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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 5BDCEC433E0 for ; Mon, 8 Feb 2021 21:27:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0258964E82 for ; Mon, 8 Feb 2021 21:27:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236310AbhBHV0l (ORCPT ); Mon, 8 Feb 2021 16:26:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236715AbhBHUU0 (ORCPT ); Mon, 8 Feb 2021 15:20:26 -0500 Received: from mail-qt1-x849.google.com (mail-qt1-x849.google.com [IPv6:2607:f8b0:4864:20::849]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5197EC061788 for ; Mon, 8 Feb 2021 12:19:44 -0800 (PST) Received: by mail-qt1-x849.google.com with SMTP id v22so3192400qto.16 for ; Mon, 08 Feb 2021 12:19:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:reply-to:date:message-id:mime-version:subject:from:to:cc :content-transfer-encoding; bh=c92WD9tBjIN6OOgkPtPsSt2AYdNEujBjskOjMLRrrjI=; b=wAql08sQVg8gABzEOZq6pnXO7zG/92jQFGKp6eugdemTbEjm4IL0/Lb+dByjT9sfhN bjrPlvAKbj0oKas5ZqV4PV56jUcAei5nYjw5vJr6mG5xdB4wZk/JcHuHUioTCwKRaSdH CJzxvvBlsaMq8ms4VQHX21CJcx+1rWOKfToT9ALVbjNAX97uhylRuuwIbn7USVcM6H/V u6YsQqV0rBFRXWoILzy3Q/BkgFUMRBdVjg9XmKfKKp7sJYhoeMXuLxY9l5LbdxwGv1I7 EBzHC9tN987u4Q6Ixgn0WNBiw2/2BDxQI5v/Axz/egNhPcQU3LK2dUoaVTjSdEiOBElE 9JzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:reply-to:date:message-id:mime-version :subject:from:to:cc:content-transfer-encoding; bh=c92WD9tBjIN6OOgkPtPsSt2AYdNEujBjskOjMLRrrjI=; b=ilp1edUCSZv0P01qv/zXdxcTcXJO48mjCrAqJJ6g/C3Ac+4awF8QRghj1XEsA0Lu+Y V9tpqysM7vjx1fepChJW2FJLs+Ya+fs36aVZvDlmr36eoFOONhR6cCxvi5l8yn3aAYr8 RKgLfWBaMQQS/ipEsqTDAhMGEJbzgv5Cs3Hfg+w+Eb0MogOIuTdcHpY/Zok5LOZgvr7R kp0wWWfSpSlh4UgQJm+DMYGU8rlGIpWYQfUUZC/sSZxsmHbwsPLT0DBM4mRzJYCdZZMS O+qeP/DLhQ7G3zUxevjZIuCTHSZiPvuJdx/Z1lW5OcfU3jbqL1oZpd4aOTvGB71I1fjR ibtg== X-Gm-Message-State: AOAM530SIPGFswl9rQj6GHQhxx1wtYJl0UIdafljBAJhoCpdEJWbZ0TV 7fOg8zBomi4tsIM3ZWTJjYDi8zP3BcQ= X-Google-Smtp-Source: ABdhPJwD9shv2X/SfBHMf5rkLqrlBt/yFuFy7BTxCqki+QSLka36BUA4rdWxltPGE4NO9eUMY8h7zFBUa+M= Sender: "seanjc via sendgmr" X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:e4db:abc1:a5c0:9dbc]) (user=seanjc job=sendgmr) by 2002:a05:6214:125:: with SMTP id w5mr17608903qvs.20.1612815583538; Mon, 08 Feb 2021 12:19:43 -0800 (PST) Reply-To: Sean Christopherson Date: Mon, 8 Feb 2021 12:19:40 -0800 Message-Id: <20210208201940.1258328-1-seanjc@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.30.0.478.g8a0d178c01-goog Subject: [PATCH] KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped() From: Sean Christopherson To: Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Sean Christopherson Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use kvm_pfn_t, a.k.a. u64, for the local 'pfn' variable when retrieving a so called "remapped" hva/pfn pair. In theory, the hva could resolve to a pfn in high memory on a 32-bit kernel. This bug was inadvertantly exposed by commit bd2fae8da794 ("KVM: do not assume PTE is writable after follow_pfn"), which added an error PFN value to the mix, causing gcc to comlain about overflowing the unsigned long. arch/x86/kvm/../../../virt/kvm/kvm_main.c: In function =E2=80=98hva_to_pf= n_remapped=E2=80=99: include/linux/kvm_host.h:89:30: error: conversion from =E2=80=98long long= unsigned int=E2=80=99 to =E2=80=98long unsigned int=E2=80=99 ch= anges value from =E2=80=989218868437227405314=E2=80=99 to = =E2=80=982=E2=80=99 [-Werror=3Doverflow] 89 | #define KVM_PFN_ERR_RO_FAULT (KVM_PFN_ERR_MASK + 2) | ^ virt/kvm/kvm_main.c:1935:9: note: in expansion of macro =E2=80=98KVM_PFN_ER= R_RO_FAULT=E2=80=99 Cc: stable@vger.kernel.org Fixes: add6a0cd1c5b ("KVM: MMU: try to fix up page faults before giving up"= ) Signed-off-by: Sean Christopherson --- I don't actually know that it's possible for a remapped pfn to be a 64-bit value on a stock kernel. But, backporting a one-liner is far easier and safer than trying to audit all possible flows. :-) virt/kvm/kvm_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index ee4ac2618ec5..001b9de4e727 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1906,7 +1906,7 @@ static int hva_to_pfn_remapped(struct vm_area_struct = *vma, bool write_fault, bool *writable, kvm_pfn_t *p_pfn) { - unsigned long pfn; + kvm_pfn_t pfn; pte_t *ptep; spinlock_t *ptl; int r; --=20 2.30.0.478.g8a0d178c01-goog