From patchwork Tue Dec 5 10:50:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Li, Xin3" X-Patchwork-Id: 13480066 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 08148C4167B for ; Tue, 5 Dec 2023 11:28:46 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.647614.1011040 (Exim 4.92) (envelope-from ) id 1rATbR-0000VY-1h; Tue, 05 Dec 2023 11:28:37 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 647614.1011040; Tue, 05 Dec 2023 11:28:37 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1rATbQ-0000VR-VK; Tue, 05 Dec 2023 11:28:36 +0000 Received: by outflank-mailman (input) for mailman id 647614; Tue, 05 Dec 2023 11:28:36 +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 1rATUt-0003dP-VV for xen-devel@lists.xenproject.org; Tue, 05 Dec 2023 11:21:51 +0000 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 751beeef-9360-11ee-9b0f-b553b5be7939; Tue, 05 Dec 2023 12:21:38 +0100 (CET) Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Dec 2023 03:21:27 -0800 Received: from unknown (HELO fred..) ([172.25.112.68]) by fmsmga006.fm.intel.com with ESMTP; 05 Dec 2023 03:21:26 -0800 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: 751beeef-9360-11ee-9b0f-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1701775300; x=1733311300; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=UVhP7f+75Ax+FxvYCkHZURx9ZVwCqbLITZRLMgz0Nr0=; b=GmWxsUBBhd1slAkZzx9RFtv19DACoJq+oMKuRy+URTqiorKHVoMS8zTH pw0eXCQT80r08CEVTOr///1FLP21QkE4YSScdhOb5tDOVlZtbyOxyc0vp 69Ek2F/UhX8aMq4JLJVw3TEMtveqEGVnSCQyYcwCi/aQKVS2BMivFlUF1 DypkB2swzJUoeTq9Mk3++rONf6TkmuCjd2kgqkFqtin/IAPTehA/2KQqE l6RCrPw3tFtQZNWbIJhs+ndJZu+blfjQz0PVsikKyIF6DVpJdABw1HWDM SOzLw8zYWbWwLa9ELs4TAZs4XMpz6TIqX9nhNAzl610rsMlIBbPjOhpWs w==; X-IronPort-AV: E=McAfee;i="6600,9927,10914"; a="942706" X-IronPort-AV: E=Sophos;i="6.04,252,1695711600"; d="scan'208";a="942706" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10914"; a="1018193015" X-IronPort-AV: E=Sophos;i="6.04,252,1695711600"; d="scan'208";a="1018193015" 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, shan.kang@intel.com Subject: [PATCH v13 33/35] x86/syscall: Split IDT syscall setup code into idt_syscall_init() Date: Tue, 5 Dec 2023 02:50:22 -0800 Message-ID: <20231205105030.8698-34-xin3.li@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231205105030.8698-1-xin3.li@intel.com> References: <20231205105030.8698-1-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 132f41f7c27f..9a075792e275 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2076,10 +2076,8 @@ 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()) { @@ -2113,6 +2111,15 @@ 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