Re: [Qemu-devel] [Bug 818673] Re: virtio: trying to map MMIO memory

[hkran <hkran@vnet.linux.ibm.com>]

On 09/16/2011 03:37 AM, Rick Vernam wrote:
> On Thursday 15 September 2011 11:23:53 Rick Vernam wrote:
>> On Wednesday 14 September 2011 16:30:11 Rick Vernam wrote:
>>> On Wednesday 14 September 2011 14:42:09 vrozenfe wrote:
>>>> Thank you, Rick.
>>>>
>>>> Could you help me to narrow this problem down?
>>> Absolutely.
>>>
>>>> As I see, you have three virtio drivers installed on your system -
>>>> block, net, and virtio serial. Technically, anyone of them can create
>>>> "trying to map MMIO memory" problem. The best way to find a buggy
>>>> driver ( or drivers) will be to isolate one from the other. If you
>>>> can, please try running only one virtio device every time to see which
>>>> driver sends incorrect  scatter/gather list element to QEMU.
>>> Sure, no problem.  I'll have that in the next few days.
>> I started qemu without any of the virt-serial stuff, specfically:
>> qemu-system-x86_64 -cpu host -enable-kvm -pidfile
>> /home/rick/qemu/hds/wxp.pid - drive
>> file=/home/rick/qemu/hds/wxp.raw,if=virtio,aio=native -m 1536 -name WinXP
>> -net nic,model=virtio -net user -localtime -usb -vga qxl -spice
>> port=1234,disable-ticketing -monitor stdio
>>
>> It's been running for around 2 hours and no crash yet.
> So without virt-serial, the machine ran until I rebooted the guest OS, then
> crashed with the same error message.  Without virt-serial it seemed to be
> stable so long as it was just left running.
>
> Now I'll run it without virt-net, and let you know how that goes.
>
>> Thanks,
>> -Rick
>>
>>>> Another question. You said, the problem happens after every second or
>>>> third restart. Do you shutdown your VM,  or just restart it?
>>> Have to shut down the VM guest so that the qemu process exits.
>>>
>>>> How does it work
>>>> after going through several hibernate/resume, and/or suspend/resume
>>>> cycles.
>>> I often will suspend with or without pausing qemu (via monitor commands
>>> 'stop' and 'cont').  I have never experienced any problem with the qemu
>>> process that was running prior to the suspend.
>>>
>>>> Best regards,
>>>> Vadim.
>>> Thanks,
>>> -Rik
I have tried many times with many restarts or shutdown-and-boot xp guest 
but failed to meet the crashing.
(I am using the virtio drivers referenced in the earlier mail list.)
my command:

/home/huikai/qemu15/bin/qemu  --enable-kvm  -m 768  -drive 
file=/home/huikai/winxp_dev.img,if=virtio  -net nic,model=virtio -net 
user -usb -usbdevice tablet  -localtime -vga qxl -device virtio-serial 
-chardev spicevmc,name=vdagent,id=vdagent -device 
virtserialport,chardev=vdagent,name=spice0 -spice 
port=1234,disable-ticketing   -monitor telnet:localhost:12341,server,nowait