Re: [RFC PATCH 1/7] hw/mem: Add tagged memory backend object

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Thu, 27 Nov 2025 22:55:19 +0000
Alireza Sanaee <alireza.sanaee@huawei.com> wrote:

> Add a new memory-backend-tagged supports a tag property where you can
> find it based on tag. This is useful for scenarios where you want to add
> a piece of memory for a particular purpose to be passed for another
> device.
> 
> At the moment, this only supports a ram-backed object where we add a tag
> to it, and it temporary. However, we are planning for a generalized
> approach. The plan is to have a shim object where we add a tag to it,
> and then it can be later linked to any BACKEND object types.
> 
> Example use QMP API:
> {
> 
>     "execute": "object-add",
>     "arguments": {
>         "qom-type": "memory-backend-tagged",
>         "id": "tm0",
>         "size": 1073741824,
>         "tag": "6be13bce-ae34-4a77-b6c3-16df975fcf1a"
>     }
> }
> 
> Tags are assumed to be UUID. But this is something for debate maybe.
> 
> Signed-off-by: Alireza Sanaee <alireza.sanaee@huawei.com>
Just to keep a note here on what we discussed offline

Given this doesn't end up with a shim, but rather would need a
variant for each potential backend type, I'd not do this and instead
(For now) anyway, just add tag as a property to the HostMemoryBackend

We can come up with a clever solution later if that isn't an acceptable
path forwards.

Jonathan