From: Marc Hartmayer <mhartmay@linux.ibm.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
Marc Hartmayer <mhartmay@linux.ibm.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>,
"Cornelia Huck" <cohuck@redhat.com>,
qemu-devel@nongnu.org,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Halil Pasic" <pasic@linux.ibm.com>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Marc-André Lureau" <marcandre.lureau@redhat.com>
Subject: Re: [PATCH 2/2] libvhost-user: handle endianness as mandated by the spec
Date: Mon, 03 Aug 2020 16:17:27 +0200 [thread overview]
Message-ID: <87wo2fhkzs.fsf@linux.ibm.com> (raw)
In-Reply-To: <20200802011240-mutt-send-email-mst@kernel.org>
On Sun, Aug 02, 2020 at 01:13 AM -0400, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Thu, Jul 30, 2020 at 04:07:31PM +0200, Marc Hartmayer wrote:
>> Since virtio existed even before it got standardized, the virtio
>> standard defines the following types of virtio devices:
>>
>> + legacy device (pre-virtio 1.0)
>> + non-legacy or VIRTIO 1.0 device
>> + transitional device (which can act both as legacy and non-legacy)
>>
>> Virtio 1.0 defines the fields of the virtqueues as little endian,
>> while legacy uses guest's native endian [1]. Currently libvhost-user
>> does not handle virtio endianness at all, i.e. it works only if the
>> native endianness matches with whatever is actually needed. That means
>> things break spectacularly on big-endian targets. Let us handle virtio
>> endianness for non-legacy as required by the virtio specification
>> [1]. The fencing of legacy virtio devices is done in
>> `vu_set_features_exec`.
>>
>> [1] https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-210003
>>
>> Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
>
>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Thanks.
[…snip]
--
Kind regards / Beste Grüße
Marc Hartmayer
IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Gregor Pillen
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294
next prev parent reply other threads:[~2020-08-03 14:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 14:07 [PATCH 0/2] Enable virtio-fs on s390x Marc Hartmayer
2020-07-30 14:07 ` [PATCH 1/2] virtio: add vhost-user-fs-ccw device Marc Hartmayer
2020-07-30 15:19 ` Cornelia Huck
2020-07-30 14:07 ` [PATCH 2/2] libvhost-user: handle endianness as mandated by the spec Marc Hartmayer
2020-08-02 5:13 ` Michael S. Tsirkin
2020-08-03 14:17 ` Marc Hartmayer [this message]
2020-08-03 9:26 ` Cornelia Huck
2020-08-21 8:50 ` Marc Hartmayer
2020-08-02 5:13 ` [PATCH 0/2] Enable virtio-fs on s390x Michael S. Tsirkin
2020-08-04 11:29 ` Dr. David Alan Gilbert
2020-08-27 12:19 ` Michael S. Tsirkin
2020-08-27 12:26 ` Cornelia Huck
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