From mboxrd@z Thu Jan 1 00:00:00 1970 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 F07B8C433FE for ; Fri, 18 Feb 2022 16:18:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237773AbiBRQTL (ORCPT ); Fri, 18 Feb 2022 11:19:11 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:44008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237643AbiBRQR4 (ORCPT ); Fri, 18 Feb 2022 11:17:56 -0500 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 008413A5E6 for ; Fri, 18 Feb 2022 08:17:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1645201047; x=1676737047; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=C/Kr5OtLyLFJ8JIEjNyBn5AW++nQARb4Poi2KZHPrbc=; b=DCSQRPyolIoJMHOxx9IIBD1kdWDgZU1CmbZFNum895//uBKeKGxunvsT waj0Ktn18X2jRef1y3aiYEeT/76abaBc0COepu79FaBBVoggNAK3xzrPv tKwB5hzcLg6Hvn8RkksGSO4j1uKoicguLZpk3uCGCKgsYRyrXWP367gtX ID5AZb8M34anoUxesDyeBzOAH3BGgum0adYE8+pMnfCetnlz9dva6fIpA AEV/A+L+eM9u8juf4s6TKjDbka+EqSu3w+gx2o3YTP6ot8po0vRZRXadq WgPLmbPk9eVvNMLzM1t1Y/1wq56xK1XMy4V4McSMO5+dnpicIO3HZ6lIq w==; X-IronPort-AV: E=McAfee;i="6200,9189,10261"; a="238559747" X-IronPort-AV: E=Sophos;i="5.88,379,1635231600"; d="scan'208";a="238559747" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Feb 2022 08:17:26 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,379,1635231600"; d="scan'208";a="546333157" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga008.jf.intel.com with ESMTP; 18 Feb 2022 08:17:20 -0800 Received: by black.fi.intel.com (Postfix, from userid 1000) id EBEF2B2F; Fri, 18 Feb 2022 18:17:22 +0200 (EET) From: "Kirill A. Shutemov" To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@intel.com, luto@kernel.org, peterz@infradead.org Cc: sathyanarayanan.kuppuswamy@linux.intel.com, aarcange@redhat.com, ak@linux.intel.com, dan.j.williams@intel.com, david@redhat.com, hpa@zytor.com, jgross@suse.com, jmattson@google.com, joro@8bytes.org, jpoimboe@redhat.com, knsathya@kernel.org, pbonzini@redhat.com, sdeep@vmware.com, seanjc@google.com, tony.luck@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, x86@kernel.org, linux-kernel@vger.kernel.org, "Kirill A . Shutemov" Subject: [PATCHv3 19/32] x86/tdx: Handle early boot port I/O Date: Fri, 18 Feb 2022 19:17:05 +0300 Message-Id: <20220218161718.67148-20-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220218161718.67148-1-kirill.shutemov@linux.intel.com> References: <20220218161718.67148-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andi Kleen TDX guests cannot do port I/O directly. The TDX module triggers a #VE exception to let the guest kernel emulate port I/O by converting them into TDCALLs to call the host. But before IDT handlers are set up, port I/O cannot be emulated using normal kernel #VE handlers. To support the #VE-based emulation during this boot window, add a minimal early #VE handler support in early exception handlers. This is similar to what AMD SEV does. This is mainly to support earlyprintk's serial driver, as well as potentially the VGA driver. The early handler only supports I/O-related #VE exceptions. Unhandled or failed exceptions will be handled via early_fixup_exceptions() (like normal exception failures). Signed-off-by: Andi Kleen Reviewed-by: Dan Williams Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Kirill A. Shutemov Reviewed-by: Thomas Gleixner --- arch/x86/coco/tdx.c | 16 ++++++++++++++++ arch/x86/include/asm/tdx.h | 4 ++++ arch/x86/kernel/head64.c | 3 +++ 3 files changed, 23 insertions(+) diff --git a/arch/x86/coco/tdx.c b/arch/x86/coco/tdx.c index e3693d0494a7..d23d389124a1 100644 --- a/arch/x86/coco/tdx.c +++ b/arch/x86/coco/tdx.c @@ -344,6 +344,22 @@ static bool handle_io(struct pt_regs *regs, u32 exit_qual) return ret; } +/* + * Early #VE exception handler. Only handles a subset of port I/O. + * Intended only for earlyprintk. If failed, return false. + */ +__init bool tdx_early_handle_ve(struct pt_regs *regs) +{ + struct ve_info ve; + + tdx_get_ve_info(&ve); + + if (ve.exit_reason != EXIT_REASON_IO_INSTRUCTION) + return false; + + return handle_io(regs, ve.exit_qual); +} + void tdx_get_ve_info(struct ve_info *ve) { struct tdx_module_output out; diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index 54803cb6ccf5..ba0f8c2b185c 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -56,11 +56,15 @@ bool tdx_handle_virt_exception(struct pt_regs *regs, struct ve_info *ve); void tdx_safe_halt(void); +bool tdx_early_handle_ve(struct pt_regs *regs); + #else static inline void tdx_early_init(void) { }; static inline void tdx_safe_halt(void) { }; +static inline bool tdx_early_handle_ve(struct pt_regs *regs) { return false; } + #endif /* CONFIG_INTEL_TDX_GUEST */ #endif /* !__ASSEMBLY__ */ diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 6dff50c3edd6..ecbf50e5b8e0 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -417,6 +417,9 @@ void __init do_early_exception(struct pt_regs *regs, int trapnr) trapnr == X86_TRAP_VC && handle_vc_boot_ghcb(regs)) return; + if (trapnr == X86_TRAP_VE && tdx_early_handle_ve(regs)) + return; + early_fixup_exception(regs, trapnr); } -- 2.34.1