Re: stop breaking dosemu (Re: x86/kconfig/32: Rename CONFIG_VM86 and default it to 'n')

From: Stas Sergeev
Date: Fri Sep 04 2015 - 19:13:34 EST


05.09.2015 01:46, Raymond Jennings ÐÐÑÐÑ:
On 09/04/15 14:30, Stas Sergeev wrote:
05.09.2015 00:16, Stas Sergeev ÐÐÑÐÑ:
I agree. vm86() is a mess.
My point is that its risky parts and useless funtionality
is _already_ known (even I can point to the particular code
parts than can simply be removed). As such, it simply had
to be re-visited and cleaned up to match at least 1 and 3
(and then maybe 5). This wasn't done, and the knob was
introduced _instead_ of doing this.
Grr, I mean it was disabled by default instead of doing this,
and the knob was only proposed, not added.

You can't just pull vm86 out of the kernel anyway. dosemu is a userspace application that depends on it, so pulling this feature out would be a big fat regression, period.

I would personally rather not hear about how "it's a legacy program so its userbase is shrinking" used as any sort of excuse to ignore the fact that we shouldn't break userspace.

I can even say as a user that vm86 is important to me.

By all means, cleaning up vm86 is a good idea. But removing it or fencing it off with a strong deprecation doesn't sound like the right idea.
Yes, that's what I was saying lengthy.
Fencing it off may help those who does not use it,
and that's what most people here worry about.
BUT it will also do a big harm to those who uses it,
unless done properly like for modify_ldt(), or *sigh*
just with mmap_min_addr.
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