Xen devel - Apr 2006 - xen-unstable-9514 and CONFIG_IA32_EMULATION

Hi guys,

Maybe one of you quickly can tell me if the x86_64 kernel
configuration option CONFIG_IA32_EMULATION is supposed to work under
Xen?

I''ve used an ia32 root file system together with CONFIG_IA32_EMULATION
inside qemu-system-x86_64 for quite a while now (without xen). It
works pretty well.

However, when I try this with xen-unstable-9514 all I get is general
protection errors...

[snip]
NET: Registered protocol family 17
Sending DHCP requests ., OK
IP-Config: Got DHCP answer from 10.0.2.2, my address is 10.0.2.15
IP-Config: Complete:
      device=eth0, addr=10.0.2.15, mask=255.255.255.0, gw=10.0.2.2,
     host=10.0.2.15, domain=, nis-domain=(none),
     bootserver=10.0.2.2, rootserver=10.0.2.2, rootpathinit[1] general
protection rip:f7f3084b rsp:ffffc7ac error:802
init[1] general protection rip:f7f3084b rsp:ffff8300ffffc7ac error:802
init[1] general protection rip:f7f3084b rsp:ffff8300ffffc7ac error:802
...

Any thoughts?

Thanks,

/ magnus

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> Maybe one of you quickly can tell me if the x86_64 kernel 
> configuration option CONFIG_IA32_EMULATION is supposed to 
> work under Xen?
> 
> I''ve used an ia32 root file system together with 
> CONFIG_IA32_EMULATION inside qemu-system-x86_64 for quite a 
> while now (without xen). It works pretty well.
> 
> However, when I try this with xen-unstable-9514 all I get is 
> general protection errors...
It seems to work pretty well for me. What 32b distro are you using?
Does the system boot successfully despite the complaints? 

Ian
 
> [snip]
> NET: Registered protocol family 17
> Sending DHCP requests ., OK
> IP-Config: Got DHCP answer from 10.0.2.2, my address is 10.0.2.15
> IP-Config: Complete:
>       device=eth0, addr=10.0.2.15, mask=255.255.255.0, gw=10.0.2.2,
>      host=10.0.2.15, domain=, nis-domain=(none),
>      bootserver=10.0.2.2, rootserver=10.0.2.2, rootpath= 
> init[1] general protection rip:f7f3084b rsp:ffffc7ac 
> error:802 init[1] general protection rip:f7f3084b 
> rsp:ffff8300ffffc7ac error:802 init[1] general protection 
> rip:f7f3084b rsp:ffff8300ffffc7ac error:802 ...
> 
> Any thoughts?
> 
> Thanks,
> 
> / magnus
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
> 
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On 4/19/06, Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
wrote:
> > Maybe one of you quickly can tell me if the x86_64 kernel
> > configuration option CONFIG_IA32_EMULATION is supposed to
> > work under Xen?
> >
> > I''ve used an ia32 root file system together with
> > CONFIG_IA32_EMULATION inside qemu-system-x86_64 for quite a
> > while now (without xen). It works pretty well.
> >
> > However, when I try this with xen-unstable-9514 all I get is
> > general protection errors...
>
> It seems to work pretty well for me. What 32b distro are you using?
I''m using a minimal custom initramfs, basically busybox built using
crosstool.
> Does the system boot successfully despite the complaints?
Nope. I will get an endless amount of segfault messages, but no shell.

I did some more testing this morning. First I replaced /init with a
native static x86_64 version of bash. /init started ok, but running
the ia32 version of /bin/sh resulted in:

[snip]
NET: Registered protocol family 17
Sending DHCP requests ., OK
IP-Config: Got DHCP answer from 10.0.2.2, my address is 10.0.2.15
IP-Config: Complete:
      device=eth0, addr=10.0.2.15, mask=255.255.255.0, gw=10.0.2.2,
     host=10.0.2.15, domain=, nis-domain=(none),
     bootserver=10.0.2.2, rootserver=10.0.2.2, rootpathinit-3.1# /bin/sh
sh[13] general protection rip:f7fd684b rsp:ffffd1fc error:802
Segmentation fault
init-3.1#

To understand more I''ve tried the same initramfs with and without Xen,
on both i386 and x86_64.

Working in qemu (i386): vanilla-2.6.16, linux-2.6.16-xen (dom0)
Working in qemu-system-x86_64: vanilla-2.6.16
Not working in qemu-system-x8x_64: linux-2.6.16-xen (dom0)

I will try to find some real x86_64 hardware, but it the meantime I''d
be happy to email the initramfs to anyone. The file is about 2 megs
large.

Also, I''ve wonder if this is related to tls? Or maybe it is qemu...

Thanks for the help!

/ magnus

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On 4/20/06, Magnus Damm <magnus.damm@gmail.com>
wrote:
> I will try to find some real x86_64 hardware, but it the meantime
I''d
> be happy to email the initramfs to anyone. The file is about 2 megs
> large.
>
> Also, I''ve wonder if this is related to tls? Or maybe it is
qemu...
I''ve tried the initramfs on real x86_64 hardware with Xen, and it
seems to work correctly. So it looks like I''ve been running into some
qemu problem, sorry for the noise.

Thanks,

/ magnus

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