From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 508CDBA3F; Fri, 2 May 2025 05:49:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746164959; cv=none; b=sNh7tRf05/t0YssUX2d1zNp7dL7u6mlT2O0Kt58GyzZtBu7Py70Jyz9/AXtuBnlvUorvxnyxSomnTPAXOxM/k7F4nwrvTg7cFb/Nma46vHg7I/BHYXBMaXHQ6/rmdl7s+zGe4fu846UBXCGC88eYT0pGBB1dVgYs7CdpaSO1yAU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746164959; c=relaxed/simple; bh=xHuDiwaHi25BWrOdJavtW7Xs+O7UjhjxqydntQpALqY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=aPcf9CVhF9UmDFI0mp4MZYQ0Dso0CDGKm2NQ4y+QcwYBX6AaiJL0MZrCaAc6kEHonB1oOwaz3M90ju1qoPwmNQ+//unNkvAwZ/nU/1noSz6SAHiHhLoKksOcPj5Ai4/jjOD4Mi9+VHdEcMCcx/oLAvWQ2NDcUbUE8eaOu7JT0qw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=QNHgla/6; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="QNHgla/6" Received: from [192.168.7.202] ([71.202.166.45]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 5425mgEN1781141 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Thu, 1 May 2025 22:48:43 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 5425mgEN1781141 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025042001; t=1746164924; bh=UPrgXeeHDSbppfXKlFI7+ZZbVFJc1sBHvqfJ3YIqx60=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=QNHgla/6mBMJgp4DmEzvjI9pcvfVN1AMs4cpGZJq2JBUfGbHcB9acot2g/bgQGktc 18qpb94Jy2r+RT5E9zUkpFLLsrV3Z3/i70nJ+Dh+WTpdCsZ+bEy40c+lxFidRpCSKD RcNA8Yg9dvgJ978NzgkgtdYqjKvXlHNKEHrVnYOa67p79PEEX6vGALYMxlIAEfKghW DM/OlDNVra5aggOOi76AhTcuZIvUMePIFwDClF/1v0o7EYk0G9wmAHQxo6AnUG/EYb N2BN2I0wrrK0Y3lw9W0AkaAWkLlIQJsN4PZ7YC6a5LaCim78ZaBem0nJZCSNIaQFsC CJOJPI+IHLuOQ== Message-ID: <9b112e40-d281-422c-b862-3c073b3c7239@zytor.com> Date: Thu, 1 May 2025 22:48:42 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 00/13] objtool: Detect and warn about indirect calls in __nocfi functions To: Sean Christopherson , Peter Zijlstra Cc: "H. Peter Anvin" , x86@kernel.org, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, pbonzini@redhat.com, ardb@kernel.org, kees@kernel.org, Arnd Bergmann , gregkh@linuxfoundation.org, jpoimboe@kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-efi@vger.kernel.org, samitolvanen@google.com, ojeda@kernel.org References: <20250430110734.392235199@infradead.org> <8B86A3AE-A296-438C-A7A7-F844C66D0198@zytor.com> <20250430190600.GQ4439@noisy.programming.kicks-ass.net> <20250501103038.GB4356@noisy.programming.kicks-ass.net> <20250501153844.GD4356@noisy.programming.kicks-ass.net> Content-Language: en-US From: Xin Li Autocrypt: addr=xin@zytor.com; keydata= xsDNBGUPz1cBDACS/9yOJGojBFPxFt0OfTWuMl0uSgpwk37uRrFPTTLw4BaxhlFL0bjs6q+0 2OfG34R+a0ZCuj5c9vggUMoOLdDyA7yPVAJU0OX6lqpg6z/kyQg3t4jvajG6aCgwSDx5Kzg5 Rj3AXl8k2wb0jdqRB4RvaOPFiHNGgXCs5Pkux/qr0laeFIpzMKMootGa4kfURgPhRzUaM1vy bsMsL8vpJtGUmitrSqe5dVNBH00whLtPFM7IbzKURPUOkRRiusFAsw0a1ztCgoFczq6VfAVu raTye0L/VXwZd+aGi401V2tLsAHxxckRi9p3mc0jExPc60joK+aZPy6amwSCy5kAJ/AboYtY VmKIGKx1yx8POy6m+1lZ8C0q9b8eJ8kWPAR78PgT37FQWKYS1uAroG2wLdK7FiIEpPhCD+zH wlslo2ETbdKjrLIPNehQCOWrT32k8vFNEMLP5G/mmjfNj5sEf3IOKgMTMVl9AFjsINLHcxEQ 6T8nGbX/n3msP6A36FDfdSEAEQEAAc0WWGluIExpIDx4aW5Aenl0b3IuY29tPsLBDQQTAQgA NxYhBIUq/WFSDTiOvUIqv2u9DlcdrjdRBQJlD89XBQkFo5qAAhsDBAsJCAcFFQgJCgsFFgID AQAACgkQa70OVx2uN1HUpgv/cM2fsFCQodLArMTX5nt9yqAWgA5t1srri6EgS8W3F+3Kitge tYTBKu6j5BXuXaX3vyfCm+zajDJN77JHuYnpcKKr13VcZi1Swv6Jx1u0II8DOmoDYLb1Q2ZW v83W55fOWJ2g72x/UjVJBQ0sVjAngazU3ckc0TeNQlkcpSVGa/qBIHLfZraWtdrNAQT4A1fa sWGuJrChBFhtKbYXbUCu9AoYmmbQnsx2EWoJy3h7OjtfFapJbPZql+no5AJ3Mk9eE5oWyLH+ QWqtOeJM7kKvn/dBudokFSNhDUw06e7EoVPSJyUIMbYtUO7g2+Atu44G/EPP0yV0J4lRO6EA