Re: [PATCH 8/8] virtio_ring.h: do not include <stdint.h> from exported header

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch <linux-arch@vger.kernel.org>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	virtualization list <virtualization@lists.linux-foundation.org>,
	Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 8/8] virtio_ring.h: do not include <stdint.h> from exported header
Date: Tue, 5 Apr 2022 07:57:21 -0400	[thread overview]
Message-ID: <20220405075627-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CAK8P3a0FjfSyUtv9a9dM7ixsK2oY9VF7WZPvDctn2JRi7A0YyQ@mail.gmail.com>

On Tue, Apr 05, 2022 at 08:29:36AM +0200, Arnd Bergmann wrote:
> On Tue, Apr 5, 2022 at 7:35 AM Christoph Hellwig <hch@infradead.org> wrote:
> >
> > On Mon, Apr 04, 2022 at 10:04:02AM +0200, Arnd Bergmann wrote:
> > > The header is shared between kernel and other projects using virtio, such as
> > > qemu and any boot loaders booting from virtio devices. It's not technically a
> > > /kernel/ ABI, but it is an ABI and for practical reasons the kernel version is
> > > maintained as the master copy if I understand it correctly.
> >
> > Besides that fact that as you correctly states these are not a UAPI at
> > all, qemu and bootloades are not specific to Linux and can't require a
> > specific kernel version.  So the same thing we do for file system
> > formats or network protocols applies here:  just copy the damn header.
> > And as stated above any reasonably portable userspace needs to have a
> > copy anyway.
> 
> I think the users all have their own copies, at least the ones I could
> find on codesearch.debian.org.

kvmtool does not seem to have its own copy, just grep vring_init.

> However, there are 27 virtio_*.h
> files in include/uapi/linux that probably should stay together for
> the purpose of defining the virtio protocol, and some others might
> be uapi relevant.
> 
> I see that at least include/uapi/linux/vhost.h has ioctl() definitions
> in it, and includes the virtio_ring.h header indirectly.
> 
> Adding the virtio maintainers to Cc to see if they can provide
> more background on this.
> 
> > If it is just as a "master copy" it can live in drivers/virtio/, just
> > like we do for other formats.
> 
> It has to be in include/linux/ at least because it's used by a number
> of drivers outside of drivers/virtio/.
> 
>         Arnd
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization
> 

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