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Date:   Tue, 7 Sep 2021 17:49:21 -0700 (PDT)
From:   Stefano Stabellini <sstabellini@kernel.org>
To:     Jan Beulich <jbeulich@suse.com>
cc:     Juergen Gross <jgross@suse.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH] xen/pvcalls: backend can be a module
In-Reply-To: <54a6070c-92bb-36a3-2fc0-de9ccca438c5@suse.com>
Message-ID: <alpine.DEB.2.21.2109071745270.14059@sstabellini-ThinkPad-T480s>
References: <54a6070c-92bb-36a3-2fc0-de9ccca438c5@suse.com>
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On Tue, 7 Sep 2021, Jan Beulich wrote:
> It's not clear to me why only the frontend has been tristate. Switch the
> backend to be, too.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Actually although the frontend is a tristate, it cannot really work as a
module. Specifically see pvcalls_stream_ops in the enabling patch (still
not upstream):

https://github.com/lf-edge/runx/blob/master/kernel/patches/0001-patch-pvcalls_enable.patch


So I had to change tristate to bool for XEN_PVCALLS_FRONTEND in our
internal kernel tree.

That said, the PVCalls backend could very well be a module and
technically I don't see any reasons why not. So:


Acked-by: Stefano Stabellini <sstabellini@kernel.org>


> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -214,7 +214,7 @@ config XEN_PVCALLS_FRONTEND
>  	  implements them.
>  
>  config XEN_PVCALLS_BACKEND
> -	bool "XEN PV Calls backend driver"
> +	tristate "XEN PV Calls backend driver"
>  	depends on INET && XEN && XEN_BACKEND
>  	help
>  	  Experimental backend for the Xen PV Calls protocol
>