[Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[Thomas Munn]

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I would suggest that the documentation perhaps have large letters so people won't have to go through the hell that I did.  Basically, the "qemu-fast" patch is only for oses inside of the main os (I know it says it "guest" in docs), and NOT to be applied to main os!  You might want to include a warning so other people who aren't developers won't try applying this patch to their main kernel.  So Perhaps:
 
Warning:  The qemu-fast patch should NOT be applied to the "host" os, (e.g. the main os) as it will impair the functionality of qemu by causing segfaults and all kinds of other nasty stuff.  Only apply this when using linux inside of qemu-fast.  
 
You also might want to further clarify the purposes of qemu-fast and its ilk, when not to use etc.
 
Just my 2¢ worth.
 
Thomas


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Re: [Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[David]

Speaking of adding things to the documentation, it would be helpful to mention 
that Qemu *requires* a network connection (or a simulated one via 
'--dummy-net').

I ran into this problem because I still used dialup. I couldn't find any 
explanation for the error message I was getting in the documentation, or via 
Google. However, the act of going online caused Qemu to start  working, and 
it finally dawned on me what the problem was...

Thanks!

-- David Cuny

Re: [Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[Jim C. Brown]

On Wed, Jun 23, 2004 at 08:05:16AM -0400, David wrote:
> Speaking of adding things to the documentation, it would be helpful to mention 
> that Qemu *requires* a network connection (or a simulated one via 
> '--dummy-net').
> 
> I ran into this problem because I still used dialup. I couldn't find any 
> explanation for the error message I was getting in the documentation, or via 
> Google. However, the act of going online caused Qemu to start  working, and 
> it finally dawned on me what the problem was...
> 
> Thanks!
> 
> -- David Cuny
> 

That is not exactly true. Qemu works fine for me, even when I start it when I
am offline. However I use VDE/tuntap and do have a local area network, so
it is possible that qemu requires a network connection to function correctly
(IIRC since 0.5.5 qemu uses -user-net by default if it can not access tuntap,
and -dummy-net by default for earlier versions). Of course tuntap requires that
you have an actual ethernet card to work....

BTW if you are using the Windows port, you might be better off using -dummy-net
or -user-net ... I vaguely recall that one of the reasons -user-net was
introduced was because it was so hard to set up networking with qemu when
Windows was the host OS.

> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.

Re: [Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[John R. Hogerhuis]

On Wed, 2004-06-23 at 09:50, Jim C. Brown wrote:
> BTW if you are using the Windows port, you might be better off using -dummy-net
> or -user-net ... I vaguely recall that one of the reasons -user-net was
> introduced was because it was so hard to set up networking with qemu when
> Windows was the host OS.
> 
> > 
> > _______________________________________________
> > Qemu-devel mailing list
> > Qemu-devel@nongnu.org
> > http://lists.nongnu.org/mailman/listinfo/qemu-devel

The main reasons for -user-net are
to:

1) Create no-configuration-required networking. Any guest OS which is
set up to collect IP via DHCP should automatically have access to the
network when run under QEMU (assuming the host has network access).

2) Not require any changes to OS which necessitate root access. Many
users on Windows are not admin on their own machines, due to corporate
network policies.

One of these days we will see a autorun QEMU included on Knoppix disk
which will load up Knoppix on insertion into any Windows PC.

Re: [Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[Jean-Michel POURE]

Le mercredi 23 Juin 2004 18:50, Jim C. Brown a écrit :
> That is not exactly true. Qemu works fine for me, even when I start it when
> I am offline. However I use VDE/tuntap and do have a local area network, so
> it is possible that qemu requires a network connection to function
> correctly (IIRC since 0.5.5 qemu uses -user-net by default if it can not
> access tuntap, and -dummy-net by default for earlier versions). Of course
> tuntap requires that you have an actual ethernet card to work....
>
> BTW if you are using the Windows port, you might be better off using
> -dummy-net or -user-net ... I vaguely recall that one of the reasons
> -user-net was introduced was because it was so hard to set up networking
> with qemu when Windows was the host OS.

Can anyone confirm the same problems with -user-net as described here:

https://savannah.nongnu.org/bugs/?func=detailitem&item_id=9388
http://www.poure.com/screenshots/qemu_temp_6.png

A Debian SID guest with user-net seems to loose network packets. On the 
contrary, Tun networking works fine. Please note that this is not qemu-fast 
but qemu system emulator.

