From nobody Tue Dec 16 03:20:12 2025 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 E488AC41513 for ; Tue, 15 Aug 2023 11:03:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236594AbjHOLCy (ORCPT ); Tue, 15 Aug 2023 07:02:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236159AbjHOLCX (ORCPT ); Tue, 15 Aug 2023 07:02:23 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A466B3 for ; Tue, 15 Aug 2023 04:02:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692097342; x=1723633342; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=cGlGp69+Yi04l3Ge9e+rlhaP5w8TZwyOOJNeTUrTOrI=; b=BJl+0haTHFwPnMpjTqKEy8PG5QGg0ajMTiHrwf95kT5o0jAiZSO/0qNd nNyrro2t4cgbGGRZleheOorh0PAqzNojXdytW825WbFr6h0q4L3nSe1CA IqKfOcW8Jh7PxiVJho8TymG+Yc7Zg0kyMeuvqjAOleZ3xumebxceEYitS ros/7uqWCGFMIyqlpHSGVkZTcBlzhqL+Sj2o2DdT1wlmr0dhNmamsqzpO GahIgyIu6G9QWwaE9dAcVvZmIWdQVeAZXssCphujWDghr4mQR0Zbbb8lB FA89Z32EnG/c+GzFWiMSAzoP+MxTqNNFsl14she69egIyHnZVrtNa4j1/ w==; X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148242" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148242" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:22 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236098" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236098" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:18 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 01/12] x86/tdx: Zero out the missing RSI in TDX_HYPERCALL macro Date: Tue, 15 Aug 2023 23:01:55 +1200 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In the TDX_HYPERCALL asm, after the TDCALL instruction returns from the untrusted VMM, the registers that the TDX guest shares to the VMM need to be cleared to avoid speculative execution of VMM-provided values. RSI is specified in the bitmap of those registers, but it is missing when zeroing out those registers in the current TDX_HYPERCALL. It was there when it was originally added in commit 752d13305c78 ("x86/tdx: Expand __tdx_hypercall() to handle more arguments"), but was later removed in commit 1e70c680375a ("x86/tdx: Do not corrupt frame-pointer in __tdx_hypercall()"), which was correct because %rsi is later restored in the "pop %rsi". However a later commit 7a3a401874be ("x86/tdx: Drop flags from __tdx_hypercall()") removed that "pop %rsi" but forgot to add the "xor %rsi, %rsi" back. Fix by adding it back. Fixes: 7a3a401874be ("x86/tdx: Drop flags from __tdx_hypercall()") Signed-off-by: Kai Huang Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) --- arch/x86/coco/tdx/tdcall.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index b193c0a1d8db..2eca5f43734f 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -195,6 +195,7 @@ SYM_FUNC_END(__tdx_module_call) xor %r10d, %r10d xor %r11d, %r11d xor %rdi, %rdi + xor %rsi, %rsi xor %rdx, %rdx =20 /* Restore callee-saved GPRs as mandated by the x86_64 ABI */ --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 F3752C001E0 for ; Tue, 15 Aug 2023 11:03:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236600AbjHOLC4 (ORCPT ); Tue, 15 Aug 2023 07:02:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35514 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236554AbjHOLC0 (ORCPT ); Tue, 15 Aug 2023 07:02:26 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F855B3 for ; Tue, 15 Aug 2023 04:02:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692097346; x=1723633346; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=FF9AK4aYzMRyyloxJNk5SDdphe6M17kEjEyQeszEHqE=; b=fi+Q7++oDGxpMd2f1GUa6NyEFevxtCezrzJDd3G/bdcD1MJdHLkkbFh+ hNi2MIklOgoVxf5ih9CJ5uX/Jg/35A0KmLVXXvpdXGInadPBD37dhvZRH TI9m6hyY/whaAfId8sNu7X3sjo/qv0HRmdXEdcA/dqNzhhPDVysRkt7gq i7HNQDGLdyYagHflI3kmKF79j3jc3uLNreZFDGZZ23VZiWOLvt/ZqNhpd 9cSu5rkfGT43liL+xDLF363dfs+sg41cHC3+gY9J3Gll3csXLaJeR9k0e 6v0b4axGR1pavPIHdPGg6qBA5UT2sZYlzevL1BC9vDt38hLkKcL0GknAQ Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148260" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148260" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236111" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236111" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:22 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 02/12] x86/tdx: Skip saving output regs when SEAMCALL fails with VMFailInvalid Date: Tue, 15 Aug 2023 23:01:56 +1200 Message-ID: <704088f5b4d72c7e24084f7f15bd1ac5005b7213.1692096753.git.kai.huang@intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If SEAMCALL fails with VMFailInvalid, the SEAM software (e.g., the TDX module) won't have chance to set any output register. Skip saving the output registers to the structure in this case. Also, as '.Lno_output_struct' is the very last symbol before RET, rename it to '.Lout' to make it short. Opportunistically