[libvirt] [PATCH 4/6] Canonicalize qemu machine types

[Daniel Veillard]

On Thu, Jul 23, 2009 at 06:34:42PM +0100, Mark McLoughlin wrote:
> In qemu-0.11 there is a 'pc-0.10' machine type which allows you to run
> guests with a machine which is compatible with the pc machine in
> qemu-0.10 - e.g. using the original PCI class for virtio-blk and
> virtio-console and disabling MSI support in virtio-net. The idea here
> is that we don't want to suprise guests by changing the hardware when
> qemu is updated.
> 
> I've just posted some patches for qemu-0.11 which allows libvirt to
> canonicalize the 'pc' machine alias to the latest machine version.
> 
> This patches makes us use that so that when a guest is configured to
> use the 'pc' machine type, we resolve that to 'pc-0.11' machine and
> save that in the guest XML.
> 
> See also:
> 
>   https://fedoraproject.org/wiki/Features/KVM_Stable_Guest_ABI
> 
> * src/qemu_conf.c: add qemudCanonicalizeMachine() to canonicalize
>   the machine type according to the machine aliases in capabilities
> 
[...]
>  /* Format is:
> - * <machine> <desc> [(default)]
> + * <machine> <desc> [(default)|(alias of <canonical>)]
>   */
>  static int
>  qemudParseMachineTypesStr(const char *output,
> @@ -319,6 +319,15 @@ qemudParseMachineTypesStr(const char *output,
>              list[0] = machine;
>              nitems++;
>          }
> +
> +        if ((t = strstr(p, "(alias of ")) && (!next || t < next)) {
> +            p = t + strlen("(alias of ");
> +            if (!(t = strchr(p, ')')) || (next && t >= next))
> +                continue;
> +
> +            if (!(machine->canonical = strndup(p, t - p)))
> +                goto error;
> +        }
>      } while ((p = next));

  hum, if you get (alias of  foo ) your canonical will end up being
" foo " instead of "foo" maybe spaces should be stripped before and
after the name (i.e. it would have been perfect in an XML attribute but
well ...)

[...]
> +static int
> +qemudCanonicalizeMachineFromInfo(virDomainDefPtr def,
> +                                 virCapsGuestDomainInfoPtr info,
> +                                 char **canonical)
> +{
> +    int i;
> +
> +    *canonical = NULL;
> +
> +    for (i = 0; i < info->nmachines; i++) {
> +        virCapsGuestMachinePtr machine = info->machines[i];
> +
> +        if (!machine->canonical)
> +            continue;
> +
> +        if (strcmp(def->os.machine, machine->name) != 0)
> +            continue;
> +
> +        if (!(*canonical = strdup(machine->canonical)))

  virReportOOMError(NULL) please :-)

> +            return -1;
> +
> +        break;

  ACK

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel at veillard.com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/