On Fri, Aug 11, 2017 at 12:41:47AM +0300, Michael S. Tsirkin wrote:
> 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.
Fair point. I would have thought (not knowing anything about how this
works in the kernel) that the driver should be able to split up
scatter-gather lists if they are larger than what the driver supports?
Anyway the commit message is derived from what Paolo told me on IRC,
so let's see what he says.
> 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
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