From patchwork Thu Sep 14 04:47:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13384533 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 1BF99EDE985 for ; Thu, 14 Sep 2023 05:19:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235114AbjINFTq (ORCPT ); Thu, 14 Sep 2023 01:19:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235124AbjINFT3 (ORCPT ); Thu, 14 Sep 2023 01:19:29 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF25E1BD4; Wed, 13 Sep 2023 22:19:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1694668761; x=1726204761; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=daicXFK30tmpTUp95RTD2ZQAe5K9xY8zuW1WSEbSaqA=; b=c91nZfFofOZKNdKrmUhQGL3nbvAwZhFXJyaEsMh+EWgPagnwj67J7ibY AmDAhHQG5z+A5fZxH6K6e89v7f3v62GSgMsjwN4vrOoIFdKrTaE3sTROY g6ncn/XW0XPwrolGq8g3y/2qCSaZLgV68/tjYeAHzaxhjqwkKHq+hH1tf GdopUPAphxt+gLtd5p6NIII77ZJHAz9DRqCaagaqCp9UOdyfooS6m/UHU Hhq6ev4aSvWBYPJn3k2/lEwAdBOHGR9SQxIwSGMU4vE0EsCVr/b8DgdSh LyYc5J+4G8Pe8XMcudmF838Ycq8Uz/Haeed/n9HqxjS3roqG5H1T1Egxu Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10832"; a="382661341" X-IronPort-AV: E=Sophos;i="6.02,145,1688454000"; d="scan'208";a="382661341" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Sep 2023 22:17:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10832"; a="779488802" X-IronPort-AV: E=Sophos;i="6.02,145,1688454000"; d="scan'208";a="779488802" Received: from unknown (HELO fred..) ([172.25.112.68]) by orsmga001.jf.intel.com with ESMTP; 13 Sep 2023 22:17:39 -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 Subject: [PATCH v10 21/38] x86/fred: No ESPFIX needed when FRED is enabled Date: Wed, 13 Sep 2023 21:47:48 -0700 Message-Id: <20230914044805.301390-22-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230914044805.301390-1-xin3.li@intel.com> References: <20230914044805.301390-1-xin3.li@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-edac@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 */