Re: [Qemu-devel] Testing sysbus devices

[Stephen Checkoway]

> On Feb 20, 2019, at 03:55, Laszlo Ersek <address@hidden> wrote:
> 
> I would strongly prefer if the guest-side view wouldn't change at all.

It sounds like sector protection isn't something you want and it's not 
something I currently need so unless that changes, I probably won't do anything 
with it.

My goal is merely to implement some missing flash functionality that I need to 
emulate some hardware that I have. My plan for doing this is to not change any 
defaults (except for a few bug fixes) while doing so. I'm happy for the qemu 
community to take as much or as little as it finds useful.

I'll send a patch series for review in the normal fashion, but if anyone wants 
to see my in-progress work, including tests, the diff is available here 
<https://github.com/qemu/qemu/compare/master...stevecheckoway:pflash02>.

For my own edification, I'm curious how you're currently dealing with some 
regions of flash that are protected. I believe Markus mentioned using multiple 
flash devices. Are you overlapping the address ranges?

The current pflash_cfi02.c code assumes, but doesn't check that both the total 
size of the chip as well as the size of each sector is a power of two. If you 
wanted say 7 MB of read/write flash and 1 MB of read-only flash, qemu might be 
willing to create a device with say 7 MB of storage, but it will definitely 
misbehave. (I added a check for that here 
<https://github.com/qemu/qemu/compare/master...stevecheckoway:pflash02#diff-d33881bd0ef099e2f46ebd4797c653bcR738>.)

Cheers,

Steve

-- 
Stephen Checkoway