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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 066B1C35646 for ; Fri, 21 Feb 2020 16:31:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB1EC20578 for ; Fri, 21 Feb 2020 16:31:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XGrGbbf7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727553AbgBUQbu (ORCPT ); Fri, 21 Feb 2020 11:31:50 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:23273 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726032AbgBUQbu (ORCPT ); Fri, 21 Feb 2020 11:31:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582302708; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=x+/PwYVfKF+sGaYhdBB/ka7rcNSOJveuT3O5v5Xs6QM=; b=XGrGbbf7Z4mAPjbwexqJ7IsLnJ5yHXohgwfNxReFPISrRudkd7aLJt8yY5ImgqBQzHqQUY vnIyoWFr1zkYlaoJGlHJTL5DTH/OcCLUCoHQrsZsnMX4gcbTVFqVwrZarB8XUt4fjY65gS nPh39pTOAKiAHwSwrhLivBRM5r5M5bw= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-61--R_eFUj0NvKTyAVnVWCB1g-1; Fri, 21 Feb 2020 11:31:47 -0500 X-MC-Unique: -R_eFUj0NvKTyAVnVWCB1g-1 Received: by mail-wm1-f69.google.com with SMTP id p26so834033wmg.5 for ; Fri, 21 Feb 2020 08:31:47 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=x+/PwYVfKF+sGaYhdBB/ka7rcNSOJveuT3O5v5Xs6QM=; b=YgVLOSdY9OhKaVoH0nvpHaUIFyUDmIOJx0KMVLBF2YzJ5oSJwYoqPnsDwpcx8Sq/Kl /FN5YP019t8XwHnzQU7e6S2IUxHzryG/5qSSCDUrlXUavEXSRC9KzunxxTGkgdCD5+Iy UuuDi7B/O4xvvEF5grXvf/R02GISAw1gYlf3Zkg+bSVBT378O1jSIBViJ59/VLzmyqDn +VfRfCyGZ25vkIZdsEy4UX+9pxnALYUen3WsnfI4Lw/tNhJgzl9u/pruqQ0mt61QnWRP a/vOgDDs+5dxZvCpkO9YCiWbUuNDzbOU2pavFOgVh4vBSpbE9HPyce6p/aI1Tm66oo3D vD8w== X-Gm-Message-State: APjAAAXhrxNZ33bsTmTxUC47ga5brZeVUKG9bk57T1NEDfOEAHL1C2wY 5ia9Y3+OCcieCUWFKvaC7p7G3+TPR30KpdMrzW6HZXnYgHZjL1RuoZHttP6pt7L9ov/mdjW9Ync T8QK4Ri8/XiV/iQMjOtID3xir X-Received: by 2002:a1c:f606:: with SMTP id w6mr4632378wmc.109.1582302706099; Fri, 21 Feb 2020 08:31:46 -0800 (PST) X-Google-Smtp-Source: APXvYqzHPzw+vtsYsE0OyDcSB1eD9HXtMyBCN3d5TeUuNu7HSh1hgyKVqB1VcO5l07mSlsTnqf40YA== X-Received: by 2002:a1c:f606:: with SMTP id w6mr4632358wmc.109.1582302705882; Fri, 21 Feb 2020 08:31:45 -0800 (PST) Received: from [192.168.178.40] ([151.20.135.128]) by smtp.gmail.com with ESMTPSA id w1sm4297148wmc.11.2020.02.21.08.31.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 21 Feb 2020 08:31:44 -0800 (PST) Subject: Re: [PATCH] KVM: X86: eliminate some meaningless code To: Sean Christopherson , linmiaohe Cc: rkrcmar@redhat.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org References: <1582293926-23388-1-git-send-email-linmiaohe@huawei.com> <20200221152358.GC12665@linux.intel.com> From: Paolo Bonzini Message-ID: Date: Fri, 21 Feb 2020 17:31:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20200221152358.GC12665@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/02/20 16:23, Sean Christopherson wrote: > > I'm guessing no VMM actually uses this ioctl(), e.g. neither Qemu or CrosVM > use it, which is why the broken behavior has gone unnoticed. Don't suppose > you'd want to write a selftest to hammer KVM_{SET,GET}_CPUID2? > > int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, > struct kvm_cpuid2 *cpuid, > struct kvm_cpuid_entry2 __user *entries) > { > if (cpuid->nent < vcpu->arch.cpuid_nent) > return -E2BIG; > > if (copy_to_user(entries, &vcpu->arch.cpuid_entries, > vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2))) > return -EFAULT; > > cpuid->nent = vcpu->arch.cpuid_nent; > > return 0; > } I would just drop KVM_GET_CPUID2 altogether and see if someone complains. Paolo