Cheers,
Jean-Michel

Re: [Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[Christof Petig]

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Jean-Michel POURE schrieb:
| Le mercredi 23 Juin 2004 18:50, Jim C. Brown a écrit :
|
|>That is not exactly true. Qemu works fine for me, even when I start it
when
|>I am offline. However I use VDE/tuntap and do have a local area
network, so
|>it is possible that qemu requires a network connection to function
|>correctly (IIRC since 0.5.5 qemu uses -user-net by default if it can not
|>access tuntap, and -dummy-net by default for earlier versions). Of course
|>tuntap requires that you have an actual ethernet card to work....
|>
|>BTW if you are using the Windows port, you might be better off using
|>-dummy-net or -user-net ... I vaguely recall that one of the reasons
|>-user-net was introduced was because it was so hard to set up networking
|>with qemu when Windows was the host OS.
|
|
| Can anyone confirm the same problems with -user-net as described here:

I can confirm a different problem with -user-net:

I only once got a working ftp connection between the guest (win95) and
the host (debian sid/powerpc). This happened when I debugged the
ethernet card (DEBUG_NE2000) [perhaps I set -O0 -g]. I was unable to
repeat this success so far. [Will try again with -O0 -g]

Given the reports about slirp miscompiling with -O2 (or without
- -fno-strict-aliasing) I would look there for the guilt. [I looked there
and turned my eyes away quickly]

~   Christof
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Re: [Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[John R. Hogerhuis]

Try entering PASSIVE before attempting your transfer

-- John.

On Thu, 2004-06-24 at 02:08, Christof Petig wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Jean-Michel POURE schrieb:
> | Le mercredi 23 Juin 2004 18:50, Jim C. Brown a écrit :
> |
> |>That is not exactly true. Qemu works fine for me, even when I start it
> when
> |>I am offline. However I use VDE/tuntap and do have a local area
> network, so
> |>it is possible that qemu requires a network connection to function
> |>correctly (IIRC since 0.5.5 qemu uses -user-net by default if it can not
> |>access tuntap, and -dummy-net by default for earlier versions). Of course
> |>tuntap requires that you have an actual ethernet card to work....
> |>
> |>BTW if you are using the Windows port, you might be better off using
> |>-dummy-net or -user-net ... I vaguely recall that one of the reasons
> |>-user-net was introduced was because it was so hard to set up networking
> |>with qemu when Windows was the host OS.
> |
> |
> | Can anyone confirm the same problems with -user-net as described here:
> 
> I can confirm a different problem with -user-net:
> 
> I only once got a working ftp connection between the guest (win95) and
> the host (debian sid/powerpc). This happened when I debugged the
> ethernet card (DEBUG_NE2000) [perhaps I set -O0 -g]. I was unable to
> repeat this success so far. [Will try again with -O0 -g]
> 
> Given the reports about slirp miscompiling with -O2 (or without
> - -fno-strict-aliasing) I would look there for the guilt. [I looked there
> and turned my eyes away quickly]
> 
> ~   Christof
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.2.4 (GNU/Linux)
> Comment: Using GnuPG with Debian - http://enigmail.mozdev.org
> 
> iD8DBQFA2poEng+R+0ucfO0RAl4XAJ0bkZ9IHXhszOcbEqjjalatRrHWDwCggRw2
> va6e6cMWeDTQWBynwCQOxG8=
> =Z7ux
> -----END PGP SIGNATURE-----
> 
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
> 
> 

Re: [Qemu-devel] Clarification about qemu-fast (was segfaults in fc1)

[Antony T Curtis]

On Wed, 2004-06-23 at 14:03, Thomas Munn wrote:
> I would suggest that the documentation perhaps have large letters so
> people won't have to go through the hell that I did.  Basically, the
> "qemu-fast" patch is only for oses inside of the main os (I know it
> says it "guest" in docs), and NOT to be applied to main os!  You might
> want to include a warning so other people who aren't developers won't
> try applying this patch to their main kernel.  So Perhaps:
>  
> Warning:  The qemu-fast patch should NOT be applied to the "host" os,
> (e.g. the main os) as it will impair the functionality of qemu by
> causing segfaults and all kinds of other nasty stuff.  Only apply this
> when using linux inside of qemu-fast.  
>  
> You also might want to further clarify the purposes of qemu-fast and
> its ilk, when not to use etc.

I have patched it to compile under FreeBSD... but I do not know how I
should test/debug it ...
-- 
Antony T Curtis <antony.t.curtis@ntlworld.com>