From patchwork Mon Apr 10 08:14:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13206186 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 C502CC76196 for ; Mon, 10 Apr 2023 08:42:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229963AbjDJImM (ORCPT ); Mon, 10 Apr 2023 04:42:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49402 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229862AbjDJIlq (ORCPT ); Mon, 10 Apr 2023 04:41:46 -0400 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 492284EED; Mon, 10 Apr 2023 01:41:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1681116072; x=1712652072; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=YTgEgmA3f1uzY8PacyZ6XmpZcGIgDW5/dB0vDrivilc=; b=TrwyM4CIrx3XOO2IddBL3Ylj0WriQKR5rwbSAhvdtu4vECZpTogOZZzo UpF+93hn+amsJf/n+GwOeqYQqsLXiHg6Ku4hvYgL/Hjaae/H+O2qUxVNW COFIhv8TQIAL/dDzcs+f+Vc0ho4TzsexxZTXEPgwqxnhD1Yxl0FYVhcjT bWaxNrY34rzMBs7zytKV+NUCWwgztpIxF+Zm6AYXL976tOQFv2bDBl5q8 mIVnvoYL2fNRGejoC3lDHs49ALi3sIOzvMuAwFjkdNdCp5QvkMnzT3bmq tgKgaKRFkS6XseWUcZ670qEk3cAeBQcb21lXfXzay1A64eFVXvoX7Ef/j Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10675"; a="342078140" X-IronPort-AV: E=Sophos;i="5.98,333,1673942400"; d="scan'208";a="342078140" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Apr 2023 01:41:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10675"; a="799436342" X-IronPort-AV: E=Sophos;i="5.98,333,1673942400"; d="scan'208";a="799436342" Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga002.fm.intel.com with ESMTP; 10 Apr 2023 01:41:07 -0700 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, jiangshanlai@gmail.com, shan.kang@intel.com Subject: [PATCH v8 25/33] x86/fred: no ESPFIX needed when FRED is enabled Date: Mon, 10 Apr 2023 01:14:30 -0700 Message-Id: <20230410081438.1750-26-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230410081438.1750-1-xin3.li@intel.com> References: <20230410081438.1750-1-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..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; + /* 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); @@ -129,6 +133,10 @@ 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 */