From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: Having troubles binding an SR-IOV VF to
 uio_pci_generic on Amazon instance
Date: Thu, 1 Oct 2015 18:40:49 +0300
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On Thu, Oct 01, 2015 at 06:19:33PM +0300, Avi Kivity wrote:
> On 10/01/2015 06:11 PM, Michael S. Tsirkin wrote:
> >On Thu, Oct 01, 2015 at 02:32:19PM +0300, Avi Kivity wrote:
> >>>  We already agreed this kernel
> >>>is going to be tainted, and unsupportable.
> >>Yes.  So your only motivation in rejecting the patch is to get the author to
> >>write the ring translation patch and port it to all relevant drivers
> >>instead?
> >Not only that.
> >
> >To make sure users are aware they are doing insecure
> >things when using software poking at device BARs in sysfs.
> 
> I don't think you need to worry about that.  People who program DMA are
> aware of the damage is can cause.

People just install software and run it. They don't program DMA.

And I notice that no software (ab)using this seems to come with
documentation explaining the implications.

> If you want to be extra sure, have uio
> taint the kernel when bus mastering is enabled.

People don't notice kernel is tainted.  Denying module load will make
them notice.

-- 
MST