Aims for BMC emulation in qemu

[Cédric Le Goater]

Hello,

On 05/23/2016 07:26 AM, Andrew Jeffery wrote:
> Hi Chris,
> 
> On Sat, 2016-05-21 at 22:32 +0000, Chris Austen wrote:
>> So in short I think we want to create a build environment that allows
>> for inaccurate systems.  Over time that environment should grow from
>> palmettoish to wedgeish, Zaius and witherspoonish
> 
> I tend to agree. 
> 
> My thoughts are that in general we should try to work upstream first,
> and to only send upstream something that's an accurate reflection of
> the hardware. However, sometimes there are work-arounds with desirable
> short-term benefits, and we should be able to accommodate these too.

yes. mainline qemu can also live with a slightly inaccurate model which 
we can patch later.

> As an alternative to a number of machines with different levels of
> accuracy, we can give the qemu fork on github a defined role: To host
> our integrated short-term work-arounds as we develop the right models
> to send upstream. As a concrete example, whilst the ftgmac100 model
> isn't functional, have the fork provide the Cadence GEM as a NIC. Once
> the ftgmac100 model is functional, send it upstream and replace the
> GEM.
>
> Any work-arounds included in the fork should have an obvious immediate
> benefit and a plan to phase them out, and if that's not the case then
> they should be rejected. If it's more work to maintain the hack than to
> implement an accurate model, then we should do the latter.

Are we planning to use travis to boot the generated flash image with qemu ?
and eventually run some tests in the guest ? 

> Is there any opposition to this approach?

Looks good to me. 


Here are some thoughts on devices we could work on to complete the model :

- uarts : quick one to get rid of the "serial8250: too much work for irq23"

- occ sensor model : to stress the kernel and user space.

- ftgmac100 : to be done.    

- bt : it would be interesting to establish a link with a powernv guest 
  or an ipmi host simulator. there is already a ipmi bmc similator.  

- smc : rfc available in my github. boots uboot. Mostly accurate I would
  say but a little ugly in some parts.  

- ...

Cheers,

C.