Re: [PATCH v2 00/13] objtool: Detect and warn about indirect calls in __nocfi functions

Peter Zijlstra
2025-05-02T08:41:47Z

On Thu, May 01, 2025 at 11:30:18AM -0700, Sean Christopherson wrote:

> Uh, aren't you making this way more complex than it needs to be?

Possibly :-)

> IIUC, KVM never
> uses the FRED hardware entry points, i.e. the FRED entry tables don't need to be
> in place because they'll never be used. The only bits of code KVM needs is the
> __fred_entry_from_kvm() glue.

But __fred_entry_from_kvm() calls into fred_extint(), which then
directly uses the fred sysvec_table[] for dispatch. How would we not
have to set up that table?

> Lightly tested, but this combo works for IRQs and NMIs on non-FRED hardware.

So the FRED NMI code is significantly different from the IDT NMI code
and I really didn't want to go mixing those.

If we get a nested NMI I don't think it'll behave well.