lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20131002015355.GD63102@lvm>
Date:	Wed, 2 Oct 2013 02:53:55 +0100
From:	Christoffer Dall <christoffer.dall@...aro.org>
To:	Kim Phillips <kim.phillips@...aro.org>
Cc:	gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	a.motakis@...tualopensystems.com, agraf@...e.de,
	alex.williamson@...hat.com, stuart.yoder@...escale.com,
	B07421@...escale.com, B16395@...escale.com, R65777@...escale.com,
	peter.maydell@...aro.org, santosh.shukla@...aro.org,
	kvm@...r.kernel.org
Subject: Re: RFC: (re-)binding the VFIO platform driver to a platform device

On Tue, Oct 01, 2013 at 05:02:44PM -0500, Kim Phillips wrote:
> On Tue, 1 Oct 2013 13:00:54 -0700
> Greg Kroah-Hartman <gregkh@...uxfoundation.org> wrote:
> 
> > On Tue, Oct 01, 2013 at 01:38:31PM -0500, Kim Phillips wrote:
> > > Hi,
> > > 
> > > Santosh and I are having a problem figuring out how to enable binding
> > > (and re-binding) platform devices to a platform VFIO driver (see
> > > Antonis' WIP: [1]) in an upstream-acceptable manner.
> > > 
> > > Binding platform drivers currently depends on a string match in the
> > > device node's compatible entry.  On an arndale, one can currently
> > > rebind the same device to the same driver like so:
> > > 
> > > echo 12ce0000.i2c > /sys/bus/platform/drivers/s3c-i2c/12ce0000.i2c/driver/unbind
> > > echo 12ce0000.i2c > /sys/bus/platform/drivers/s3c-i2c/bind
> > > 
> > > And one can bind it to the vfio-dt driver, as Antonis instructs, by
> > > appending a 'vfio-dt' string to the device tree compatible entry for
> > > the device.  Then this would work:
> > > 
> > > echo 12ce0000.i2c > /sys/bus/platform/drivers/s3c-i2c/12ce0000.i2c/driver/unbind
> > > echo 12ce0000.i2c > /sys/bus/platform/drivers/vfio-dt/bind
> > > 
> > > Consequently, the hack patch below [2] allows any platform device to be
> > > bound to the vfio-dt driver, without making changes to the device
> > > tree.  It's a hack because I don't see having any driver name specific
> > > code in drivers/base/bus.c being upstream acceptable.
> > 
> > You are correct.
> > 
> > What is wrong with just doing the above unbind/bind things through
> > sysfs, that is what it is there for, right?
> 
> The bind fails because the compatible string in the device tree doesn't
> match that of the VFIO platform driver, so driver_match_device always
> returns false.
> 
It sounds like this is not going to be pretty almost no matter what
we'll end up doing: Inherently VFIO is going to bind to a device without
the device tree entry for that device ever saying anything about VFIO.

How is this solved for PCI?  Can we use some analogy from that work to
construct the missing piece?

-Christoffer
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