From nobody Sat Apr 11 07:07:34 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D04E8C7EE2F for ; Thu, 2 Mar 2023 05:52:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230015AbjCBFwy (ORCPT ); Thu, 2 Mar 2023 00:52:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230003AbjCBFwT (ORCPT ); Thu, 2 Mar 2023 00:52:19 -0500 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25EA351F9E; Wed, 1 Mar 2023 21:51:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1677736283; x=1709272283; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=YTgEgmA3f1uzY8PacyZ6XmpZcGIgDW5/dB0vDrivilc=; b=HOuaorGBemCaZyBXmXxjQ3em0xKDFzaWI+0p/xIwjLYNrEyXINVbyvd/ V2k0p2wWGDZ909PSei7r4WXqq5jbtyCz3MDF+BxALl4p36ltvJ9/+iu0V 222gcU1HdYCOGedxtzc9L4AHP/c6Z+vEbRMXMg9dY2llo1hTI3cFLgTiM lnC8Ijk/rlC1fqD+z6j/zNgrO92pabtw6ZoHzdn+wpKm5oUhTB2Z0YGVT dyO20vr4uZQnB0sHpNUnezsUs1kbsFH+nuR+aPzCYlPj7ba4X+U416u/W 0aAdRHGolS0+xHULy4k9NyEuUjQUJGILmIyBhJLBYOF3007R7YDKZ/awP g==; X-IronPort-AV: E=McAfee;i="6500,9779,10636"; a="420887268" X-IronPort-AV: E=Sophos;i="5.98,226,1673942400"; d="scan'208";a="420887268" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Mar 2023 21:50:52 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10636"; a="920530958" X-IronPort-AV: E=Sophos;i="5.98,226,1673942400"; d="scan'208";a="920530958" Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga006.fm.intel.com with ESMTP; 01 Mar 2023 21:50:50 -0800 From: Xin Li To: linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, andrew.cooper3@citrix.com, seanjc@google.com, pbonzini@redhat.com, ravi.v.shankar@intel.com Subject: [PATCH v4 26/34] x86/fred: no ESPFIX needed when FRED is enabled Date: Wed, 1 Mar 2023 21:25:03 -0800 Message-Id: <20230302052511.1918-27-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230302052511.1918-1-xin3.li@intel.com> References: <20230302052511.1918-1-xin3.li@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "H. Peter Anvin (Intel)" Because FRED always restores the full value of %rsp, ESPFIX is no longer needed when it's enabled. Signed-off-by: H. Peter Anvin (Intel) Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/kernel/espfix_64.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c index 16f9814c9be0..48d133a54f45 100644 --- a/arch/x86/kernel/espfix_64.c +++ b/arch/x86/kernel/espfix_64.c @@ -106,6 +106,10 @@ void __init init_espfix_bsp(void) pgd_t *pgd; p4d_t *p4d; =20 + /* FRED systems don't need ESPFIX */ + if (cpu_feature_enabled(X86_FEATURE_FRED)) + return; + /* Install the espfix pud into the kernel page directory */ pgd =3D &init_top_pgt[pgd_index(ESPFIX_BASE_ADDR)]; p4d =3D p4d_alloc(&init_mm, pgd, ESPFIX_BASE_ADDR); @@ -129,6 +133,10 @@ void init_espfix_ap(int cpu) void *stack_page; pteval_t ptemask; =20 + /* FRED systems don't need ESPFIX */ + if (cpu_feature_enabled(X86_FEATURE_FRED)) + return; + /* We only have to do this once... */ if (likely(per_cpu(espfix_stack, cpu))) return; /* Already initialized */ --=20 2.34.1