Re: [PATCH v2 3/4] board: Add QEMU m68k virt board support

Kuan-Wei Chiu
2025-12-29T14:45:46Z

Hi Daniel,

On Mon, Dec 29, 2025 at 10:42:54AM +0900, Daniel Palmer wrote:
> Hi Kuan-Wei,
>
> On Mon, 29 Dec 2025 at 04:13, Kuan-Wei Chiu <visitorckw@gmail.com> wrote:
> > >
> > > One thing I found when I did the bootinfo parsing in my version is if
> > > I corrupted (during relocation etc) the bootinfo this type of loop
> > > would often get stuck forever.
> > > I'm not sure what the technical limit of the number of bootinfo
> > > entries is but bounding this to something reasonable feels like a good
> > > idea.
> >
> > In that scenario, I assume the correct error handling would be to add a
> > loop limit and trigger a panic() if exceeded?
>
> Yeah I think so, if you didn't find the last bootinfo entry within
> some reasonable bounds everything is probably broken and you shouldn't
> continue.
> I think for most real machines (Amiga etc) there aren't many entries
> but for the virt machine maybe there is an entry per virtio mmio
> device so there might actually be a lot of them there.

So the problem becomes determining a reasonable limit.

I think we can safely assume the bootinfo buffer won't exceed a 4KB
page size. Since the minimum record size is 4 bytes (tag + size),
setting the maximum records to 4096 / 4 =1024 should be a safe
assumption?

Regards,
Kuan-Wei