Re: [Qemu-devel] qemu/qemu-kvm floppy regression brought by 212ec7baa28cc9d819234fed1541fc1423cfe3d8

[Zhi Yong Wu]

On Fri, Oct 28, 2011 at 7:46 PM, Lucas Meneghel Rodrigues
<address@hidden> wrote:
> On 10/27/2011 11:17 PM, Zhi Yong Wu wrote:
>>
>> On Fri, Oct 28, 2011 at 2:57 AM, Lucas Meneghel Rodrigues
>> <address@hidden>  wrote:
>>>
>>> On 10/27/2011 05:17 AM, Stefan Hajnoczi wrote:
>>>>
>>>> On Wed, Oct 26, 2011 at 03:19:17PM -0200, Lucas Meneghel Rodrigues
>>>> wrote:
>>>>>
>>>>> On 10/26/2011 01:47 PM, Kevin Wolf wrote:
>>>>>>
>>>>>> Am 26.10.2011 16:41, schrieb Lucas Meneghel Rodrigues:
>>>>>>>
>>>>>>> Hi folks:
>>>>>>>
>>>>>>> We've captured a regression with floppy disk on recent qemu (and
>>>>>>> qemu-kvm, after a code merge). We bisected it to be caused by:
>>>>>>>
>>>>>>> commit 212ec7baa28cc9d819234fed1541fc1423cfe3d8
>>>>>>> Author: Richard Henderson<address@hidden>
>>>>>>> Date:   Mon Aug 15 15:08:45 2011 -0700
>>>>>>>
>>>>>>>      fdc: Convert to isa_register_portio_list
>>>>>>>
>>>>>>>      Signed-off-by: Richard Henderson<address@hidden>
>>>>>>>      Signed-off-by: Avi Kivity<address@hidden>
>>>>>>>
>>>>>>> Since this commit, the guest doesn't see a floppy disk attached to it
>>>>>>> anymore, blocking kvm autotest ability to install windows guests
>>>>>>> automatically. This is a big deal for kvm autotest (ruins our
>>>>>>> automated
>>>>>>> regression jobs), so please take a look at it.
>>>>>>
>>>>>> Can you please try again with the latest block branch? I think there
>>>>>> is
>>>>>> a patch queued that will fix it.
>>>>>
>>>>> Kevin, I did try with HEAD of your repo:
>>>>>
>>>>> git://repo.or.cz/qemu/kevin.git
>>>>>
>>>>> address@hidden qemu-kwolf]$ git branch -r
>>>>>   origin/HEAD ->    origin/master
>>>>>   origin/blkqueue
>>>>>   origin/blkqueue-v1
>>>>>   origin/block
>>>>>   origin/coroutine
>>>>>   origin/coroutine-block
>>>>>   origin/coroutine-devel
>>>>>   origin/devel
>>>>>   origin/ehci
>>>>>   origin/for-anthony
>>>>>   origin/for-stable-0.14
>>>>>   origin/inplace-conversion
>>>>>   origin/master
>>>>>
>>>>> With this repo, master branch, the problem persists. With the block
>>>>> branch, the problem persists.
>>>>>
>>>>> Now, with the blkqueue branch the problem is resolved. Cleber had
>>>>> the same results booting a FreeDOS floppy. So the fix is indeed in
>>>>> blkqueue.
>>>>>
>>>>> Oh, you might want to check the blkqueue branch, it does have quite
>>>>> a bunch of set but unused variables, which will cause compilation
>>>>> errors unless --disable-werror is passed to the configure script.
>>>>
>>>> I think blkqueue is an older development branch of the "block queue"
>>>> feature that Kevin was working on.  It is not Kevin's block tree (see
>>>> his "block" branch).
>>>
>>> So no, the block branch does not resolve the floppy access problem.
>>>
>>> Well, considering the tests of the stable set I'm running against qemu
>>> right
>>> now, this is not the biggest of our problems... I'm verifying qemu is
>>> segfaulting on nearly every prolonged attempt of doing migration... I'm
>>> about to write an email about it.
>>
>> What is the OS of your guest? fedora16 or RHEL6? I would like recently
>> to use floppy device in guest.
>
> Ok, correcting my answer, it was Windows 7 SP1. For some reason, I read
> 'host' instead of guest. I had a long day when I wrote the 1st reply.
>
> It's been a while that we've verified that the linux floppy driver is quite
> unstable. In general linux + floppy devices on a guest tends to crash the
> guest kernel, and that's why in kvm autotest we moved from floppy devices to
> cdroms to hold the kickstart file. The fact you managed to get things
> working under F14 means you are lucky, and that particular floppy driver bug
> does not happen under F14's kernel. We never had such a kernel crash problem
> with any of the Windows's kernels.
>
> So if I were you, I would *not* use a floppy with a linux guest. Well,
> unless you want to debug the floppy driver bug and fix this on upstream
> linux once for all, so future versions of linux won't have this problem.
I need to do some works for fdc, etc. So i have to use it in one
linux guest. anyway, thanks.

>



-- 
Regards,

Zhi Yong Wu