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,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 8740AC433DB for ; Thu, 28 Jan 2021 08:37:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D7F860235 for ; Thu, 28 Jan 2021 08:37:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231915AbhA1Ihm (ORCPT ); Thu, 28 Jan 2021 03:37:42 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:49871 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231509AbhA1Ihk (ORCPT ); Thu, 28 Jan 2021 03:37:40 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611822974; 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: in-reply-to:in-reply-to:references:references; bh=Nf0jnBmR9S7kgQakgFuMWWnzgzSE4QHvRdW36PL6dL8=; b=A2RrV93+HpUtkrWHL/7JqR1MXmF7QS01lfgek5Dcy7SAPJfLxXE7zD5fog83HqwVN9PVlm oCNC9Qpj2WT6YIgXSBctW1tdrhtHEfUuU7e//CvI8uHf1GKkotEcpZrNU3ONJSFapCAye8 Ni2fu4jV9gZbNSLL8+gXiooJth09UJ4= Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-313-daZz-jgeNqyjabXb2w9XLA-1; Thu, 28 Jan 2021 03:36:12 -0500 X-MC-Unique: daZz-jgeNqyjabXb2w9XLA-1 Received: by mail-ed1-f72.google.com with SMTP id n8so2832527edo.19 for ; Thu, 28 Jan 2021 00:36:11 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=Nf0jnBmR9S7kgQakgFuMWWnzgzSE4QHvRdW36PL6dL8=; b=P893Hhd1m8DvxgYuYf09hLSIkssBBBvvdnv3Nmvm9v2OT4tP7/zGDzBbHTUR61iBod oufCMsGWCUPkVMo44eVf8A7w/UI0JwTToELsT1Km7s/9cSXGDAdVgjI19ELq21hvz3TZ TIBd5LJppCy6O7uz6S5yJPZk6HO+QfwgCq2B0QTv0MhDxV+s7WPsnnZHWCnA13j6WQGJ wywpdTaQKFUTMFyMJvjVrAARhfXPDqZTckXYkxDBo2fdJ2uJikPEb2aqgoVvLXc7ncJM JF79WaXMEpmXek7SAVzwV4j7rBnvI1VsZqzCnvHEexYOHF+8uJETJBzOUh99Qabhj0Td i3kQ== X-Gm-Message-State: AOAM531FyrB6enMDLumpQZmobHA1QtfJ5PR85uRcA3OUQM3Qh20eiZq1 7K6V5dFIH7woEcr/sl45WRIYefDQ5Crg9SnF3Mdrj0Vs7EOmZNVvj29E9XgQMx3wgETm6fqigV2 KgbU5v8vIw7LK X-Received: by 2002:a05:6402:32c:: with SMTP id q12mr12910432edw.145.1611822971045; Thu, 28 Jan 2021 00:36:11 -0800 (PST) X-Google-Smtp-Source: ABdhPJzWIui6+vrd5seJH5yGW9okKQwFC1Coh5JWb1vPz0BXTa+I+8gBtJNVZkGffRelSALyWXX+kw== X-Received: by 2002:a05:6402:32c:: with SMTP id q12mr12910413edw.145.1611822970812; Thu, 28 Jan 2021 00:36:10 -0800 (PST) Received: from vitty.brq.redhat.com (g-server-2.ign.cz. [91.219.240.2]) by smtp.gmail.com with ESMTPSA id m5sm1933153eja.11.2021.01.28.00.36.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Jan 2021 00:36:10 -0800 (PST) From: Vitaly Kuznetsov To: Michael Roth , kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , linux-kernel@vger.kernel.org, Michael Roth Subject: Re: [PATCH] KVM: x86: fix CPUID entries returned by KVM_GET_CPUID2 ioctl In-Reply-To: <20210128024451.1816770-1-michael.roth@amd.com> References: <20210128024451.1816770-1-michael.roth@amd.com> Date: Thu, 28 Jan 2021 09:36:09 +0100 Message-ID: <87a6st31c6.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Michael Roth writes: > Recent commit 255cbecfe0 modified struct kvm_vcpu_arch to make > 'cpuid_entries' a pointer to an array of kvm_cpuid_entry2 entries > rather than embedding the array in the struct. KVM_SET_CPUID and > KVM_SET_CPUID2 were updated accordingly, but KVM_GET_CPUID2 was missed. > > As a result, KVM_GET_CPUID2 currently returns random fields from struct > kvm_vcpu_arch to userspace rather than the expected CPUID values. Fix > this by treating 'cpuid_entries' as a pointer when copying its > contents to userspace buffer. > > Fixes: 255cbecfe0c9 ("KVM: x86: allocate vcpu->arch.cpuid_entries dynamically") > Cc: Vitaly Kuznetsov > Signed-off-by: Michael Roth > --- > arch/x86/kvm/cpuid.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 13036cf0b912..38172ca627d3 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -321,7 +321,7 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, > if (cpuid->nent < vcpu->arch.cpuid_nent) > goto out; > r = -EFAULT; > - if (copy_to_user(entries, &vcpu->arch.cpuid_entries, > + if (copy_to_user(entries, vcpu->arch.cpuid_entries, > vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2))) > goto out; > return 0; This is embarrassing but I have a (possible) excuse: copy_to_user's argument is 'void *' so no warning was produced. Surprisingly, no test caught the breakage. Thanks for debugging and fixing! Reviewed-by: Vitaly Kuznetsov -- Vitaly