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Date:   Fri, 11 Nov 2022 09:58:20 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Li, Xin3" <xin3.li@intel.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "x86@kernel.org" <x86@kernel.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
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        "mingo@redhat.com" <mingo@redhat.com>,
        "bp@alien8.de" <bp@alien8.de>,
        "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
        "hpa@zytor.com" <hpa@zytor.com>,
        "Christopherson,, Sean" <seanjc@google.com>,
        "pbonzini@redhat.com" <pbonzini@redhat.com>,
        "Tian, Kevin" <kevin.tian@intel.com>
Subject: Re: [RESEND PATCH 2/6] x86/traps: add a system interrupt table for
 system interrupt dispatch
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On Thu, Nov 10, 2022 at 08:36:30PM +0000, Li, Xin3 wrote:
> > > > +#pragma GCC diagnostic push
> > > > +#pragma GCC diagnostic ignored "-Wcast-function-type"
> > >
> > > How does this not break CFI ?
> > 
> > I wasn't aware of it, will check.
> 
> CFI needs $(cc-option,-fsanitize=kcfi), which, reported on LWN on Jun, 2002,
> had not yet landed in the LLVM mainline (I'm using GCC).  So looks we are
> replying on people keeping an eye on it to make sure it's not broken?

We're relying on that warning you disabled.

> Even we are unable to test it now, we should find a solution.

You can test this just fine. Build llvm.git and compile a kernel with
CFI_CLANG=y. This is not hard, my ADL runs such a kernel as we speak.