From: Pawel Moll <pawel.moll@arm.com>
To: Marc Zyngier <Marc.Zyngier@arm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
"Michael S. Tsirkin" <mst@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH] virtio-spec: Define virtio-mmio registers as LE
Date: Fri, 01 Mar 2013 10:50:05 +0000 [thread overview]
Message-ID: <1362135005.3052.26.camel@hornet> (raw)
In-Reply-To: <513085EA.8070007@arm.com>
On Fri, 2013-03-01 at 10:41 +0000, Marc Zyngier wrote:
> On 14/02/13 10:54, Pawel Moll wrote:
> > To solve the never-ending confusions between hosts and guests
> > of different endianess, define all virtio-mmio registers as LE.
> >
> > This change should be safe at this stage, because no known
> > working mixed-endian system exists so there is virtually no
> > risk of breaking compatibility.
> >
> > Signed-off-by: Pawel Moll <pawel.moll@arm.com>
>
> Shouldn't we exclude the config space? PCI defines it as guest-endian,
> and the above tends to indicate that it should be LE with MMIO.
The spec says: "Device-specific configuration space starts at an offset
0x100 and is accessed with byte alignment. Its meaning and size depends
on the device and the driver."
I would hope that "accessed with byte alignment" is enough of a clue in
this subject, but if you think otherwise I can add a sentence stating
this explicitly.
Having said that, Rusty was contemplating enforcing LE config space in
the new PCI layout...
Paweł
next prev parent reply other threads:[~2013-03-01 10:50 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-13 14:25 [RFC PATCH] virt_mmio: fix signature checking for BE guests Marc Zyngier
2013-02-13 15:08 ` Pawel Moll
2013-02-13 15:28 ` Marc Zyngier
2013-02-13 15:46 ` Pawel Moll
2013-02-13 16:40 ` Marc Zyngier
2013-02-13 16:53 ` Michael S. Tsirkin
2013-02-13 17:04 ` Marc Zyngier
2013-02-14 0:22 ` Rusty Russell
2013-02-14 10:54 ` [PATCH] virtio-spec: Define virtio-mmio registers as LE Pawel Moll
2013-02-15 3:57 ` Rusty Russell
2013-03-01 10:41 ` Marc Zyngier
2013-03-01 10:50 ` Pawel Moll [this message]
2013-03-01 11:21 ` Marc Zyngier
2013-03-01 12:37 ` Pawel Moll
2013-03-01 13:16 ` Marc Zyngier
2013-03-05 0:11 ` Rusty Russell
2013-03-06 15:10 ` Pawel Moll
2013-03-07 6:36 ` Rusty Russell
2013-02-15 0:07 ` [RFC PATCH] virt_mmio: fix signature checking for BE guests Benjamin Herrenschmidt
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