From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1AB1EC433ED for ; Wed, 21 Apr 2021 17:10:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2CF361454 for ; Wed, 21 Apr 2021 17:10:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242574AbhDURLL (ORCPT ); Wed, 21 Apr 2021 13:11:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:40420 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238034AbhDURKx (ORCPT ); Wed, 21 Apr 2021 13:10:53 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5606A61360; Wed, 21 Apr 2021 17:10:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1619025020; bh=vQW/O+ZRlOWfybjW1VBTul75liFN4bSm4NGQMUpQUt0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bLe+rypc/AwdIGixQpLnD3YnfRANOWDeSjFkhTfu2bu9XAezbNXlXjq8ttbMvesTs dS7Fs2XcrFBDivtz+XddlwOTQeb7OOnU583/I6hT2E6JMgShitGXLx+uy6QrsddQYz RoUmSUUwG8o+h82IA4MkGK7dAuU09qPIVzbE/u1dIbSMFnuw7TZAnIWHhpRX9sCVkc IYzaSDVRZyRFJ0FtRkmoZ5/AbJL3Ox4K7vDts12Fv80qKOPCBInSLxqFlvGJcrY9W4 +mNbg+JCcUIcz6vF3bM3iC51b4FbhFE94l01WZBgVQxDnCS0QqRvKWz4jk7HOpfYUk II82pwHBSlvyQ== Date: Wed, 21 Apr 2021 10:10:15 -0700 From: Nathan Chancellor To: Sean Christopherson Cc: Paolo Bonzini , Nick Desaulniers , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org, Kai Huang Subject: Re: [PATCH] KVM: x86: Fix implicit enum conversion goof in scattered reverse CPUID code Message-ID: References: <20210421010850.3009718-1-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210421010850.3009718-1-seanjc@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 20, 2021 at 06:08:50PM -0700, Sean Christopherson wrote: > Take "enum kvm_only_cpuid_leafs" in scattered specific CPUID helpers > (which is obvious in hindsight), and use "unsigned int" for leafs that > can be the kernel's standard "enum cpuid_leaf" or the aforementioned > KVM-only variant. Loss of the enum params is a bit disapponting, but > gcc obviously isn't providing any extra sanity checks, and the various Unfortunately, gcc's -Wenum-conversion is behind -Wextra rather than -Wall like clang. If you explicitly enable it with KCFLAGS=-Wenum-conversion to your make invocation, it will warn in the exact same way as clang: arch/x86/kvm/cpuid.c: In function 'kvm_set_cpu_caps': arch/x86/kvm/cpuid.c:499:29: warning: implicit conversion from 'enum kvm_only_cpuid_leafs' to 'enum cpuid_leafs' [-Wenum-conversion] 499 | kvm_cpu_cap_init_scattered(CPUID_12_EAX, | ^~~~~~~~~~~~ arch/x86/kvm/cpuid.c: In function '__do_cpuid_func': arch/x86/kvm/cpuid.c:837:31: warning: implicit conversion from 'enum kvm_only_cpuid_leafs' to 'enum cpuid_leafs' [-Wenum-conversion] 837 | cpuid_entry_override(entry, CPUID_12_EAX); | ^~~~~~~~~~~~ clang's warning for comparison/posterity: arch/x86/kvm/cpuid.c:499:29: warning: implicit conversion from enumeration type 'enum kvm_only_cpuid_leafs' to different enumeration type 'enum cpuid_leafs' [-Wenum-conversion] kvm_cpu_cap_init_scattered(CPUID_12_EAX, ~~~~~~~~~~~~~~~~~~~~~~~~~~ ^~~~~~~~~~~~ arch/x86/kvm/cpuid.c:837:31: warning: implicit conversion from enumeration type 'enum kvm_only_cpuid_leafs' to different enumeration type 'enum cpuid_leafs' [-Wenum-conversion] cpuid_entry_override(entry, CPUID_12_EAX); ~~~~~~~~~~~~~~~~~~~~ ^~~~~~~~~~~~ 2 warnings generated. > BUILD_BUG_ON() assertions ensure the input is in range. > > This fixes implicit enum conversions that are detected by clang-11. > > Fixes: 4e66c0cb79b7 ("KVM: x86: Add support for reverse CPUID lookup of scattered features") > Cc: Kai Huang > Signed-off-by: Sean Christopherson This makes GCC and clang happy in my brief testing. I assume this will get squashed but in case not, here are some tags: Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor > --- > > Hopefully it's not too late to squash this... > > arch/x86/kvm/cpuid.c | 5 +++-- > arch/x86/kvm/cpuid.h | 2 +- > 2 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 96e41e1a1bde..e9d644147bf5 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -365,7 +365,7 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, > } > > /* Mask kvm_cpu_caps for @leaf with the raw CPUID capabilities of this CPU. */ > -static __always_inline void __kvm_cpu_cap_mask(enum cpuid_leafs leaf) > +static __always_inline void __kvm_cpu_cap_mask(unsigned int leaf) > { > const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32); > struct kvm_cpuid_entry2 entry; > @@ -378,7 +378,8 @@ static __always_inline void __kvm_cpu_cap_mask(enum cpuid_leafs leaf) > kvm_cpu_caps[leaf] &= *__cpuid_entry_get_reg(&entry, cpuid.reg); > } > > -static __always_inline void kvm_cpu_cap_init_scattered(enum cpuid_leafs leaf, u32 mask) > +static __always_inline > +void kvm_cpu_cap_init_scattered(enum kvm_only_cpuid_leafs leaf, u32 mask) > { > /* Use kvm_cpu_cap_mask for non-scattered leafs. */ > BUILD_BUG_ON(leaf < NCAPINTS); > diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h > index eeb4a3020e1b..7bb4504a2944 100644 > --- a/arch/x86/kvm/cpuid.h > +++ b/arch/x86/kvm/cpuid.h > @@ -236,7 +236,7 @@ static __always_inline void cpuid_entry_change(struct kvm_cpuid_entry2 *entry, > } > > static __always_inline void cpuid_entry_override(struct kvm_cpuid_entry2 *entry, > - enum cpuid_leafs leaf) > + unsigned int leaf) > { > u32 *reg = cpuid_entry_get_reg(entry, leaf * 32); > > -- > 2.31.1.368.gbe11c130af-goog >