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=-26.4 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_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 94257C49EA6 for ; Fri, 25 Jun 2021 00:19:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65BFC613C9 for ; Fri, 25 Jun 2021 00:19:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232957AbhFYAVV (ORCPT ); Thu, 24 Jun 2021 20:21:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232933AbhFYAVU (ORCPT ); Thu, 24 Jun 2021 20:21:20 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D2AFC061756 for ; Thu, 24 Jun 2021 17:18:59 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id l12-20020a25ad4c0000b029055444b6e99bso1708899ybe.5 for ; Thu, 24 Jun 2021 17:18:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=reply-to:date:message-id:mime-version:subject:from:to:cc; bh=6fjzUtku/PtRujaCxglb2g16yONAmo5V2De3zOjXjoc=; b=qpcFFW0RGwSColAnhc/3Iy3uEck2HZTjVCBNLgz4JdCOAAd/9YXF7I2xAPgKIazivh 4AJPvqK51r9HiW1ZqGa/sHvXsLYOoerJv7r0D33alsqvPpjqtMIJfLgDiTSOa1leGXSy BcjwmikeAthbKD6Mwe9T/XGoPNDeWXWg3jwqFfVpta6+1b0cQpwJsVGAhT5+bk8z+gpt sczX8FKOW044HHSuLV9VdbfjjE8Qw3xVIne4RypNx5bRpbF+2mJUbUWXq1fojtEPOL4l a8B1JTKN4F4bEbkUiByeI+c05DTMgIuI/01b+5vEn/9I24QLogLql9GqAFYaxMll/CcL GcFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:reply-to:date:message-id:mime-version:subject :from:to:cc; bh=6fjzUtku/PtRujaCxglb2g16yONAmo5V2De3zOjXjoc=; b=bnnn2KV9KSI4lwsa3d9pBx75RD/tduQj/gh2j7WUwbllWNna9Syf5viYEQTifCWeQ2 Uyj3Wr9DdVwu6ToEGpmU+hUqwXd5tJ9P1OJO1uvRROLMrR4+l4iZp6faF+MK3fPaUBwN 7jHZ2ZfychRrYsiEsepfC/q30KitDjinYd8AaNZD+jYTEFvzsPrrcL68Z7DHH0WANzi4 QTE8nljslDD9FWewzUsdT3nkps2bO1ha2L07yrrGR3zABNWaDBvIkx5TBT9avpcm14We OC/ou+rx/Wi9zBDaigdTJK6DUvU1qtJO0axAXiemM5h2DJjvUZJfdfSLfPKNOOP3WS0Y T9lA== X-Gm-Message-State: AOAM531E/FLiqXTX/2cr3X1ch6OvySUB185tHTCRKDx5o4zcCIAAz1Pd fHhesMyL+wH23ZHgwBxm9Wr5qcZOBas= X-Google-Smtp-Source: ABdhPJymk4k2ITDoivLr/PI7hmMnTloV0UNdYLa/stFT1YkFD9JtUH1c4jIUTrrEu0OrsZQOJWxIjbc4PAI= X-Received: from seanjc798194.pdx.corp.google.com ([2620:15c:f:10:7c83:7704:b3b6:754c]) (user=seanjc job=sendgmr) by 2002:a25:74cc:: with SMTP id p195mr9042062ybc.109.1624580338507; Thu, 24 Jun 2021 17:18:58 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 24 Jun 2021 17:18:53 -0700 Message-Id: <20210625001853.318148-1-seanjc@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.32.0.93.g670b81a890-goog Subject: [PATCH] Revert "KVM: x86: WARN and reject loading KVM if NX is supported but not enabled" From: Sean Christopherson To: Paolo Bonzini Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Let KVM load if EFER.NX=0 even if NX is supported, the analysis and testing (or lack thereof) for the non-PAE host case was garbage. If the kernel won't be using PAE paging, .Ldefault_entry in head_32.S skips over the entire EFER sequence. Hopefully that can be changed in the future to allow KVM to require EFER.NX, but the motivation behind KVM's requirement isn't yet merged. Reverting and revisiting the mess at a later date is by far the safest approach. This reverts commit 8bbed95d2cb6e5de8a342d761a89b0a04faed7be. Fixes: 8bbed95d2cb6 ("KVM: x86: WARN and reject loading KVM if NX is supported but not enabled") Signed-off-by: Sean Christopherson --- Hopefully it's not too late to just drop the original patch... arch/x86/kvm/x86.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4a597aafe637..1cc02a3685d0 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10981,9 +10981,6 @@ 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); -- 2.32.0.93.g670b81a890-goog