Re: [Qemu-devel] [RFC PATCH] vmstate: Enable custom migration block name check

[Alexander Graf]

On 25.08.14 12:22, Alexey Kardashevskiy wrote:
> This adds a callback to support custom names for migration blocks.
> 
> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> ---
> 
> RFC! not a real patch!
> 
> There was a problem a while ago how to migrate sPAPR TCE tables - they
> needed unique id + instance_id and there 2 approaches for that:
> 
> 1. Put them on a virtual made-up TCE bus, LIOBN (logical bus number) is
> an unique ID and this would give TCE tables unique names like
> address@hidden/spapr_iommu, instance id would always be 0.
> 
> vmstate_spapr_tce_table would be registered via DeviceClass::vmsd pointer.
> 
> 2. Do not register vmsd via DeviceClass and use explicit call of
> vmstate_register() using LIOBN as an instance id. This way TCE tables would
> get "spapr_iommu" name and unique id == LIOBN.
> 
> Approach 2 is used by upstream.
> 
> Both 1 and 2 were suggested by maintainers :) However with 1 month delay
> and I started using 1) in our internal build of "powerkvm".
> 
> In the current version of our internal "powerkvm" thing I used 2) as this
> is what upstream uses.
> 
> 
> The proposed patch is a part of a hack to allow migration
> address@hidden/spapr_iommu + 0  to   spapr_iommu + 80000000.
> 
> 
> Is this too horrible to be considered as a patch for upstream?

Is there any reason you can't keep this patch in your downstream fork
along with the user of it? :)


Alex