Re: [PATCH] ppc/pnv: Create BMC devices at machine init

[David Gibson]

On Thu, Nov 21, 2019 at 09:35:07AM -0600, Corey Minyard wrote:
> On Wed, Nov 20, 2019 at 09:05:07AM +1100, David Gibson wrote:
> > On Tue, Nov 19, 2019 at 07:49:33AM +0100, Cédric Le Goater wrote:
> > > On 19/11/2019 01:52, David Gibson wrote:
> > > > On Mon, Nov 18, 2019 at 10:22:22AM +0100, Cédric Le Goater wrote:
> > > >> The BMC of the OpenPOWER systems monitors the machine state using
> > > >> sensors, controls the power and controls the access to the PNOR flash
> > > >> device containing the firmware image required to boot the host.
> > > >>
> > > >> QEMU models the power cycle process, access to the sensors and access
> > > >> to the PNOR device. But, for these features to be available, the QEMU
> > > >> PowerNV machine needs two extras devices on the command line, an IPMI
> > > >> BT device for communication and a BMC backend device:
> > > >>
> > > >>   -device ipmi-bmc-sim,id=bmc0 -device isa-ipmi-bt,bmc=bmc0,irq=10
> > > >>
> > > >> The BMC properties are then defined accordingly in the device tree and
> > > >> OPAL self adapts. If a BMC device and an IPMI BT device are not
> > > >> available, OPAL does not try to communicate with the BMC in any
> > > >> manner. This is not how real systems behave.
> > > >>
> > > >> To be closer to the default behavior, create an IPMI BMC simulator
> > > >> device and an IPMI BT device at machine initialization time. We loose
> > > >> the ability to define an external BMC device but there are benefits:
> > > >>
> > > >>   - a better match with real systems,
> > > >>   - a better test coverage of the OPAL code,
> > > >>   - system powerdown and reset commands that work,
> > > >>   - a QEMU device tree compliant with the specifications (*).
> > > >>
> > > >> (*) Still needs a MBOX device.
> > > >>
> > > >> Signed-off-by: Cédric Le Goater <address@hidden>
> > > > 
> > > > This doesn't apply to ppc-for-5.0 for me.  I'm not sure which change
> > > > in there it's conflicting with, but there seems to be something.
> > > 
> > > Sorry I should have been more precise.
> > > 
> > > 
> > > This is because we need an IPMI patch to be merged first in 
> > > Corey's tree :
> > > 
> > >   ipmi: Add support to customize OEM functions
> > >   http://patchwork.ozlabs.org/patch/1185187/
> > > 
> > > and another one merged in the PPC tree: 
> > > 
> > >   ppc/pnv: Add HIOMAP commands
> > >   http://patchwork.ozlabs.org/patch/1185185/
> > > 
> > > 
> > > David, if Corey agrees, I think it would be simpler if you took 
> > > them all.
> > 
> > Ok.  Corey, could I get an Acked-by from you?
> 
> Sure
> 
> Acked-by: Corey Minyard <address@hidden>

Sorry, I wasn't clear.  It's the prerequisite "ipmi: Add support to
customize OEM functions" patch that I'm after an Acked-by for, rather
than thos one - I generally like to have that if I'm taking a patch
through my tree that isn't in the area I'm tagged as maintainer for.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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