qemu 0.10.0 - cd/dvd drive access problems

[Doug Barton]

On Mon, 9 Mar 2009, Juergen Lock wrote:

> In article <20090309103706.0a44fb26 at ernst.jennejohn.org> you write:
>> On Sun, 08 Mar 2009 18:00:25 -0700
>> Doug Barton <dougb at FreeBSD.org> wrote:
>>
>>> One of my main reasons for wanting to install qemu was to be able to
>>> use Windows tools for things like archiving DVDs. Now that I have qemu
>>> working pretty well for most things, I tried to start using it for
>>> DVD/CD access and it's not working well at all. I installed XP via a
>>> typical installation CD, so I thought I had it made in this area. :(
>>>
>>> I'm using '-cdrom /dev/acd0' the same way I did for the install. If
>>> there is a disc in the drive when I start qemu I can "see" the disc,
>>> and copy some small files from it. However trying to copy/read large
>>> files (say, 1G) doesn't work at all. I get an error saying that sector
>>> of the disc cannot be read (this is with known-good discs).
>
> Hmm.  I wonder if this bug is related to the opensuse installer segfault,

Not sure I follow you there, sorry.

> have you tried with the (now older, still at the 20080620 snapshot)
> qemu-devel port thats in the tree?

That's actually what I started with (i.e., I compiled that port and used 
it to install my windows guest) but I switched to the 0.10.0 before I 
started goofing around with the CD/DVD stuff. I'll try going back to the 
older version, but it's not likely I'll be able to get to it today.

> You could also try the new "werror"
> option for -drive (possible values are:
>    report    - report errors to a guest as IO errors
>    ignore    - continue as if nothing happened
>    stop      - stop VM on any error and retry last command on resume
>    enospc    - stop vm on ENOSPC error and retry last command on resume
>                all other errors are reported to a guest.
> I think the default is "enospc" in 0.10.0 .  Yeah -cdrom is readonly
> but who knows...)

Errrr, -cdrom being read-only is a problem, I need to be able to write CDs 
and DVDs. Is there way to do that with the -drive option? I looked at the 
man page but couldn't quite grasp it well enough to get a command line to 
try.

BTW, any hope that we'll have working USB in qemu on -current any time 
soon? I can't help thinking that some of these issues might be avoided if 
the windows guest could "see" my external drive directly. It would also 
allow me to give syncing my iPhone a try, which is another big motivator 
for me to be trying this at all.

> And finally you could try disabling aio (untested, I hope the following 
> still works:)

If I don't have any luck with the other options I'll give this a try as 
well, thanks.

> Actually qemu 0.10.0 (and also the last few snapshots I posted updates
> for) now does its own aio emulation using threads, so the aio(4) kld or
> kernel option is no longer needed.

Ah, interesting. I wonder if it's possible that the kernel module is 
interfering?


Doug

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