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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 D9CADC3F2CD for ; Mon, 2 Mar 2020 16:32:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F8E5222C4 for ; Mon, 2 Mar 2020 16:32:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HLyVTYJw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727306AbgCBQcA (ORCPT ); Mon, 2 Mar 2020 11:32:00 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:45311 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727142AbgCBQcA (ORCPT ); Mon, 2 Mar 2020 11:32:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583166719; 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=SV2DzgE7/GVCHxe1MyF7cvm3oaLFW5XDl1ckEgBzooo=; b=HLyVTYJwLGLub/iQGFkQUC4vP3fp3+N+UVIuzfhLcE9+IjkKQ+c+Ii5d9flBxFnIK4xyOG AP93dm2So41DfcD1D2I8BR3Ij0tTFvgEIwycANHLpffbIaEDKmu6QAfEALk5aYKw9KQYAk bnoWUc8PzZxbbOoED1J30s/kKNI21to= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-105-T9T-YsjBNd2jfGFgxGkMaQ-1; Mon, 02 Mar 2020 11:31:58 -0500 X-MC-Unique: T9T-YsjBNd2jfGFgxGkMaQ-1 Received: by mail-wr1-f71.google.com with SMTP id d7so2074284wrr.0 for ; Mon, 02 Mar 2020 08:31:57 -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=SV2DzgE7/GVCHxe1MyF7cvm3oaLFW5XDl1ckEgBzooo=; b=INPyoA8ls947bMmeZpEwtcPxSG73/afV+42CCSGBjHc6xLPr96j0bC0igMbeOG9Iuz nU2/A9cuyMzhl3IPXVFUKZ8yLbpphd4UUf1uJDSBBztVeyjTwUd9BuV1zRx40+/+NpEO 8UPplr8wJT9wQnEIic2QDO0VxT/CZIZPpaDB6TgIjlSGIehtnhtFE5P2bWHRf8NFl3q/ c2aJiuWanc0GbuhC2qZZ2x2NkvxY1fBJFvyBJ8a0jHVh9pQaKM4Mq4Ee8ftpm1CHhrWP 6nnw1IK3qTbcI2zzlg/Dau+h+xT2PmEaaSRFim5d+MC6yQgN5dZ+xW609mEEV2xDo3JJ fDyA== X-Gm-Message-State: ANhLgQ1nzYFKdb2409glu8F5uSNGmfv9uAuHlmikxOVl0gQketsSaJhT +pvKyCuaLWolUIrAI5snkxsGd+4axOJorzOT0OvU685C3O6xBHDWAAutACQRtjcw4bwfxVRA23H +fjTNm4liYVpx X-Received: by 2002:a1c:ba87:: with SMTP id k129mr244108wmf.102.1583166716825; Mon, 02 Mar 2020 08:31:56 -0800 (PST) X-Google-Smtp-Source: ADFU+vuwUWhJ3l7EnEnCkmDlth1oK52o+owEznQwr9Yr2mH+gmpSnrmjs+4wXh/972NER3NftmL04w== X-Received: by 2002:a1c:ba87:: with SMTP id k129mr244074wmf.102.1583166716453; Mon, 02 Mar 2020 08:31:56 -0800 (PST) Received: from [192.168.178.40] ([151.30.85.6]) by smtp.gmail.com with ESMTPSA id i4sm16121618wmd.23.2020.03.02.08.31.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 02 Mar 2020 08:31:55 -0800 (PST) Subject: Re: [PATCH v2] KVM: X86: deprecate obsolete KVM_GET_CPUID2 ioctl To: linmiaohe , rkrcmar@redhat.com, sean.j.christopherson@intel.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 Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org References: <1582773688-4956-1-git-send-email-linmiaohe@huawei.com> From: Paolo Bonzini Message-ID: Date: Mon, 2 Mar 2020 17:31:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <1582773688-4956-1-git-send-email-linmiaohe@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 27/02/20 04:21, linmiaohe wrote: > From: Miaohe Lin > > When kvm_vcpu_ioctl_get_cpuid2() fails, we set cpuid->nent to the value of > vcpu->arch.cpuid_nent. But this is in vain as cpuid->nent is not copied to > userspace by copy_to_user() from call site. Also cpuid->nent is not updated > to indicate how many entries were retrieved on success case. So this ioctl > is straight up broken. And in fact, it's not used anywhere. So it should be > deprecated. > > Suggested-by: Paolo Bonzini > Signed-off-by: Miaohe Lin > --- > arch/x86/kvm/cpuid.c | 20 -------------------- > arch/x86/kvm/cpuid.h | 3 --- > arch/x86/kvm/x86.c | 16 ++-------------- > include/uapi/linux/kvm.h | 1 + > tools/include/uapi/linux/kvm.h | 1 + > 5 files changed, 4 insertions(+), 37 deletions(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index b1c469446b07..5e041a1282b8 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -261,26 +261,6 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, > return r; > } > > -int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, > - struct kvm_cpuid2 *cpuid, > - struct kvm_cpuid_entry2 __user *entries) > -{ > - int r; > - > - r = -E2BIG; > - if (cpuid->nent < vcpu->arch.cpuid_nent) > - goto out; > - r = -EFAULT; > - if (copy_to_user(entries, &vcpu->arch.cpuid_entries, > - vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2))) > - goto out; > - return 0; > - > -out: > - cpuid->nent = vcpu->arch.cpuid_nent; > - return r; > -} > - > static __always_inline void cpuid_mask(u32 *word, int wordnum) > { > reverse_cpuid_check(wordnum); > diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h > index 7366c618aa04..76555de38e1b 100644 > --- a/arch/x86/kvm/cpuid.h > +++ b/arch/x86/kvm/cpuid.h > @@ -19,9 +19,6 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu, > int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, > struct kvm_cpuid2 *cpuid, > struct kvm_cpuid_entry2 __user *entries); > -int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, > - struct kvm_cpuid2 *cpuid, > - struct kvm_cpuid_entry2 __user *entries); > bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, > u32 *ecx, u32 *edx, bool check_limit); > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index ddd1d296bd20..a6d99abedb2c 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -4295,21 +4295,9 @@ long kvm_arch_vcpu_ioctl(struct file *filp, > cpuid_arg->entries); > break; > } > + /* KVM_GET_CPUID2 is deprecated, should not be used. */ > case KVM_GET_CPUID2: { > - struct kvm_cpuid2 __user *cpuid_arg = argp; > - struct kvm_cpuid2 cpuid; > - > - r = -EFAULT; > - if (copy_from_user(&cpuid, cpuid_arg, sizeof(cpuid))) > - goto out; > - r = kvm_vcpu_ioctl_get_cpuid2(vcpu, &cpuid, > - cpuid_arg->entries); > - if (r) > - goto out; > - r = -EFAULT; > - if (copy_to_user(cpuid_arg, &cpuid, sizeof(cpuid))) > - goto out; > - r = 0; > + r = -EINVAL; > break; > } > case KVM_GET_MSRS: { > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 4b95f9a31a2f..61524780603d 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1380,6 +1380,7 @@ struct kvm_s390_ucas_mapping { > #define KVM_GET_LAPIC _IOR(KVMIO, 0x8e, struct kvm_lapic_state) > #define KVM_SET_LAPIC _IOW(KVMIO, 0x8f, struct kvm_lapic_state) > #define KVM_SET_CPUID2 _IOW(KVMIO, 0x90, struct kvm_cpuid2) > +/* KVM_GET_CPUID2 is deprecated, should not be used. */ > #define KVM_GET_CPUID2 _IOWR(KVMIO, 0x91, struct kvm_cpuid2) > /* Available with KVM_CAP_VAPIC */ > #define KVM_TPR_ACCESS_REPORTING _IOWR(KVMIO, 0x92, struct kvm_tpr_access_ctl) > diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h > index f0a16b4adbbd..2ef719af4c57 100644 > --- a/tools/include/uapi/linux/kvm.h > +++ b/tools/include/uapi/linux/kvm.h > @@ -1379,6 +1379,7 @@ struct kvm_s390_ucas_mapping { > #define KVM_GET_LAPIC _IOR(KVMIO, 0x8e, struct kvm_lapic_state) > #define KVM_SET_LAPIC _IOW(KVMIO, 0x8f, struct kvm_lapic_state) > #define KVM_SET_CPUID2 _IOW(KVMIO, 0x90, struct kvm_cpuid2) > +/* KVM_GET_CPUID2 is deprecated, should not be used. */ > #define KVM_GET_CPUID2 _IOWR(KVMIO, 0x91, struct kvm_cpuid2) > /* Available with KVM_CAP_VAPIC */ > #define KVM_TPR_ACCESS_REPORTING _IOWR(KVMIO, 0x92, struct kvm_tpr_access_ctl) > Queued, thanks. Paolo