Re: [Qemu-devel] [PATCH] [RFC] Add machine type pc-1.0-qemu-kvm for live migrate compatibility with qemu-kvm

[Alex Bligh]

On 4 Aug 2014, at 16:38, Serge Hallyn <address@hidden> wrote:

>> 
>> If you really want it to be called pc-1.0, you
>> can make it a machine property instead.
>> E.g. qemu-kvm-compatibility.
>> Teach management to set it if remote is qemu-kvm:
>>      -machine pc-1.0,qemu-kvm-compatibility=on
> 
> That sounds nice - Alex, what do you think?

Not having used the machine property stuff before,
or played with libvirt much, I'm not sure how this
helps libvirt.

I thought the issue here was that migrating from
1.0-qemu-kvm to 2.x OR 1.0-qemu-git to 2.x, libvirt
is going to to supply the same command line. As
libvirt doesn't know what the sender is (and
it's not possible to detect this automatically -
at least not without a far more intrusive patch),
one has to make a choice at build time as to what
'pc-1.0' represents. This is what patch #2 does.
I fully agree it is not pretty.

So I am not sure why
        -machine pc-1.0,qemu-kvm-compatibility=on
is any easier for libvirt than
        -machine pc-1.0-qemu-kvm

IE what does using a machine property rather than
a machine type buy us?

-- 
Alex Bligh