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=-8.6 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 3B52CC433DF for ; Mon, 22 Jun 2020 17:05:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14CEE20644 for ; Mon, 22 Jun 2020 17:05:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HK1pnyvk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730006AbgFVRFC (ORCPT ); Mon, 22 Jun 2020 13:05:02 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:48030 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729605AbgFVRE7 (ORCPT ); Mon, 22 Jun 2020 13:04:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592845497; 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=zw8XrOHkVRgeeR7QiiSEcbjjjltG1ehdscLw0b/C9c0=; b=HK1pnyvkqHnxsLGrfsqJVCnJUQGfR2HNg+QQNbW7LlAZDNwUPJriS4zqdks9x7klIWMnGc 5iig13zlfIOSl28b4c5YR78WBwAA1QTyDg1ItpuiM6QZsGXZgWv7dpa3cHdt1+gRcXTTCU wPCeMmVmlLFFh0tIf0YSjDhyLCDfkUo= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-122-B5dA4YPjNDGeLM7vej3xlg-1; Mon, 22 Jun 2020 13:04:56 -0400 X-MC-Unique: B5dA4YPjNDGeLM7vej3xlg-1 Received: by mail-wr1-f70.google.com with SMTP id a6so4859502wrq.3 for ; Mon, 22 Jun 2020 10:04:55 -0700 (PDT) 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=zw8XrOHkVRgeeR7QiiSEcbjjjltG1ehdscLw0b/C9c0=; b=Ka2O+yAilnWipqif7Sk2dse1PF4xEZrAqknepK5cSHCZZ+NAxgAWP7KBi9MCd3+/0x HAVKr06gqSjdRgJxspxCdz1Kx9B1EK+N8u1m/2JOvZfN4FI5MkTXpImQpFytM2KvW+71 ZRH5gfCdsB/zBHT9WYIfMEWAFEfvv+U8Rg28SitwRkriLDiNnWqD6UhAA5ZBOr0vaWXa nHUiGKn8Fly1WZFE/wDj5UaqmoovXh3SZSE9ciXQY1tkueEJsNqtG6bl8nKP0mA+uA34 OzS52w2McCKw4jjGOpey7qQlHEuRa7zlvz21olPp6XGoLadGukPH6CdrvG9T4cubk+dc bZig== X-Gm-Message-State: AOAM531V0qLj06RmPon6gzDAidjHKgA0wOqqfbRP/kycuv2LLisHMvCn Wqydqb6I31N1UivtnIvc9G3Ud0Tj1mYtZA565my8R2HhSEhhDFo80ZbADtTFXYfKTSMBvBUTin9 OT5oO7QoU3OyyjhqPanShT/ze X-Received: by 2002:a5d:4d4d:: with SMTP id a13mr20552792wru.252.1592845494817; Mon, 22 Jun 2020 10:04:54 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzJshRM/Q+cYn+pOyoQNIMqnZX6SUkflro/KbDFFzDy9a/O4IODCxlScxMd2GSbKua7MHQkLQ== X-Received: by 2002:a5d:4d4d:: with SMTP id a13mr20552775wru.252.1592845494559; Mon, 22 Jun 2020 10:04:54 -0700 (PDT) Received: from [192.168.10.150] ([93.56.170.5]) by smtp.gmail.com with ESMTPSA id p16sm20655190wru.27.2020.06.22.10.04.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 22 Jun 2020 10:04:53 -0700 (PDT) Subject: Re: [PATCH] KVM: x86/mmu: Avoid mixing gpa_t with gfn_t in walk_addr_generic() To: Vitaly Kuznetsov , kvm@vger.kernel.org Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , linux-kernel@vger.kernel.org References: <20200622151435.752560-1-vkuznets@redhat.com> From: Paolo Bonzini Message-ID: Date: Mon, 22 Jun 2020 19:04:53 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200622151435.752560-1-vkuznets@redhat.com> Content-Type: text/plain; charset=utf-8 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 22/06/20 17:14, Vitaly Kuznetsov wrote: > translate_gpa() returns a GPA, assigning it to 'real_gfn' seems obviously > wrong. There is no real issue because both 'gpa_t' and 'gfn_t' are u64 and > we don't use the value in 'real_gfn' as a GFN, we do > > real_gfn = gpa_to_gfn(real_gfn); > > instead. 'If you see a "buffalo" sign on an elephant's cage, do not trust > your eyes', but let's fix it for good. > > No functional change intended. > > Signed-off-by: Vitaly Kuznetsov > --- > arch/x86/kvm/mmu/paging_tmpl.h | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h > index a6d484ea110b..58234bfaca07 100644 > --- a/arch/x86/kvm/mmu/paging_tmpl.h > +++ b/arch/x86/kvm/mmu/paging_tmpl.h > @@ -360,7 +360,6 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, > ++walker->level; > > do { > - gfn_t real_gfn; > unsigned long host_addr; > > pt_access = pte_access; > @@ -375,7 +374,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, > walker->table_gfn[walker->level - 1] = table_gfn; > walker->pte_gpa[walker->level - 1] = pte_gpa; > > - real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn), > + real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn), > nested_access, > &walker->fault); > > @@ -389,12 +388,10 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, > * information to fix the exit_qualification or exit_info_1 > * fields. > */ > - if (unlikely(real_gfn == UNMAPPED_GVA)) > + if (unlikely(real_gpa == UNMAPPED_GVA)) > return 0; > > - real_gfn = gpa_to_gfn(real_gfn); > - > - host_addr = kvm_vcpu_gfn_to_hva_prot(vcpu, real_gfn, > + host_addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gpa_to_gfn(real_gpa), > &walker->pte_writable[walker->level - 1]); > if (unlikely(kvm_is_error_hva(host_addr))) > goto error; > Queued, thanks. Paolo