Re: 32-bit binaries failing in 64 bit guests after using vmport

[Anthony Liguori <anthony@codemonkey.ws>]

Soren Hansen wrote:
> Esteemed kvm developers!
>
> I've been trying to debug this bug
>
>     https://bugs.launchpad.net/ubuntu/+source/kvm/+bug/219165
>
> It originally revealed itself by failing to run grub (which is a 32 bit
> binary) when installing Ubuntu from our live cd. It turned out to be a
> more general problem of 32 bit binaries failing to run. The server
> install worked like a charm. I eventually discovered that loading the
> vmmouse driver triggered it and narrowed it down to the call to
> kvm_load_registers in vmport_ioport_read. 
>
> We're releasing on Thursday, and I needed a quick fix, so I reverted the
> calls to kvm_{save,load}_registers in vmport_ioport_read to the old code
> that simply saved the eax, ebx, ecx, edx, esi, and edi registers, but
> I'm supposing kvm_{load,save}_registers really should work here.
>   

Ah, you may have missed the fix that updated the KVM load/save functions 
to deal with the in-kernel APIC.

It turns out, vmmouse was horribly broken with SMP guests too.  See

commit 9949bd84ac4dfdfc60b2974557819637b8719911
Author: Anthony Liguori <aliguori@us.ibm.com>
Date:   Thu Apr 3 18:37:16 2008 -0500

commit 5208ce19dca268f84a2b9441c2fbb6129161e44c
Author: Marcelo Tosatti <mtosatti@redhat.com>
Date:   Thu Apr 3 20:24:37 2008 -0300

commit 85a67aa2a1b942ddccfcbd625d280869367edc95
Author: Marcelo Tosatti <mtosatti@redhat.com>
Date:   Fri Apr 11 13:24:41 2008 -0300

Regards,

Anthony LIguori

> I dug a bit further into the code and tried disabling various pieces of
> the kvm_load_registers until it finally worked again. The problem seems
> to only arise when the lstar msr is loaded. I've looked at the code, but
> seeing as three days ago I didn't know there was such a thing as an
> lstar msr, I'm finding myself getting stuck. :)
>
> Any pointers in the right direction would be lovely.
>
>   
> ------------------------------------------------------------------------
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by the 2008 JavaOne(SM) Conference 
> Don't miss this year's exciting event. There's still time to save $100. 
> Use priority code J8TL2D2. 
> http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone
> ------------------------------------------------------------------------
>
> _______________________________________________
> kvm-devel mailing list
> kvm-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/kvm-devel
>   


-------------------------------------------------------------------------
This SF.net email is sponsored by the 2008 JavaOne(SM) Conference 
Don't miss this year's exciting event. There's still time to save $100. 
Use priority code J8TL2D2. 
http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone