linux-kernel - Re: [PATCH v2 34/50] KVM: x86: Unify pr_fmt to use module name for all KVM modules

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Message-ID: <aa3be096-4f05-b653-b801-e102abe01903@xen.org>
Date:   Thu, 1 Dec 2022 10:43:18 +0000
From:   Paul Durrant <xadimgnik@...il.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Marc Zyngier <maz@...nel.org>,
        Huacai Chen <chenhuacai@...nel.org>,
        Aleksandar Markovic <aleksandar.qemu.devel@...il.com>,
        Anup Patel <anup@...infault.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Claudio Imbrenda <imbrenda@...ux.ibm.com>,
        Matthew Rosato <mjrosato@...ux.ibm.com>,
        Eric Farman <farman@...ux.ibm.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        David Woodhouse <dwmw2@...radead.org>
Cc:     James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Atish Patra <atishp@...shpatra.org>,
        David Hildenbrand <david@...hat.com>, kvm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
        kvmarm@...ts.cs.columbia.edu, linux-mips@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, kvm-riscv@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, Yuan Yao <yuan.yao@...el.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Isaku Yamahata <isaku.yamahata@...el.com>,
        Philippe Mathieu-Daudé <philmd@...aro.org>,
        Fabiano Rosas <farosas@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Kai Huang <kai.huang@...el.com>, Chao Gao <chao.gao@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v2 34/50] KVM: x86: Unify pr_fmt to use module name for
 all KVM modules

On 30/11/2022 23:09, Sean Christopherson wrote:
> Define pr_fmt using KBUILD_MODNAME for all KVM x86 code so that printks
> use consistent formatting across common x86, Intel, and AMD code.  In
> addition to providing consistent print formatting, using KBUILD_MODNAME,
> e.g. kvm_amd and kvm_intel, allows referencing SVM and VMX (and SEV and
> SGX and ...) as technologies without generating weird messages, and
> without causing naming conflicts with other kernel code, e.g. "SEV: ",
> "tdx: ", "sgx: " etc.. are all used by the kernel for non-KVM subsystems.
> 
> Opportunistically move away from printk() for prints that need to be
> modified anyways, e.g. to drop a manual "kvm: " prefix.
> 
> Opportunistically convert a few SGX WARNs that are similarly modified to
> WARN_ONCE; in the very unlikely event that the WARNs fire, odds are good
> that they would fire repeatedly and spam the kernel log without providing
> unique information in each print.
> 
> Note, defining pr_fmt yields undesirable results for code that uses KVM's
> printk wrappers, e.g. vcpu_unimpl().  But, that's a pre-existing problem
> as SVM/kvm_amd already defines a pr_fmt, and thankfully use of KVM's
> wrappers is relatively limited in KVM x86 code.
> 
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
[snip]
> diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
> index b246decb53a9..3bf7d69373cf 100644
> --- a/arch/x86/kvm/xen.c
> +++ b/arch/x86/kvm/xen.c
> @@ -5,6 +5,7 @@
>    *
>    * KVM Xen emulation
>    */
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>   
>   #include "x86.h"
>   #include "xen.h"

Reviewed-by: Paul Durrant <paul@....org>