From patchwork Sat Sep 23 09:41:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13396619 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 69515CE7A8C for ; Sat, 23 Sep 2023 10:12:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231661AbjIWKMV (ORCPT ); Sat, 23 Sep 2023 06:12:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231474AbjIWKL5 (ORCPT ); Sat, 23 Sep 2023 06:11:57 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C7771BD; Sat, 23 Sep 2023 03:11:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695463908; x=1726999908; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=daicXFK30tmpTUp95RTD2ZQAe5K9xY8zuW1WSEbSaqA=; b=RF50qkSpXHkHvKH70GYJdehu6SU3Tclu7ny+agEjlzZReORO8M5gsxbV 8jDchmx4WmEn33UhCqsX4CjoBXYgdfBdjAmS+HMFbfDBCFPV7eWDoMkGv q/7eEWUDKWJdYTRbV8hzQ2Iz+5sDgKxf+Wv6rMjHbYhdZUa5fWmNndX4Q eXYORjBSws+aAHGQOyrCwmPQ+0yRqv4Rifm2RXtDgJT+SBBlUF4BrgT9f 68LAUNQbSN9Kiu5LqsIlG8OLU6bawp61JmyjAoGzoX/VMBSsWIzUgyZSf WVba+/zSdaJoJcfXH3TAgiA8+siEh/zsn4Rc1T2qwfGaMtmo+rsOhFdBP g==; X-IronPort-AV: E=McAfee;i="6600,9927,10841"; a="447492326" X-IronPort-AV: E=Sophos;i="6.03,171,1694761200"; d="scan'208";a="447492326" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2023 03:11:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10841"; a="813388176" X-IronPort-AV: E=Sophos;i="6.03,171,1694761200"; d="scan'208";a="813388176" Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga008.fm.intel.com with ESMTP; 23 Sep 2023 03:11:46 -0700 From: Xin Li To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, pbonzini@redhat.com, seanjc@google.com, peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com, mhiramat@kernel.org, andrew.cooper3@citrix.com, jiangshanlai@gmail.com, nik.borisov@suse.com Subject: [PATCH v11 21/37] x86/fred: No ESPFIX needed when FRED is enabled Date: Sat, 23 Sep 2023 02:41:56 -0700 Message-Id: <20230923094212.26520-22-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230923094212.26520-1-xin3.li@intel.com> References: <20230923094212.26520-1-xin3.li@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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..6726e0473d0b 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; + /* FRED systems always restore the full value of %rsp */ + if (cpu_feature_enabled(X86_FEATURE_FRED)) + return; + /* Install the espfix pud into the kernel page directory */ pgd = &init_top_pgt[pgd_index(ESPFIX_BASE_ADDR)]; p4d = p4d_alloc(&init_mm, pgd, ESPFIX_BASE_ADDR); @@ -129,6 +133,10 @@ void init_espfix_ap(int cpu) void *stack_page; pteval_t ptemask; + /* FRED systems always restore the full value of %rsp */ + 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 */