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From: Sean Christopherson <seanjc@google.com>
To: Will McVicker <willmcvicker@google.com>
Cc: Kees Cook <keescook@chromium.org>,
	kvm@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Sami Tolvanen <samitolvanen@google.com>,
	kvmarm <kvmarm@lists.cs.columbia.edu>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 09/17] perf/core: Use static_call to optimize perf_guest_info_callbacks
Date: Wed, 24 Aug 2022 16:45:03 +0000	[thread overview]
Message-ID: <YwZVj+8H4rGjEHyH@google.com> (raw)
In-Reply-To: <CABYd82ZmDbgmEGhdWOJ5Um8tiFd4TeQ-QZ2+xwxwqqQs6oi0xg@mail.gmail.com>

On Fri, Feb 18, 2022, Will McVicker wrote:
> On Sun, Feb 6, 2022 at 6:56 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > On Sun, Feb 06, 2022 at 09:28:52PM +0100, Peter Zijlstra wrote:
> > > On Sun, Feb 06, 2022 at 10:45:15AM -0800, Kees Cook wrote:
> > >
> > > > I'm digging through the macros to sort this out, but IIUC, an example of
> > > > the problem is:
> > > >
> > >
> > > > so the caller is expecting "unsigned int (*)(void)" but the prototype
> > > > of __static_call_return0 is "long (*)(void)":
> > > >
> > > > long __static_call_return0(void);
> > > >
> > > > Could we simply declare a type-matched ret0 trampoline too?
> > >
> > > That'll work for this case, but the next case the function will have
> > > arguments we'll need even more nonsense...
> >
> > Shouldn't the typeof() work there too, though? I.e. as long as the
> > return value can hold a "0", it'd work.
> >
> > > And as stated in that other email, there's tb_stub_func() having the
> > > exact same problem as well.
> >
> > Yeah, I'd need to go look at that again.
> >
> > > The x86_64 CFI patches had a work-around for this, that could trivially
> > > be lifted I suppose.
> >
> > Yeah, I think it'd be similar. I haven't had a chance to go look at that
> > again...

Peter and/or Kees, can you provide a pointer to the patches that could potentially
be used as a basis for fixing ARM CFI?  Or even better, send a patch to actually
fix this?  :-)
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  reply	other threads:[~2022-08-24 16:45 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-11  2:07 [PATCH v4 00/17] perf: KVM: Fix, optimize, and clean up callbacks Sean Christopherson
2021-11-11  2:07 ` Sean Christopherson
2021-11-11  2:07 ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 01/17] perf: Protect perf_guest_cbs with RCU Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  7:26   ` Paolo Bonzini
2021-11-11  7:26     ` Paolo Bonzini
2021-11-11  7:26     ` Paolo Bonzini
2021-11-11 10:47     ` Peter Zijlstra
2021-11-11 10:47       ` Peter Zijlstra
2021-11-11 10:47       ` Peter Zijlstra
2021-11-12  7:55       ` Paolo Bonzini
2021-11-12  7:55         ` Paolo Bonzini
2021-11-12  7:55         ` Paolo Bonzini
2021-11-11  2:07 ` [PATCH v4 02/17] KVM: x86: Register perf callbacks after calling vendor's hardware_setup() Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 03/17] KVM: x86: Register Processor Trace interrupt hook iff PT enabled in guest Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 04/17] perf: Stop pretending that perf can handle multiple guest callbacks Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 05/17] perf: Drop dead and useless guest "support" from arm, csky, nds32 and riscv Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 06/17] perf/core: Rework guest callbacks to prepare for static_call support Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 07/17] perf: Add wrappers for invoking guest callbacks Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 08/17] perf: Force architectures to opt-in to " Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 09/17] perf/core: Use static_call to optimize perf_guest_info_callbacks Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2022-02-02 18:43   ` Sean Christopherson
2022-02-04 17:35     ` Sami Tolvanen
2022-02-06 13:08       ` Peter Zijlstra
2022-02-06 18:45       ` Kees Cook
2022-02-06 20:28         ` Peter Zijlstra
2022-02-07  2:55           ` Kees Cook
2022-02-18 22:35             ` Will McVicker
2022-08-24 16:45               ` Sean Christopherson [this message]
2026-03-09 19:27             ` Carlos Llamas
2026-03-09 22:31               ` Sami Tolvanen
2026-03-10  3:26                 ` Carlos Llamas
2026-03-11 22:57                 ` [PATCH] static_call: use CFI-compliant return0 stubs Carlos Llamas
2026-03-11 23:14                   ` Peter Zijlstra
2026-03-12  0:16                     ` Carlos Llamas
2026-03-12  7:40                       ` Ard Biesheuvel
2026-03-12  8:07                         ` Peter Zijlstra
2026-03-12 17:18                           ` Carlos Llamas
2026-03-11 23:05                 ` [PATCH v4 09/17] perf/core: Use static_call to optimize perf_guest_info_callbacks Carlos Llamas
2021-11-11  2:07 ` [PATCH v4 10/17] KVM: x86: Drop current_vcpu for kvm_running_vcpu + kvm_arch_vcpu variable Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 11/17] KVM: x86: More precisely identify NMI from guest when handling PMI Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 12/17] KVM: Move x86's perf guest info callbacks to generic KVM Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 13/17] KVM: x86: Move Intel Processor Trace interrupt handler to vmx.c Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 14/17] KVM: arm64: Convert to the generic perf callbacks Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07 ` [PATCH v4 15/17] KVM: arm64: Hide kvm_arm_pmu_available behind CONFIG_HW_PERF_EVENTS=y Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11 21:49   ` Marc Zyngier
2021-11-11 21:49     ` Marc Zyngier
2021-11-11 21:49     ` Marc Zyngier
2021-11-11  2:07 ` [PATCH v4 16/17] KVM: arm64: Drop perf.c and fold its tiny bits of code into arm.c Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11 21:49   ` Marc Zyngier
2021-11-11 21:49     ` Marc Zyngier
2021-11-11 21:49     ` Marc Zyngier
2021-11-11  2:07 ` [PATCH v4 17/17] perf: Drop guest callback (un)register stubs Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11  2:07   ` Sean Christopherson
2021-11-11 11:19 ` [PATCH v4 00/17] perf: KVM: Fix, optimize, and clean up callbacks Peter Zijlstra
2021-11-11 11:19   ` Peter Zijlstra
2021-11-11 11:19   ` Peter Zijlstra

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