Re: Device pass-through

[Gordon Messmer <yinyang@eburg.com>]

On 01/06/2012 01:31 AM, André Weidemann wrote:
> On 06.01.2012 08:25, Gordon Messmer wrote:
>> Well, I finally figured out that I have to enable the reading of roms
>> from the device by writing "1" to the "rom" node in /sys/. Now the
>> problem is that the rom is 64k, and only 32k are making it into the
>> guest. I saw a reference to this problem here:
>
> Do you have the ROM as a file on your HDD perhaps? If so, you can try
> the following: -device pci-assign,host=05:00.0,romfile=${ROMFILE}.
> This used to work fine for me even with ROM file of around 130k.

I do, and I'm actually using that.  I'm using a shell script wrapper to 
"fix" the argument for the PCI video card, since libvirt XML doesn't 
seem to provide an option for rom files.  The command that gets run is 
included below.

I've learned that I was actually incorrect about the problem.  The card 
in the guest *does* have a 32K rom, but it's not a truncated version of 
the ATI rom.  Instead, it's the "Plex86/Bochs VGABios (PCI)."  I've 
tried starting the guest with no graphics or video hardware specified in 
the libvirt XML, but qemu-kvm just eats a bunch of CPU time.  I don't 
see any serial console output (I do see grub and kernel output on the 
serial console when I have virtual video hardware specified), so I'm 
pretty sure the guest isn't actually starting.



/usr/libexec/qemu-kvm -S -M rhel6.2.0 -enable-kvm -m 4096 -smp 
4,sockets=4,cores=1,threads=1 -name herald -uuid 
556638be-ee50-e2f6-1d22-37b98b63b8d1 -nodefconfig -nodefaults -chardev 
socket,id=charmonitor,path=/var/lib/libvirt/qemu/herald.monitor,server,nowait 
-mon chardev=charmonitor,id=monitor,mode=readline -rtc base=utc -drive 
file=/dev/mapper/VolGroup-lv_vm_herald,if=none,id=drive-virtio-disk0,format=raw,cache=none,aio=native 
-device 
virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 
-device 
virtio-net-pci,vlan=0,id=net0,mac=52:54:00:21:e7:9e,bus=pci.0,addr=0x3 
-net tap,fd=25,vlan=0,name=hostnet0 -chardev pty,id=charserial0 -device 
isa-serial,chardev=charserial0,id=serial0 -usb -device 
usb-tablet,id=input0 -vnc 127.0.0.1:0 -vga cirrus -device 
pci-assign,host=00:14.2,id=hostdev0,configfd=26,bus=pci.0,addr=0x5 
-device 
pci-assign,host=05:00.0,id=hostdev1,configfd=27,bus=pci.0,addr=0x7,romfile=/var/lib/libvirt/images/Radeon3470.rom 
-device usb-host,hostbus=5,hostaddr=3,id=hostdev2 -device 
usb-host,hostbus=7,hostaddr=3,id=hostdev3 -device 
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6