wYRXff7+I1jIWEHpj5EFVYO6SmBg7zF2illHEW31JAPtdDLDHYcZDfS41caEKOQIPsdzQkaQ oW2hchcjcMPAfyhhRzUpVHLPxLCetP8vrVhTvnaZUo0xaVYb3+wjP+D5j/3+hwblu2agPsaE vgVbZ8Fx3TUxUPCAdr/p73DGg57oHjgezsDNBGUPz1gBDAD4Mg7hMFRQqlzotcNSxatlAQNL MadLfUTFz8wUUa21LPLrHBkUwm8RujehJrzcVbPYwPXIO0uyL/F///CogMNx7Iwo6by43KOy g89wVFhyy237EY76j1lVfLzcMYmjBoTH95fJC/lVb5Whxil6KjSN/R/y3jfG1dPXfwAuZ/4N cMoOslWkfZKJeEut5aZTRepKKF54T5r49H9F7OFLyxrC/uI9UDttWqMxcWyCkHh0v1Di8176 jjYRNTrGEfYfGxSp+3jYL3PoNceIMkqM9haXjjGl0W1B4BidK1LVYBNov0rTEzyr0a1riUrp Qk+6z/LHxCM9lFFXnqH7KWeToTOPQebD2B/Ah5CZlft41i8L6LOF/LCuDBuYlu/fI2nuCc8d m4wwtkou1Y/kIwbEsE/6RQwRXUZhzO6llfoN96Fczr/RwvPIK5SVMixqWq4QGFAyK0m/1ap4 bhIRrdCLVQcgU4glo17vqfEaRcTW5SgX+pGs4KIPPBE5J/ABD6pBnUUAEQEAAcLA/AQYAQgA JhYhBIUq/WFSDTiOvUIqv2u9DlcdrjdRBQJlD89ZBQkFo5qAAhsMAAoJEGu9DlcdrjdR4C0L /RcjolEjoZW8VsyxWtXazQPnaRvzZ4vhmGOsCPr2BPtMlSwDzTlri8BBG1/3t/DNK4JLuwEj OAIE3fkkm+UG4Kjud6aNeraDI52DRVCSx6xff3bjmJsJJMb12mWglN6LjdF6K+PE+OTJUh2F dOhslN5C2kgl0dvUuevwMgQF3IljLmi/6APKYJHjkJpu1E6luZec/lRbetHuNFtbh3xgFIJx 2RpgVDP4xB3f8r0I+y6ua+p7fgOjDLyoFjubRGed0Be45JJQEn7A3CSb6Xu7NYobnxfkwAGZ Q81a2XtvNS7Aj6NWVoOQB5KbM4yosO5+Me1V1SkX2jlnn26JPEvbV3KRFcwV5RnDxm4OQTSk PYbAkjBbm+tuJ/Sm+5Yp5T/BnKz21FoCS8uvTiziHj2H7Cuekn6F8EYhegONm+RVg3vikOpn gao85i4HwQTK9/D1wgJIQkdwWXVMZ6q/OALaBp82vQ2U9sjTyFXgDjglgh00VRAHP7u1Rcu4 l75w1xInsg== In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/1/2025 11:30 AM, Sean Christopherson wrote: > From c50fb5a8a46058bbcfdcac0a100c2aa0f7f68f1c Mon Sep 17 00:00:00 2001 > From: Sean Christopherson > Date: Thu, 1 May 2025 11:10:39 -0700 > Subject: [PATCH 2/2] x86/fred: KVM: VMX: Always use FRED for IRQ+NMI when > CONFIG_X86_FRED=y > > Now that FRED provides C-code entry points for handling IRQ and NMI exits, > use the FRED infrastructure for forwarding all such events even if FRED > isn't supported in hardware. Avoiding the non-FRED assembly trampolines > into the IDT handlers for IRQs eliminates the associated non-CFI indirect > call (KVM performs a CALL by doing a lookup on the IDT using the IRQ > vector). > > Force FRED for 64-bit kernels if KVM_INTEL is enabled, as the benefits of > eliminating the IRQ trampoline usage far outwieghts the code overhead for > FRED. > > Suggested-by: Peter Zijlstra > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/Kconfig | 1 + > arch/x86/kvm/vmx/vmx.c | 4 ++-- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index 2eeffcec5382..712a2ff28ce4 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -95,6 +95,7 @@ config KVM_SW_PROTECTED_VM > config KVM_INTEL > tristate "KVM for Intel (and compatible) processors support" > depends on KVM && IA32_FEAT_CTL > + select X86_FRED if X86_64 I LOVE this change, but not sure if everyone is happy with it. > select KVM_GENERIC_PRIVATE_MEM if INTEL_TDX_HOST > select KVM_GENERIC_MEMORY_ATTRIBUTES if INTEL_TDX_HOST > help > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index ef2d7208dd20..2ea89985107d 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -6995,7 +6995,7 @@ static void handle_external_interrupt_irqoff(struct kvm_vcpu *vcpu, > return; > > kvm_before_interrupt(vcpu, KVM_HANDLING_IRQ); > - if (cpu_feature_enabled(X86_FEATURE_FRED)) > + if (IS_ENABLED(CONFIG_X86_FRED)) "if (IS_ENABLED(CONFIG_X86_64))"? > fred_entry_from_kvm(EVENT_TYPE_EXTINT, vector); > else > vmx_do_interrupt_irqoff(gate_offset((gate_desc *)host_idt_base + vector)); > @@ -7268,7 +7268,7 @@ noinstr void vmx_handle_nmi(struct kvm_vcpu *vcpu) > return; > > kvm_before_interrupt(vcpu, KVM_HANDLING_NMI); > - if (cpu_feature_enabled(X86_FEATURE_FRED)) > + if (IS_ENABLED(CONFIG_X86_FRED)) Ditto.