From patchwork Mon Feb 28 02:12:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Kai" X-Patchwork-Id: 12762290 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 BF379C4332F for ; Mon, 28 Feb 2022 02:14:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232404AbiB1COg (ORCPT ); Sun, 27 Feb 2022 21:14:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232140AbiB1COe (ORCPT ); Sun, 27 Feb 2022 21:14:34 -0500 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B19151314; Sun, 27 Feb 2022 18:13:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646014435; x=1677550435; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=BnYSZkDEfNq6qs3O72hE3RitoTLCTuZUmKqrNKDUKzg=; b=mMCRaForP8SN4WrfVmnhPnwjDDrsUBEGZg4sr9lMU0o7TFMnlDls7Scv mHD6YuPPc89TPTpUddSSVHXdJxlPe0Sqtn/tj+8++FWWMksbXm8TVCtzA IMpn6R19AyVuzfA1W4kMXDVn3LUbKi33R0RN4KACIfx8K1EZIuckGud3U 5eaVPy9xTYFhQSwaydN/WE2K6hs7wT2dc838CVHant50sZxzE5cQFiW7t duJFViyNbjL3QdnUp0LfHegihmS2GSevYyvVgteihIo+vC5SHgTOvsrr8 zjStib/IJnd2w5AEKGZCAUmULrLNB24XnZ1fXLtYGWYgRJI159LC/3tUA Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10271"; a="240191880" X-IronPort-AV: E=Sophos;i="5.90,142,1643702400"; d="scan'208";a="240191880" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Feb 2022 18:13:55 -0800 X-IronPort-AV: E=Sophos;i="5.90,142,1643702400"; d="scan'208";a="777936834" Received: from jdpanhor-mobl2.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.254.49.36]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Feb 2022 18:13:51 -0800 From: Kai Huang To: x86@kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@intel.com, luto@kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com, seanjc@google.com, hpa@zytor.com, peterz@infradead.org, kirill.shutemov@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, tony.luck@intel.com, ak@linux.intel.com, dan.j.williams@intel.com, chang.seok.bae@intel.com, keescook@chromium.org, hengqi.arch@bytedance.com, laijs@linux.alibaba.com, metze@samba.org, linux-kernel@vger.kernel.org, kai.huang@intel.com Subject: [RFC PATCH 03/21] x86/virt/tdx: Implement the SEAMCALL base function Date: Mon, 28 Feb 2022 15:12:51 +1300 Message-Id: <67e0161abb0d0363b810d8539ac8aba139ca7403.1646007267.git.kai.huang@intel.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Secure Arbitration Mode (SEAM) is an extension of VMX architecture. It defines a new VMX root operation (SEAM VMX root) and a new VMX non-root operation (SEAM VMX non-root) which isolate from legacy VMX root and VMX non-root mode. A CPU-attested software module (called 'TDX module') runs in SEAM VMX root to manage the protected VMs running in SEAM VMX non-root. SEAM VMX root is also used to host another CPU-attested software module (called 'P-SEAMLDR') to load and update the TDX module. Host kernel transits to either P-SEAMLDR or TDX module via the new SEAMCALL instruction. SEAMCALLs are host-side interface functions defined by P-SEAMLDR and TDX module around the new SEAMCALL instruction. They are similar to a hypercall, except they are made by host kernel to the SEAM software. SEAMCALLs use an ABI different from the x86-64 system-v ABI. Instead, it shares the same ABI with the TDCALL. %rax is used to carry both the SEAMCALL leaf function number (input) and the completion status code (output). Additional GPRs (%rcx, %rdx, %r8->%r11) may be further used as both input and output operands in individual leaf SEAMCALLs. Implement a C function __seamcall() to do SEAMCALL using the assembly macro used