Re: [PATCH 7/7] [v2] drivers/misc: introduce Freescale hypervisor management driver

For context, the most recent patch for the tile driver in question is here:

https://patchwork.kernel.org/patch/843892/

On 6/6/2011 5:23 PM, Konrad Rzeszutek Wilk wrote:

On Mon, Jun 06, 2011 at 05:01:36PM -0400, Chris Metcalf wrote:

quoted

On 6/6/2011 12:24 PM, Arnd Bergmann wrote:

quoted

On Monday 06 June 2011, Timur Tabi wrote:.

quoted

And what about my concern that my driver will be the only one in drivers/virt?

I have no doubt that more of these will come. Chris Metcalf is currently
looking for a home for his tilera hypervisor drivers, and we have the
microsoft hyperv drivers in drivers/staging, so they will hopefully
move to a proper place later. We also have similar drivers in other
places, e.g. drivers/ps3/ps3-sys-manager.c, drivers/s390/char/vmcp.c
or parts of drivers/xen.

It might help if someone (Arnd?) wanted to propose a statement of what
drivers/virt was really for.  If it's for any Linux driver that upcalls to

Was for? I am not seeing it in v3.0-rc2?

Sorry, maybe a questionable idiom, but please read past tense in the quoted
text as meaning present tense :-)

quoted

a hypervisor for any reason, then the Tilera paravirtualized drivers fit in
well.  If it's intended more for drivers that guests running under a
hypervisor can use to talk to the hypervisor itself (e.g. managing

I believe that the code that deals with specific subsystem (so block API
for example) would reside in subsystem directory (so drivers/block would have
your virtualization block driver). This allows the maintainer of block
to make sure your driver is OK.

Sure, makes sense.  The new push (as I understand it) is to group primarily
by function, not by bus or architecture.

quoted

notifications that a hypervisor delivers to a guest to cause it to shut
down or take other actions), then it doesn't seem like the Tilera

That looks to be arch/<x>/tilera/virt/ candidate?

Arnd, among others, has suggested that all drivers live in "drivers"
somewhere, so "arch/tile" may not be the best place.  (To be fair, I
originally had this driver in arch/tile/drivers/, so your idea is certainly
reasonable!)

quoted

paravirtualized device drivers belong there, since they're just using the
Tilera hypervisor synchronously to do I/O or get/set device and driver state.

Well, I/O sounds like block API or network API. But then you are also
doing management ioctl - which implies "drivers". "drivers/tilera" does not
work?

There is certainly precedent for drivers that don't fit cleanly into an
existing category to go in drivers/<arch>, e.g. drivers/s390,
drivers/parisc, etc.  There is also drivers/platform/x86, though that seems
to be for the bus "platform drivers" rather than just a random character
driver like the one in question.

I don't have a particular opinion here; I'm just hoping to develop enough
consensus that I can ask Linus to pull the driver without generating
controversy :-)

-- 
Chris Metcalf, Tilera Corp.
http://www.tilera.com