[libvirt] [PATCH] virsh: use virConnectGetDomainCapabilities with maxvcpus

[Peter Krempa]

On Wed, Jul 27, 2016 at 18:08:29 +0530, Shivaprasad G Bhat wrote:
> virsh maxvcpus --type kvm output is useless on PPC. Also, in
> commit e6806d79 we documented not rely on virConnectGetMaxVcpus
> output. Fix the  maxvcpus to use virConnectGetDomainCapabilities
> now to make it useful. The call is made to use the default qemu
> binary and to check for the host machine and arch which is what the
> command intends to do anyway.
> 
> Signed-off-by: Shivaprasad G Bhat <sbhat at linux.vnet.ibm.com>
> ---
>  tools/virsh-host.c |   33 +++++++++++++++++++++++++++++----
>  1 file changed, 29 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/virsh-host.c b/tools/virsh-host.c
> index 57f0c0e..cf001c6 100644
> --- a/tools/virsh-host.c
> +++ b/tools/virsh-host.c
> @@ -606,18 +606,43 @@ static bool
>  cmdMaxvcpus(vshControl *ctl, const vshCmd *cmd)
>  {
>      const char *type = NULL;
> -    int vcpus;
> +    unsigned int vcpus;
> +    char *caps = NULL;
> +    const unsigned int flags = 0; /* No flags so far */
> +    xmlDocPtr xml = NULL;
> +    xmlXPathContextPtr ctxt = NULL;
> +    bool ret = false;
>      virshControlPtr priv = ctl->privData;
>  
>      if (vshCommandOptStringReq(ctl, cmd, "type", &type) < 0)
>          return false;
>  
> -    if ((vcpus = virConnectGetMaxVcpus(priv->conn, type)) < 0)
> -        return false;
> +    caps = virConnectGetDomainCapabilities(priv->conn, NULL, NULL, NULL, type, flags);
> +    if (!caps) {
> +        vshError(ctl, "%s", _("failed to get domain capabilities"));
> +        goto cleanup;
> +    }

This will break compatibility when connecting to older versions of the
daemon which don't support the virConnectGetDomainCapabilities.

Peter