by __tdx_module_call() (the implementation of TDCALL). The only exception not covered here is TDENTER leaf function which takes all GPRs and XMM0-XMM15 as both input and output. The caller of TDENTER should implement its own logic to call TDENTER directly instead of using this function. SEAMCALL instruction is essentially a VMExit from VMX root to SEAM VMX root. It fails with VMfailInvalid when the SEAM software is not loaded. The C function __seamcall() returns TDX_SEAMCALL_VMFAILINVALID, which doesn't conflict with any actual error code of SEAMCALLs, to uniquely represent this case. Signed-off-by: Kai Huang --- arch/x86/virt/vmx/Makefile | 2 +- arch/x86/virt/vmx/seamcall.S | 53 ++++++++++++++++++++++++++++++++++++ arch/x86/virt/vmx/tdx.h | 11 ++++++++ 3 files changed, 65 insertions(+), 1 deletion(-) create mode 100644 arch/x86/virt/vmx/seamcall.S create mode 100644 arch/x86/virt/vmx/tdx.h diff --git a/arch/x86/virt/vmx/Makefile b/arch/x86/virt/vmx/Makefile index 1bd688684716..fd577619620e 100644 --- a/arch/x86/virt/vmx/Makefile +++ b/arch/x86/virt/vmx/Makefile @@ -1,2 +1,2 @@ # SPDX-License-Identifier: GPL-2.0-only -obj-$(CONFIG_INTEL_TDX_HOST) += tdx.o +obj-$(CONFIG_INTEL_TDX_HOST) += tdx.o seamcall.o diff --git a/arch/x86/virt/vmx/seamcall.S b/arch/x86/virt/vmx/seamcall.S new file mode 100644 index 000000000000..65edec23b5f4 --- /dev/null +++ b/arch/x86/virt/vmx/seamcall.S @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include +#include + +#include "../tdxcall.S" + +/* + * __seamcall() - Host-side interface functions to SEAM software + * (P-SEAMLDR or TDX module) + * + * Transform function call register arguments into the SEAMCALL register + * ABI. Return TDX_SEAMCALL_VMFAILINVALID (when SEAM software is not + * loaded or SEAMCALLs are made into P-SEAMLDR concurrently), or the + * completion status of the SEAMCALL. Additional output operands are + * saved in @out (if it is provided by the user). + * + *------------------------------------------------------------------------- + * SEAMCALL ABI: + *------------------------------------------------------------------------- + * Input Registers: + * + * RAX - SEAMCALL Leaf number. + * RCX,RDX,R8-R9 - SEAMCALL Leaf specific input registers. + * + * Output Registers: + * + * RAX - SEAMCALL completion status code. + * RCX,RDX,R8-R11 - SEAMCALL Leaf specific output registers. + * + *------------------------------------------------------------------------- + * + * __seamcall() function ABI: + * + * @fn (RDI) - SEAMCALL Leaf number, moved to RAX + * @rcx (RSI) - Input parameter 1, moved to RCX + * @rdx (RDX) - Input parameter 2, moved to RDX + * @r8 (RCX) - Input parameter 3, moved to R8 + * @r9 (R8) - Input parameter 4, moved to R9 + * + * @out (R9) - struct tdx_module_output pointer + * stored temporarily in R12 (not + * shared with the TDX module). It + * can be NULL. + * + * Return (via RAX) the completion status of the SEAMCALL, or + * TDX_SEAMCALL_VMFAILINVALID. + */ +SYM_FUNC_START(__seamcall) + FRAME_BEGIN + TDX_MODULE_CALL host=1 + FRAME_END + ret +SYM_FUNC_END(__seamcall) diff --git a/arch/x86/virt/vmx/tdx.h b/arch/x86/virt/vmx/tdx.h new file mode 100644 index 000000000000..9d5b6f554c20 --- /dev/null +++ b/arch/x86/virt/vmx/tdx.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _X86_VIRT_TDX_H +#define _X86_VIRT_TDX_H + +#include + +struct tdx_module_output; +u64 __seamcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, + struct tdx_module_output *out); + +#endif