From patchwork Tue Oct 3 06:24:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13406925 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 56DFBE7542F for ; Tue, 3 Oct 2023 07:06:59 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.611995.951880 (Exim 4.92) (envelope-from ) id 1qnZUZ-0000so-Co; Tue, 03 Oct 2023 07:06:51 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 611995.951880; Tue, 03 Oct 2023 07:06:51 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qnZUZ-0000sc-7W; Tue, 03 Oct 2023 07:06:51 +0000 Received: by outflank-mailman (input) for mailman id 611995; Tue, 03 Oct 2023 07:06:49 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qnZJ1-00047B-7N for xen-devel@lists.xenproject.org; Tue, 03 Oct 2023 06:54:55 +0000 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.126]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id c0e0a640-61b9-11ee-9b0d-b553b5be7939; Tue, 03 Oct 2023 08:54:53 +0200 (CEST) Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Oct 2023 23:54:45 -0700 Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga005.fm.intel.com with ESMTP; 02 Oct 2023 23:54:45 -0700 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: c0e0a640-61b9-11ee-9b0d-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1696316093; x=1727852093; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=daicXFK30tmpTUp95RTD2ZQAe5K9xY8zuW1WSEbSaqA=; b=SiRqV/fnee4/m5V7mIYkJ8lBXaAFPrP8JRjT7c0cxyytECNbyI3XYSwz e5x6cIFFThU/LCu22A4bI9/qSOrMm4imfP7LPZGyPU8nGCSOhRDPG4eWK 1IMcUYs7pIA/8O33BBbrWvZ+Q2ZAK5CXY3m8ttFDEO6164r46aVUWYMRz no/PUkRwLtT0kd/qKaLnAEbJKeyTgErEUFyZttQ4oC1LIz2Jdw2K1ktx0 2Clo5uUyzVZhdrs6phW77s647YDQas0onIQhpiQsaAyYlqf4f7t4wQzdd U88UMjSiwijk3RjYqhKJO7q6xHL+xmzmYGxHSBJgnLcFQLVpEdlbE4xOf A==; X-IronPort-AV: E=McAfee;i="6600,9927,10851"; a="367858155" X-IronPort-AV: E=Sophos;i="6.03,196,1694761200"; d="scan'208";a="367858155" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10851"; a="1081900963" X-IronPort-AV: E=Sophos;i="6.03,196,1694761200"; d="scan'208";a="1081900963" 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 v12 21/37] x86/fred: No ESPFIX needed when FRED is enabled Date: Mon, 2 Oct 2023 23:24:42 -0700 Message-Id: <20231003062458.23552-22-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231003062458.23552-1-xin3.li@intel.com> References: <20231003062458.23552-1-xin3.li@intel.com> MIME-Version: 1.0 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 */