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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E99CEC4332F for ; Tue, 20 Dec 2022 07:04:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233680AbiLTHED (ORCPT ); Tue, 20 Dec 2022 02:04:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233293AbiLTHBo (ORCPT ); Tue, 20 Dec 2022 02:01:44 -0500 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1B1B15FFB; Mon, 19 Dec 2022 23:01:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1671519700; x=1703055700; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=JKAIJtKpEV0pDtyUyzmPScPoDyIj7KB0n/KR4J5yOTE=; b=lxSZZffo6R2IVG4O66/yYyCQDH/75enSFundJ+3UDvT3CGtyDDogOvYO zNPFQE96TlkBVEN0xdWuV/zA9dS/kqzS3NPeSLAzhvEGm279K6fJlL6qI i5GF6fS+3UCiGEOVN2iG2YA+ZTRatjZQJwfqpJLh3VqUc9/TVdhbdGpwj ditvax7jv5oWk8b+7KXshFgF8I2O3A3Q0rqMz4+/4rxR1WsAFH4LluMr/ ekhfinBM2KUM/aX5qtCGv41Ikg5fCJ8/knfsPe3rQmvYbOraVZxRtYR44 GCN+PloMttvehJWkpc/WhKO+S1ESphp7LiQbs3ydXhVZuYDAOoAwVpoem Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10566"; a="302972137" X-IronPort-AV: E=Sophos;i="5.96,258,1665471600"; d="scan'208";a="302972137" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Dec 2022 23:01:18 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10566"; a="644326537" X-IronPort-AV: E=Sophos;i="5.96,258,1665471600"; d="scan'208";a="644326537" Received: from unknown (HELO fred..) ([172.25.112.68]) by orsmga007.jf.intel.com with ESMTP; 19 Dec 2022 23:01:18 -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: [RFC PATCH 26/32] x86/fred: no ESPFIX needed when FRED is enabled Date: Mon, 19 Dec 2022 22:36:52 -0800 Message-Id: <20221220063658.19271-27-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221220063658.19271-1-xin3.li@intel.com> References: <20221220063658.19271-1-xin3.li@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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) 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 9417d5aa7305..b594fcc0a4b7 100644 --- a/arch/x86/kernel/espfix_64.c +++ b/arch/x86/kernel/espfix_64.c @@ -116,6 +116,10 @@ void __init init_espfix_bsp(void) pgd_t *pgd; p4d_t *p4d; + /* FRED systems don't need ESPFIX */ + 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); @@ -139,6 +143,10 @@ void init_espfix_ap(int cpu) void *stack_page; pteval_t ptemask; + /* 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 */ -- 2.34.1