From: "Michael S. Tsirkin" <mst@redhat.com>
To: Marcel Apfelbaum <marcel@redhat.com>
Cc: James Hogan <james.hogan@imgtec.com>,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org
Subject: Re: [BUG] virtio-net linux driver fails to probe on MIPS Malta since 'hw/virtio-pci: fix virtio behaviour'
Date: Mon, 20 Mar 2017 17:43:00 +0200 [thread overview]
Message-ID: <20170320174101-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <6b3ec98b-55e2-ecc8-d962-dc9d13866319@redhat.com>
On Mon, Mar 20, 2017 at 05:21:22PM +0200, Marcel Apfelbaum wrote:
> On 03/17/2017 11:57 PM, James Hogan wrote:
> > Hi,
> >
> > I've bisected the following failure of the virtio_net linux v4.10 driver
> > to probe in QEMU v2.9.0-rc1 emulating a MIPS Malta machine:
> >
> > virtio_net virtio0: virtio: device uses modern interface but does not have VIRTIO_F_VERSION_1
> > virtio_net: probe of virtio0 failed with error -22
> >
> > To QEMU commit 9a4c0e220d8a ("hw/virtio-pci: fix virtio behaviour").
> >
> > It appears that adding ",disable-modern=on,disable-legacy=off" to the
> > virtio-net -device makes it work again.
> >
> > I presume this should really just work out of the box. Any ideas why it
> > isn't?
> >
>
> Hi,
>
>
> This is strange. This commit changes virtio devices from legacy to virtio "transitional".
> (your command line changes it to legacy)
> Linux 4.10 supports virtio modern/transitional (as far as I know) and on QEMU side
> there is nothing new.
>
> Michael, do you have any idea?
>
> Thanks,
> Marcel
My guess would be firmware mishandling 64 bit BARs - we saw such
a case on sparc previously. As a result you are probably reading
all zeroes from features register or something like that.
Marcel, could you send a patch making the bar 32 bit?
If that helps we know what the issue is.
> > Cheers
> > James
> >
next prev parent reply other threads:[~2017-03-20 15:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-17 21:57 [BUG] virtio-net linux driver fails to probe on MIPS Malta since 'hw/virtio-pci: fix virtio behaviour' James Hogan
2017-03-20 15:21 ` Marcel Apfelbaum
2017-03-20 15:43 ` Michael S. Tsirkin [this message]
2017-03-20 16:02 ` Marcel Apfelbaum
2017-03-21 14:16 ` Marcel Apfelbaum
2017-03-27 18:45 ` James Hogan
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