[pve-devel] [PATCH qemu-server] add 'flags' property to cpu option

[Dietmar Maurer]

> +    flags => {
> +	description => "Override CPU flags. Currently only the 'pcid' flag is
> supported."
> +		     . " Use '+pcid' or '-pcid' to enable or disable."
> +		     . " This takes precedence over flags coming from the cpu type or
> changed implicitly via the OS type.",
> +	format_description => 'flaglist',
> +	type => 'string',
> +	pattern => '[+-]pcid',
> +	optional => 1,
> +	default => '',

Why do we need a default of '' ?