From patchwork Sat Sep 23 09:41:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13396672 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 A62A4CE7A88 for ; Sat, 23 Sep 2023 10:16:36 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.607137.945409 (Exim 4.92) (envelope-from ) id 1qjzgb-0000Dr-Q0; Sat, 23 Sep 2023 10:16:29 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 607137.945409; Sat, 23 Sep 2023 10:16:29 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qjzgb-0000CC-DX; Sat, 23 Sep 2023 10:16:29 +0000 Received: by outflank-mailman (input) for mailman id 607137; Sat, 23 Sep 2023 10:16:28 +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 1qjzcL-0000Pn-7f for xen-devel@lists.xenproject.org; Sat, 23 Sep 2023 10:12:05 +0000 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.100]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 9f8e696d-59f9-11ee-9b0d-b553b5be7939; Sat, 23 Sep 2023 12:11:56 +0200 (CEST) Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Sep 2023 03:11:46 -0700 Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga008.fm.intel.com with ESMTP; 23 Sep 2023 03:11:46 -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: 9f8e696d-59f9-11ee-9b0d-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695463916; x=1726999916; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=daicXFK30tmpTUp95RTD2ZQAe5K9xY8zuW1WSEbSaqA=; b=bTvLYvEL753J6F+eT7JbN/mdzjZC7Rq5LQCQFkvCCAqkes4P/hwHR1+B UleqtudmL/IKwrD84g+JSVa8A7tKh1UUyKR9D1NsCeQPb6z5VfuCzNAir vu4aKHpjix2pcX4cIrCmk2aQRYy/QoeIP/vziv4mxEwVgvGrvjBJkIzEd UHcalqfL0TISgwSVAFQS0SU0I8ELlV1AdEqbOuF7KSe9Bkc4tZvdySSHI jbWhD3K/dXlzVBirVP+nnQMzVYIr2KJ6NasNuM4tySXYLY3y9uPO8AFja 453EWHmSouN3jYga5/cLvw7na2DafSB6h30p1IOPp3Bd+UJRuOp/9Inn3 g==; X-IronPort-AV: E=McAfee;i="6600,9927,10841"; a="447492327" X-IronPort-AV: E=Sophos;i="6.03,171,1694761200"; d="scan'208";a="447492327" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10841"; a="813388176" X-IronPort-AV: E=Sophos;i="6.03,171,1694761200"; d="scan'208";a="813388176" 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 v11 21/37] x86/fred: No ESPFIX needed when FRED is enabled Date: Sat, 23 Sep 2023 02:41:56 -0700 Message-Id: <20230923094212.26520-22-xin3.li@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230923094212.26520-1-xin3.li@intel.com> References: <20230923094212.26520-1-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 */