Re: [Qemu-devel] [RFC PATCH v5 4/6] module: implement module loading function

[Alex Bligh]

--On 11 September 2013 13:38:27 +0800 Fam Zheng <address@hidden> wrote:

> +    switch (type) {
> +    case MODULE_LOAD_BLOCK:
> +        path = CONFIG_PREFIX "/qemu/block/";
> +        break;
> +    case MODULE_LOAD_UI:
> +        path = CONFIG_PREFIX "/qemu/ui/";
> +        break;
> +    case MODULE_LOAD_NET:
> +        path = CONFIG_PREFIX "/qemu/net/";
> +        break;
> +    default:
> +        return;
> +    }
> +

I appreciate I am coming in late into this discussion, and am only scanning
the code quickly, so apologies if I have the wrong end of the stick.

This APPEARS to load modules from
a) a fixed path determined at compile time
b) a path which is not dependent on qemu version

This would make it hard to have 2 versions of qemu installed on a
system at once, or even develop one version of qemu with another
version installed. I suspect this will be hard not only for developers,
but also for distributions, particularly if the idea is to keep vms
running during upgrades. Consider the case where packages A and B
both depend on qemu module package C, then you wish to upgrade to
A', B' and C'. At some point you are likely to want both C and C'
installed. Is the idea here that QEMU is always built with CONFIG_PREFIX
having versioning inside it (in a distro environment)?

Can I suggest that at the very least, it should be possible to specify
an alternate path to the module directory via the CLI?

--
Alex Bligh