From patchwork Wed Nov 11 18:53:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Gardon X-Patchwork-Id: 11898335 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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, 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_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 CAAB9C388F9 for ; Wed, 11 Nov 2020 18:53:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 627E0206FB for ; Wed, 11 Nov 2020 18:53:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="kK51WkYo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727635AbgKKSxn (ORCPT ); Wed, 11 Nov 2020 13:53:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725949AbgKKSxm (ORCPT ); Wed, 11 Nov 2020 13:53:42 -0500 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80A6FC0613D1 for ; Wed, 11 Nov 2020 10:53:42 -0800 (PST) Received: by mail-pj1-x104a.google.com with SMTP id t15so1260096pja.7 for ; Wed, 11 Nov 2020 10:53:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:message-id:mime-version:subject:from:to:cc; bh=93R4ztQrLrDF9Ja7P3toIKUvpq9Mkw15Zf+bh5c6Tqo=; b=kK51WkYoFHiSWND2/+N+C4Ova1zafjAVM+MPR0hpWwVY8W6VovOfLNmIiMynognenH lbj/HnGi8LUypoLkUvvq6ifdmaKSM7Qs5KY8OLvuNSHqi93xn9P6OKqDth56mfLf7TmS eTy6XVOeyZYgAtmx4jHnLmdF44tZnyR7Y37vDyXD8JbUe+YWpWxdIFOY2Nm8WnVKjlrZ mxOlGUs7o2Q964Dlth1cEweUi0t1TPbzd6pUE+KsV14NikSdbNfPu+/9c1+67WbwQh0t up5tbY5R9KY1/3ZqfWU+oDjfpEZZf3nt8OrukS3kW8t8SAHkHMKBe8JkEeeJE8heHb7y 6zVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:message-id:mime-version:subject:from :to:cc; bh=93R4ztQrLrDF9Ja7P3toIKUvpq9Mkw15Zf+bh5c6Tqo=; b=eFh7sMLcpSfXgMWWZ+nxA2n85HEoh2RYfmx/19TENlVneVZ404eC0QMqp6ZkrU/I5C HVTeQCUQ0M+hQ8/of+IX2GcpPLNC3AZGVKu3LyJg/y04WQSkq3akz8dUXomRfaQSQhyN stQ57MhpiJbijYyPnB8yUNv/tUamw+sFqr7t70IZsSdb5GnpiBdfMMb3vifhwAf5nKKa TtjLhQKz+adt5rGMPaNpVgi376qZaoCLr3IG+AmQn/kowIU61dTB4HcSiBfI5sjntwJn z5EoU2FPp7AS7Dl0GE1vrKCOOGWzJpLFmkNkG/0qn1FHg2KLSaW4oLCXolEbb8VXQvrv vOmg== X-Gm-Message-State: AOAM532tyXEJs0sIuKlEcjxpKFPTARk2fqWGqV76q9x/4a1KtCx1oh6T nOMOaf53wDzKskvTbLHWkTqW9ePc5v9t X-Google-Smtp-Source: ABdhPJyl7J/4ZMYI6a1D98WFOkbXOBJ8G/8pul2PYv3oklRs7dNvgDUFi0coDy0Z5skyieCqVo68nE6HtM2h Sender: "bgardon via sendgmr" X-Received: from bgardon.sea.corp.google.com ([2620:15c:100:202:f693:9fff:fef4:a293]) (user=bgardon job=sendgmr) by 2002:a17:902:bc46:b029:d6:d98a:1a68 with SMTP id t6-20020a170902bc46b02900d6d98a1a68mr10718919plz.63.1605120821929; Wed, 11 Nov 2020 10:53:41 -0800 (PST) Date: Wed, 11 Nov 2020 10:53:37 -0800 Message-Id: <20201111185337.1237383-1-bgardon@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.29.2.222.g5d2a92d10f8-goog Subject: [PATCH] kvm: x86/mmu: Fix is_tdp_mmu_check when using PAE From: Ben Gardon To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Sean Christopherson , Peter Shier , Jim Mattson , Zdenek Kaspar , Ben Gardon Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org When PAE is in use, the root_hpa will not have a shadow page assoicated with it. In this case the kernel will crash with a NULL pointer dereference. Add checks to ensure is_tdp_mmu_root works as intended even when using PAE. Tested: compiles Fixes: 02c00b3a2f7e ("kvm: x86/mmu: Allocate and free TDP MMU roots") Reported-by: Zdenek Kaspar Signed-off-by: Ben Gardon Tested-by: Zdenek Kaspar --- arch/x86/kvm/mmu/tdp_mmu.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 27e381c9da6c..13013f4d98ad 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -49,8 +49,18 @@ bool is_tdp_mmu_root(struct kvm *kvm, hpa_t hpa) { struct kvm_mmu_page *sp; + if (WARN_ON(!VALID_PAGE(hpa))) + return false; + sp = to_shadow_page(hpa); + /* + * If this VM is being run with PAE, the TDP MMU will not be enabled + * and the root HPA will not have a shadow page associated with it. + */ + if (!sp) + return false; + return sp->tdp_mmu_page && sp->root_count; }