Re: [PATCH] ix86: really make user_mode() work correctly for VM86 mode

From: Ingo Molnar
Date: Fri May 29 2015 - 03:49:29 EST



* Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:

> On May 28, 2015 1:16 AM, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
> >
> > While commit efa7045103 ("x86/asm/entry: Make user_mode() work
> > correctly if regs came from VM86 mode") claims that "user_mode() is now
> > identical to user_mode_vm()", this wasn't actually the case - no prior
> > commit made it so.
>
> That's embarrassing! I'm not sure how I screwed that up.

I should have noticed it too :-/

In fact I remember that I wanted to double check it all because the algorithmic
complexity of the new test looked suspiciously too simple on the 32-bit side (we
_did_ have a legitimate reason to keep the API split originally) - but forgot
about it.

> Acked-by: Andy Lutomirski <luto@xxxxxxxxxx>
>
> This is needed for x86/urgent.

Yeah, queued it up.

> [...] I'll see if I can write a simple test case, too. My old do_bounds test
> should be a good start.

That kind of test would be absolutely fantastic to have.

Thanks,

Ingo
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