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=-23.4 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_IN_DEF_DKIM_WL 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 53697C49EA6 for ; Thu, 24 Jun 2021 22:33:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E896610A0 for ; Thu, 24 Jun 2021 22:33:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232869AbhFXWgO (ORCPT ); Thu, 24 Jun 2021 18:36:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229643AbhFXWgN (ORCPT ); Thu, 24 Jun 2021 18:36:13 -0400 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F17B9C061756 for ; Thu, 24 Jun 2021 15:33:53 -0700 (PDT) Received: by mail-pj1-x102a.google.com with SMTP id bb20so4337360pjb.3 for ; Thu, 24 Jun 2021 15:33:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=PHR4j2h2rOVtlrAiNcYi9OQO+yd/4fA9sq0SL3O5RKQ=; b=iu8gCBRuL6cV7l7ZrtAdMuWYVJ92vky7nyiGSX48wVr5Ec5e+8hcrFzCzXJQWfnh1P QZlfYzkXDmAU6fmWcMEpY6Bt6T+fBl+Vd11LAdDI0btDxgSfLCRndKuWWdMY4ayTyoBt xbjSMLPC9I3csBXIoDN9Utuqxb6mcd9lFhzL54XtDH/g+tTgag2xzYcIof82gTur1RRX 37W21PH6vpi3G1L5rZffK5HCAksBK14sZd2QUrJxJpYAqDYYdrDdBWZuEtpWbWovUhAu mkFXN59LHVWORovr80eYj9120eo1L04z1dDawqg/v1fxJDcaFUogpe0SBROhHPtJz2iX O26g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=PHR4j2h2rOVtlrAiNcYi9OQO+yd/4fA9sq0SL3O5RKQ=; b=qHMeRhAcYvkLXuvc0KSVMpienirGBIrTsKxeXljbEO75b672SVnAQPj2H8CtykJmLi 9N2f60NGu14JZExBcfE8W8AgZK0lscGAZhr7xYn+W1Gw+/BWZJkEgzhXfyTpYNh5xOiB UMxOYmWIN1CIXblD7pjSlLehMq9cmLEk2YkFFw5VBikD4ZVS1OUE9xVWTQTxHC9pqFJA FApMTorbTe8lMa7+2sbklJY908K1SnGR5i4lCjCZEw0LSPFYwwbnhit6VlUhQuPvnqqa e5aJZhXacfTDxvFmqEeJc+kmKRIVBWjeKA4OoX/l/OoIlDy2auXJdu3zDY00rzNbygdu mn5w== X-Gm-Message-State: AOAM5327l64rfokc5EfoVGrHKU/8FPQyeqxzr7+bLLLKfn0ryWufbGwm hx/LPhj7riWQ5pmOPaENh/hn9Q== X-Google-Smtp-Source: ABdhPJzbPpNFsgn7eKZFndlwq1QREGtEsWkKYJrDYzmLY4T/ngRcz014t6Au6rVpVGJ/wrI9Ztcj0g== X-Received: by 2002:a17:90b:1191:: with SMTP id gk17mr7609490pjb.95.1624574033291; Thu, 24 Jun 2021 15:33:53 -0700 (PDT) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id h22sm3397732pju.22.2021.06.24.15.33.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Jun 2021 15:33:52 -0700 (PDT) Date: Thu, 24 Jun 2021 22:33:49 +0000 From: Sean Christopherson To: Paolo Bonzini , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] KVM: x86: WARN and reject loading KVM if NX is supported but not enabled Message-ID: References: <20210615164535.2146172-1-seanjc@google.com> <20210615164535.2146172-4-seanjc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210615164535.2146172-4-seanjc@google.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Jun 15, 2021, Sean Christopherson wrote: > WARN if NX is reported as supported but not enabled in EFER. All flavors > of the kernel, including non-PAE 32-bit kernels, set EFER.NX=1 if NX is > supported, even if NX usage is disable via kernel command line. Ugh, I misread .Ldefault_entry in head_32.S, it skips over the entire EFER code if PAE=0. Apparently I didn't test this with non-PAE paging and EPT? Paolo, I'll send a revert since it's in kvm/next, but even better would be if you can drop the patch :-) Lucky for me you didn't pick up patch 4/4 that depends on this... I'll revisit this mess in a few weeks. > on NX being enabled if it's supported, e.g. KVM will generate illegal NPT > entries if nx_huge_pages is enabled and NX is supported but not enabled. > > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/x86.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index acc28473dec7..1f6595df45de 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -10981,6 +10981,9 @@ int kvm_arch_hardware_setup(void *opaque) > int r; > > rdmsrl_safe(MSR_EFER, &host_efer); > + if (WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_NX) && > + !(host_efer & EFER_NX))) > + return -EIO; > > if (boot_cpu_has(X86_FEATURE_XSAVES)) > rdmsrl(MSR_IA32_XSS, host_xss); > -- > 2.32.0.272.g935e593368-goog >