Re: [Qemu-devel] [PATCH v10-fix 15/18] Add the vhost-user netdev backend to the command line

[Eric Blake <eblake@redhat.com>]

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On 06/10/2014 04:02 AM, Nikolay Nikolaev wrote:
> The supplied chardev id will be inspected for supported options. Only
> a socket backend, with a set path (i.e. a Unix socket) and optionally
> the server parameter set, will be allowed. Other options (nowait, telnet)
> will make the chardev unusable and the netdev will not be initialised.
> 
> Additional checks for validity:
>   - requires `-numa node,memdev=..`
>   - requires `-device virtio-net-*`
> 
> The `vhostforce` option is used to force vhost-net when we deal with
> non-MSIX guests.

Here you call it vhostforce...[1]

>  
> +static int net_vhost_chardev_opts(const char *name, const char *value,
> +                                  void *opaque)
> +{
> +    VhostUserChardevProps *props = opaque;
> +
> +    if (strcmp(name, "backend") == 0 && strcmp(value, "socket") == 0) {
> +        props->is_socket = true;
> +    } else if (strcmp(name, "path") == 0) {
> +        props->is_unix = true;
> +    } else if (strcmp(name, "server") == 0) {
> +        props->is_server = true;
> +    } else {
> +        error_report("vhost-user does not support a chardev"
> +                     " with the following option:\n %s = %s",
> +                     name, value);
> +        props->has_unsupported = true;
> +        return -1;

Here you reported an error...[2]

> +    }
> +    return 0;
> +}
> +
> +static CharDriverState *net_vhost_parse_chardev(const NetdevVhostUserOptions *opts)
> +{
> +    CharDriverState *chr = qemu_chr_find(opts->chardev);
> +    VhostUserChardevProps props;
> +
> +    if (chr == NULL) {
> +        error_report("chardev \"%s\" not found", opts->chardev);
> +        return NULL;
> +    }
> +
> +    /* inspect chardev opts */
> +    memset(&props, 0, sizeof(props));
> +    qemu_opt_foreach(chr->opts, net_vhost_chardev_opts, &props, false);
> +
> +    if (!props.is_socket || !props.is_unix) {
> +        error_report("chardev \"%s\" is not a unix socket",
> +                     opts->chardev);
> +        return NULL;
> +    }
> +
> +    if (props.has_unsupported) {
> +        error_report("chardev \"%s\" has an unsupported option",
> +                opts->chardev);
> +        return NULL;

[2]...and again another error.  One report is sufficient.  For that
matter, I highly doubt you even need a has_unsupported member - since
you always error out early before allowing the device to be created, it
is just redundant information and will always be false for any device
that gets past creation without reporting an error.


> +##
> +{ 'type': 'NetdevVhostUserOptions',
> +  'data': {
> +    'chardev':        'str',
> +    '*vhost-force':    'bool' } }

[1]...and here you call it vhost-force...


> +Establish a vhost-user netdev, backed by a chardev @var{id}. The chardev should
> +be a unix domain socket backed one. The vhost-user uses a specifically defined
> +protocol to pass vhost ioctl replacement messages to an application on the other
> +end of the socket. On non-MSIX guests, the feature can be forced with
> +@var{vhostforce}.

[1]...yet document it as vhostforce.

If this has already been applied, then you need to submit a followup patch.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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