From mboxrd@z Thu Jan  1 00:00:00 1970
From: Neo Jia <cjia@nvidia.com>
Subject: Re: [Qemu-devel] [PATCH v6 1/4] vfio: Mediated device Core driver
Date: Tue, 16 Aug 2016 13:30:06 -0700
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Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	"Song, Jike" <jike.song@intel.com>,
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To: Alex Williamson <alex.williamson@redhat.com>
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On Mon, Aug 15, 2016 at 04:47:41PM -0600, Alex Williamson wrote:
> On Mon, 15 Aug 2016 12:59:08 -0700
> Neo Jia <cjia@nvidia.com> wrote:
> 
> > > > >
> > > > > I'm not sure a comma separated list makes sense here, for both
> > > > > simplicity in the kernel and more fine grained error reporting, we
> > > > > probably want to start/stop them individually.  Actually, why is it
> > > > > that we can't use the mediated device being opened and released to
> > > > > automatically signal to the backend vendor driver to commit and release
> > > > > resources? I don't fully understand why userspace needs this interface.  
> > > 
> 
> That doesn't give an individual user the ability to stop and start
> their devices though, because in order for a user to have write
> permissions there, they get permission to DoS other users by pumping
> arbitrary UUIDs into those files.  By placing start/stop per mdev, we
> have mdev level granularity of granting start/stop privileges.  Really
> though, do we want QEMU fumbling around through sysfs or do we want an
> interface through the vfio API to perform start/stop?  Thanks,

Hi Alex,

I think those two suggests make sense, so we will move the "start/stop"
under mdev sysfs. 

This will be incorporated in our next v7 patch and by doing that, it will make
the locking scheme easier.

Thanks,
Neo

> 
> Alex