virtio,index=0,media=disk -drive file=/home/jserink/CDs/virtio-win-0.1-15.iso,if=ide,index=1,media=cdrom -drive file=/home/jserink/CDs/Win7X64.iso,if=ide,index=2,media=cdrom -m 4000 -smp 2 -usb -net nic,vlan=0,model=virtio,macaddr=52:54:00:00:EE:07 -net vde -localtime -no-quit -vga cirrus -name Win7 -monitor telnet:127.0.0.1:12997,server,nowait,ipv4 &

this changed it back to IDE:

kvm -boot c -hda /home/jserink/VMs/Win_7_Pro.img -cdrom /home/jserink/CDs/virtio-win-0.1-15.iso -m 4000 -smp 2 -usb -net nic,vlan=0,model=virtio,macaddr=52:54:00:00:EE:07 -net vde -localtime -no-quit -vga cirrus -name Win7 -monitor telnet:127.0.0.1:12997,server,nowait,ipv4 &

Cheers,

john

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