Re: [PATCH 0/2] hw/gpio/aspeed: Don't let guests modify input pins

[Peter Delevoryas]

On Thu, Jul 07, 2022 at 12:17:29AM -0700, Peter Delevoryas wrote:
> The fby35 OpenBMC sysvinit scripts check various GPIO pins at start and
> decide where to start IPMB daemons for each slot in the sled (4 slots max).
> It only starts an IPMB daemon if the slot GPIO pins indicate that it's
> present and powered on.
> 
> I've been simulating some input pins by setting their value in the machine
> reset function. I think a proper solution would be to add input pins to the
> Aspeed GPIO code and create devices that force the pins high or low
> appropriately, but for now setting the QOM property seemed fine.
> 
> But, I noticed that while the values were set initially, something in the
> boot process resets all the values I set to "low". I imagine something in
> userspace or the driver is blanket writing zero to the data registers. I
> think the Aspeed GPIO controller probably shouldn't be changing the value of
> input pins in this case.
> 
> To fix this, we could just make sure that aspeed_gpio_update() never sets
> the value of an input pin. However, that would also prevent my code in
> fby35_reset from initializing the input pins to some special value. So, to
> support the QOM property setup use-case, I added a "force" parameter. Kinda
> hacky, but it was the simplest thing I could think of.
> 
> Thanks,
> Peter

My gitconfig was messed up, I was using the maintainers.pl script in my
send-email.ccCmd, but that doesn't work for the cover letter.  So, it just sent
the cover letter to me. I didn't notice it in test emailing cause I usually just
test sending to myself. Sorry about this. Hopefully I should finally have
my email configuration fixed at this point...I hope.

Peter

> 
> Peter Delevoryas (2):
>   hw/gpio/aspeed: Don't let guests modify input pins
>   aspeed: Add fby35-bmc slot GPIO's
> 
>  hw/arm/aspeed.c       | 14 +++++++++++++-
>  hw/gpio/aspeed_gpio.c | 22 ++++++++++++----------
>  2 files changed, 25 insertions(+), 11 deletions(-)
> 
> -- 
> 2.36.1
>