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Date:   Tue, 7 Sep 2021 10:30:17 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Jan Beulich <jbeulich@suse.com>
Cc:     Bjorn Helgaas <bhelgaas@google.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
        Juergen Gross <jgross@suse.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: [PATCH 10/12] xen-pcifront: this module is PV-only
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Update subject to follow conventions (use "git log --oneline
drivers/pci/Kconfig").  Should say what this patch does.

Commit log below should also say what this patch does.  Currently it's
part of the rationale for the change, but doesn't say what the patch
does.

On Tue, Sep 07, 2021 at 02:10:41PM +0200, Jan Beulich wrote:
> It's module init function does a xen_pv_domain() check first thing.
> Hence there's no point building it in non-PV configurations.

s/It's/<name of function that calls xen_pv_domain()/   # pcifront_init()?
s/building it/building <name of module>/               # xen-pcifront.o?

I see that CONFIG_XEN_PV is only mentioned in arch/x86, so
CONFIG_XEN_PV=y cannot be set on other arches.  Is the current
"depends on X86" just a reflection of that, or is it because of some
other x86 dependency in the code?

The connection between xen_pv_domain() and CONFIG_XEN_PV is not
completely obvious.

If you only build xen-pcifront.o when CONFIG_XEN_PV=y, and
xen_pv_domain() is true if and only if CONFIG_XEN_PV=y, why bother
calling xen_pv_domain() at all?

> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -110,7 +110,7 @@ config PCI_PF_STUB
>  
>  config XEN_PCIDEV_FRONTEND
>  	tristate "Xen PCI Frontend"
> -	depends on X86 && XEN
> +	depends on XEN_PV
>  	select PCI_XEN
>  	select XEN_XENBUS_FRONTEND
>  	default y
>