From: "Michael S. Tsirkin" <mst@redhat.com>
To: "Richard W.M. Jones" <rjones@redhat.com>
Cc: jejb@linux.vnet.ibm.com, martin.petersen@oracle.com,
jasowang@redhat.com, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, hch@lst.de,
pbonzini@redhat.com
Subject: Re: [PATCH 1/2] virtio: Reduce BUG if total_sg > virtqueue size to WARN.
Date: Fri, 11 Aug 2017 00:41:47 +0300 [thread overview]
Message-ID: <20170811003621-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20170810213511.GB10017@redhat.com>
On Thu, Aug 10, 2017 at 10:35:11PM +0100, Richard W.M. Jones wrote:
> On Fri, Aug 11, 2017 at 12:31:44AM +0300, Michael S. Tsirkin wrote:
> > Then we probably should fail probe if vq size is too small.
>
> What does this mean?
>
> Rich.
We must prevent driver from submitting s/g lists > vq size to device.
Either tell linux to avoid s/g lists that are too long, or
simply fail request if this happens, or refuse to attach driver to device.
Later option would look something like this within probe:
for (i = VIRTIO_SCSI_VQ_BASE; i < num_vqs; i++)
if (vqs[i]->num < MAX_SG_USED_BY_LINUX)
goto err;
I don't know what's MAX_SG_USED_BY_LINUX though.
> --
> Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
> Read my programming and virtualization blog: http://rwmj.wordpress.com
> virt-builder quickly builds VMs from scratch
> http://libguestfs.org/virt-builder.1.html
next prev parent reply other threads:[~2017-08-10 21:41 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-10 16:40 [PATCH 0/2] virtio_scsi: Set can_queue based on size of virtqueue Richard W.M. Jones
2017-08-10 16:40 ` [PATCH 1/2] virtio: Reduce BUG if total_sg > virtqueue size to WARN Richard W.M. Jones
2017-08-10 16:47 ` Paolo Bonzini
2017-08-10 21:21 ` Michael S. Tsirkin
2017-08-10 21:30 ` Richard W.M. Jones
2017-08-10 21:31 ` Michael S. Tsirkin
2017-08-10 21:35 ` Richard W.M. Jones
2017-08-10 21:41 ` Michael S. Tsirkin [this message]
2017-08-10 21:50 ` Richard W.M. Jones
2017-08-11 14:09 ` Paolo Bonzini
2017-08-11 17:23 ` Michael S. Tsirkin
2017-08-11 18:36 ` Paolo Bonzini
2017-08-10 16:40 ` [PATCH 2/2] virtio: virtio_scsi: Set can_queue to the length of the virtqueue Richard W.M. Jones
2017-08-10 16:46 ` Paolo Bonzini
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