[Qemu-devel] live migration of 64-bit kvm guest (was: [BUG] Migration broken by "e1000: port to vmstate")

[Jan Kiszka]

Juan Quintela wrote:
> Jan Kiszka <address@hidden> wrote:
>> Juan Quintela wrote:
>>> Pierre Riteau <address@hidden> wrote:
>>>> e482dc3eaac43f88beea133843ae38c661262e97 breaks migration of a VM using an 
>>>> e1000 device (which is the default...).
>>>> Origin host is Debian Lenny 32-bits, destination host is Fedora 12 32-bit. 
>>>> Guest is running Debian Lenny 32-bit.
>>>> Symtoms: origin finishes migration correctly, but destination prints "load 
>>>> of migration failed" and the VM is stopped.
>>>>
>>>> This is because the origin closed the connexion, so qemu_fill_buffer reads 
>>>> a buffer with len == 0, which is treated as an error later (f->has_error = 
>>>> 1).
>>>> Reverting e482dc3eaac43f88beea133843ae38c661262e97 fixes the problem.
>>> Do you use --enable-kvm?  That could explain it.
>>>
>> Confirmed here - the hard way, ie. after debugging a while on my own
>> patches. My scenario is default command line + -enable-kvm, migration to
>> file (exec:cat), then restore from that file. Restore fails while
>> reading the e1000 state with EOF.
>>
>>> I will take at that two bugs this week.  I tested everything on 64bit
>>> hosts.
>> Any news on this?
> 
> nope, migration backwards took more time that I wanted.
> 
> Will take a look tomorrow.
> 

I'm currently pulling hair while trying to migrate a 64-bit x86 guest in
kvm mode (via exec+snapshot file, but without block migration and any of
my patches). The target crashes after taking over.

Are you aware of any 64-bit migration issues related to kvm (as you said
there are more bugs)? 32 bit works fine here.

Jan

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