Messages in this thread | | | Date | Wed, 17 Apr 2024 08:06:31 -0700 | Subject | Re: [PATCH v3 1/1] x86/fred: Fix INT80 emulation for FRED | From | Xin Li <> |
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On 4/17/2024 2:38 AM, Borislav Petkov wrote: > On Tue, Apr 16, 2024 at 11:30:01PM -0700, Xin Li (Intel) wrote: >> 3) The FRED kernel entry handler does *NOT* dispatch INT instructions, >> which is of event type EVENT_TYPE_SWINT, so compared with >> do_int80_emulation(), there is no need to do any user mode check. > > What does that mean? > > An event handler doesn't dispatch INT insns? > > /me is confused. >
Maybe better to say?
The FRED kernel entry handler fred_entry_from_kernel() calls fred_bad_type() if an event is of type EVENT_TYPE_SWINT because Kernel does not use INT insns! So if the kernel is handling an INT insn, it can only be from a user level application.
>> + * A dedicated FRED INT80 handler duplicates quite a bit of the code in >> + * do_int80_emulation(), but it avoids sprinkling more tests and seems >> + * more readable. Just remember that we can always unify common stuff >> + * later if it turns out that it won't diverge anymore, i.e., after the >> + * FRED code settles. >> + */ > > And this is talking about duplication above and that text is duplicated > from the commit message. :)
I wanted to keep it as a TODO. I can remove it in the next iteration.
> > I'll zap it when applying. > > Thx. >
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