From patchwork Sat Sep 23 09:42:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13396688 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 3E5B7CE7A88 for ; Sat, 23 Sep 2023 10:18:11 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.607195.945572 (Exim 4.92) (envelope-from ) id 1qjzi9-0002Qp-4i; Sat, 23 Sep 2023 10:18:05 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 607195.945572; Sat, 23 Sep 2023 10:18:05 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qjzi8-0002NY-Se; Sat, 23 Sep 2023 10:18:04 +0000 Received: by outflank-mailman (input) for mailman id 607195; Sat, 23 Sep 2023 10:18:04 +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 1qjzce-0000Pn-9w for xen-devel@lists.xenproject.org; Sat, 23 Sep 2023 10:12:24 +0000 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.100]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id a4eb96da-59f9-11ee-9b0d-b553b5be7939; Sat, 23 Sep 2023 12:12:04 +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 03:11:53 -0700 Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga008.fm.intel.com with ESMTP; 23 Sep 2023 03:11:53 -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: a4eb96da-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=1695463924; x=1726999924; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=kgfFMDbJiu5q1BDcTkBjlFfGWj3DWiVrEUdh+fgWCfs=; b=hMUQY4SsiMDV1sTWLNHLkiC7dWH+tV1TUFgPqV0cizeFVKgpcjc/ox/H DxkZvzxowt2mQ2fy24L/LvOWVG8TnQu8LMwLy1lmRaCqRWed24a08mBjv +rXqMn2KsmVzmJcLmnp34AahKVqQADtJGM59sfJT8cGHrWshLSttA0a2c PW3xV2yKLWx2T0NqXYyhj0CRyr3lSHmQupbCza0LVh7+4tUVmbhNEONeT y+Y0Fb/PIfVX3QC4uNzcE5A4eDC2mSBDhWnHszQDAtCqy5XJC4raNdXZa WI2JLZJRZo6tILV/BzYiMNywjstm1EBMRZqKNXFdwUlmANDq/FLN7N6zq g==; X-IronPort-AV: E=McAfee;i="6600,9927,10841"; a="447492498" X-IronPort-AV: E=Sophos;i="6.03,171,1694761200"; d="scan'208";a="447492498" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10841"; a="813388236" X-IronPort-AV: E=Sophos;i="6.03,171,1694761200"; d="scan'208";a="813388236" 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 35/37] x86/syscall: Split IDT syscall setup code into idt_syscall_init() Date: Sat, 23 Sep 2023 02:42:10 -0700 Message-Id: <20230923094212.26520-36-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 Because FRED uses the ring 3 FRED entrypoint for SYSCALL and SYSENTER and ERETU is the only legit instruction to return to ring 3, there is NO need to setup SYSCALL and SYSENTER MSRs for FRED, except the IA32_STAR MSR. Split IDT syscall setup code into idt_syscall_init() to make it easy to skip syscall setup code when FRED is enabled. Suggested-by: Thomas Gleixner Tested-by: Shan Kang Signed-off-by: Xin Li --- arch/x86/kernel/cpu/common.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 20bbedbf6dcb..2ee4e7b597a3 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2071,10 +2071,8 @@ static void wrmsrl_cstar(unsigned long val) wrmsrl(MSR_CSTAR, val); } -/* May not be marked __init: used by software suspend */ -void syscall_init(void) +static inline void idt_syscall_init(void) { - wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64); if (ia32_enabled()) { @@ -2108,6 +2106,15 @@ void syscall_init(void) X86_EFLAGS_AC|X86_EFLAGS_ID); } +/* May not be marked __init: used by software suspend */ +void syscall_init(void) +{ + /* The default user and kernel segments */ + wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS); + + idt_syscall_init(); +} + #else /* CONFIG_X86_64 */ #ifdef CONFIG_STACKPROTECTOR