From patchwork Fri Jan 6 08:56:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13091180 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 595E5C3DA7A for ; Fri, 6 Jan 2023 09:22:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233287AbjAFJWD (ORCPT ); Fri, 6 Jan 2023 04:22:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233116AbjAFJU0 (ORCPT ); Fri, 6 Jan 2023 04:20:26 -0500 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04B316B5DC; Fri, 6 Jan 2023 01:20:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1672996825; x=1704532825; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=JKAIJtKpEV0pDtyUyzmPScPoDyIj7KB0n/KR4J5yOTE=; b=WEjkMrGRc5yajhWiq9Ff9gw8SaZcl5rWoOZdzEPCa9y3R3ZODp+zVVen F8eWafIChqGd4FBBAkg9SGEbdRCf6l0f65WiOc6mAaVQSaq3Jfa6aOwZM kAp1FRi+sTl75DJNSVPa3kCWqNLJrxgGrEwdqHQwbULOkwYHPvlJIl1yb LtCW6NVacIb36v2aQx5kVu1thZCxo4SRG1phaSLshFSiPaCwbdsGpjINo /fVXJPxktMxjchO9la2h1m7aeWEe469gNGWbsIuAQocN0yO8sEHvX8nz9 ftQ9hWl2iLEsyEHySoHQqvAFLCSujaEanmKghoGWWU7mEdw6vlwetHFyr Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10581"; a="322511611" X-IronPort-AV: E=Sophos;i="5.96,304,1665471600"; d="scan'208";a="322511611" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Jan 2023 01:20:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10581"; a="719139444" X-IronPort-AV: E=Sophos;i="5.96,304,1665471600"; d="scan'208";a="719139444" Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga008.fm.intel.com with ESMTP; 06 Jan 2023 01:20:17 -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 v2 26/32] x86/fred: no ESPFIX needed when FRED is enabled Date: Fri, 6 Jan 2023 00:56:11 -0800 Message-Id: <20230106085617.17248-27-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230106085617.17248-1-xin3.li@intel.com> References: <20230106085617.17248-1-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) 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 */