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 B0747C433F5 for ; Wed, 16 Mar 2022 02:11:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353142AbiCPCMh (ORCPT ); Tue, 15 Mar 2022 22:12:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47210 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352872AbiCPCL0 (ORCPT ); Tue, 15 Mar 2022 22:11:26 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75CC95EBC0 for ; Tue, 15 Mar 2022 19:10:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1647396612; x=1678932612; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=xOctABj2qmFel0C+H1oeMX85GemMOEwhkgwc+CqJ4XQ=; b=Bam2qTMEfCPM7f5rlKWSsArOIwcvPDeEekIknfPOtzIjwjoVu0e6OWoK fT1d4z6he1tInDnBlRiGkeDut2qegHTv/sDSkplvGpxpVuIYcQMVtnDDv G0/iI1V65QBNEeq3iivo8hGXHgPNzWPemmNb/O1fuv81c/7hKuOe3X0Ua VhS7ZL2va1BSK3cXf3LCIAUfFAJ/PPOu0CCdrWHbMMbP938vBc6O4nRXY i7AvgPU5mMM5B2RscMRxMwjZ2uwTL3gYBnWqo76ejdazTYJiKtubd37lI qAthnscpNSK2Bq4u02+CEo6yK8Ui3LsY1euE6Zu1EfR0QaICZuqn27eAf Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10286"; a="236415687" X-IronPort-AV: E=Sophos;i="5.90,185,1643702400"; d="scan'208";a="236415687" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Mar 2022 19:10:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,185,1643702400"; d="scan'208";a="644485230" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga002.fm.intel.com with ESMTP; 15 Mar 2022 19:10:05 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id 7105F8E2; Wed, 16 Mar 2022 04:10:10 +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, thomas.lendacky@amd.com, brijesh.singh@amd.com, x86@kernel.org, linux-kernel@vger.kernel.org, "Kirill A . Shutemov" , Dave Hansen Subject: [PATCHv6 18/30] x86/tdx: Port I/O: add early boot support Date: Wed, 16 Mar 2022 05:08:44 +0300 Message-Id: <20220316020856.24435-19-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220316020856.24435-1-kirill.shutemov@linux.intel.com> References: <20220316020856.24435-1-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). At runtime I/O-related #VE exceptions (along with other types) handled by virt_exception_kernel(). Signed-off-by: Andi Kleen Reviewed-by: Dan Williams Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Kirill A. Shutemov Reviewed-by: Thomas Gleixner Reviewed-by: Dave Hansen --- arch/x86/coco/tdx/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/tdx.c b/arch/x86/coco/tdx/tdx.c index 3caa5f551d90..9c331e291bc6 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -411,6 +411,22 @@ static bool handle_io(struct pt_regs *regs, u32 exit_qual) return handle_out(regs, size, port); } +/* + * 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 1093a5e5f446..c70d9bc74b67 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -64,11 +64,15 @@ 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