make the asm directives unindented. Cc: Kirill A. Shutemov Cc: Dave Hansen Cc: Peter Zijlstra Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kirill A. Shutemov --- v3 -> v4: - No change. v2 -> v3: - No change. v1 -> v2: - A new patch to improve SEAMCALL VMFailInvalid failure, with v1 patch "x86/tdx: Move FRAME_BEGIN/END to TDX_MODULE_CALL asm macro" merged. --- arch/x86/coco/tdx/tdcall.S | 3 --- arch/x86/virt/vmx/tdx/tdxcall.S | 29 ++++++++++++++++++++--------- 2 files changed, 20 insertions(+), 12 deletions(-) diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index 2eca5f43734f..e5d4b7d8ecd4 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -78,10 +78,7 @@ * Return status of TDCALL via RAX. */ SYM_FUNC_START(__tdx_module_call) - FRAME_BEGIN TDX_MODULE_CALL host=3D0 - FRAME_END - RET SYM_FUNC_END(__tdx_module_call) =20 /* diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcal= l.S index 49a54356ae99..6bdf6e137953 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -1,5 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include +#include #include =20 /* @@ -18,6 +19,7 @@ * TDX module. */ .macro TDX_MODULE_CALL host:req + FRAME_BEGIN /* * R12 will be used as temporary storage for struct tdx_module_output * pointer. Since R12-R15 registers are not used by TDCALL/SEAMCALL @@ -44,7 +46,7 @@ mov %rsi, %rcx /* Leave input param 2 in RDX */ =20 - .if \host +.if \host seamcall /* * SEAMCALL instruction is essentially a VMExit from VMX root @@ -57,13 +59,10 @@ * This value will never be used as actual SEAMCALL error code as * it is from the Reserved status code class. */ - jnc .Lno_vmfailinvalid - mov $TDX_SEAMCALL_VMFAILINVALID, %rax -.Lno_vmfailinvalid: - - .else + jc .Lseamcall_vmfailinvalid +.else tdcall - .endif +.endif =20 /* * Fetch output pointer from stack to R12 (It is used @@ -80,7 +79,7 @@ * Other registers may contain details of the failure. */ test %r12, %r12 - jz .Lno_output_struct + jz .Lout =20 /* Copy result registers to output struct: */ movq %rcx, TDX_MODULE_rcx(%r12) @@ -90,7 +89,19 @@ movq %r10, TDX_MODULE_r10(%r12) movq %r11, TDX_MODULE_r11(%r12) =20 -.Lno_output_struct: +.Lout: /* Restore the state of R12 register */ pop %r12 + + FRAME_END + RET + +.if \host +.Lseamcall_vmfailinvalid: + mov $TDX_SEAMCALL_VMFAILINVALID, %rax + /* pop the unused output pointer back to %r9 */ + pop %r9 + jmp .Lout +.endif /* \host */ + .endm --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 1DE45C04E69 for ; Tue, 15 Aug 2023 11:03:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236606AbjHOLC6 (ORCPT ); Tue, 15 Aug 2023 07:02:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236558AbjHOLCa (ORCPT ); Tue, 15 Aug 2023 07:02:30 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C182B3 for ; Tue, 15 Aug 2023 04:02:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692097349; x=1723633349; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=IZ+alnXDfOwrRUZWMFGFpUzYn1twgi8bthwccjxvN8A=; b=EcVxtNfA5toyRO16SYnpF2iNLsduwOQ4s54vNyxjJIvfY707mHg0K8fS Nz4252JW+CQTBegIKGead/PTlWn4uBYtliu92tvHOTg9AvhA1WqCunUYU LKXhJ2u24LYOlNZfvI89pVgJgWGY6SR590WlD6dP4I9+gjCiSKFN9JiwV bzT+KGkCvw0oRI02/U5ZacJrMlCgPxHQyAtNOfNhoi70qosQB7Bw0Zz3Z PMqhJQlsFcW0GW/INawcoGSgPWs8+lKluNFuxGxt0bgPC9ch7O9St0dFY ELKEHgZZ9RIlYTzXEq9JNHCt0wXQOeMaCit2TrB87wS3zMnCKW6TIAO0Z A==; X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148279" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148279" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:29 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236122" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236122" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:25 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 03/12] x86/tdx: Make macros of TDCALLs consistent with the spec Date: Tue, 15 Aug 2023 23:01:57 +1200 Message-ID: <516dccd0bd8fb9a0b6af30d25bb2d971aa03d598.1692096753.git.kai.huang@intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The TDX spec names all TDCALLs with prefix "TDG". Currently, the kernel doesn't follow such convention for the macros of those TDCALLs but uses prefix "TDX_" for all of them. Although it's arguable whether the TDX spec names those TDCALLs properly, it's better for the kernel to follow the spec when naming those macros. Change all macros of TDCALLs to make them consistent with the spec. As a bonus, they get distinguished easily from the host-side SEAMCALLs, which all have prefix "TDH". No functional change intended. Signed-off-by: Kai Huang Reviewed-by: Kirill A. Shutemov Reviewed-by: Kuppuswamy Sathyanarayanan Acked-by: Peter Zijlstra (Intel) --- arch/x86/coco/tdx/tdx-shared.c | 4 ++-- arch/x86/coco/tdx/tdx.c | 8 ++++---- arch/x86/include/asm/shared/tdx.h | 10 +++++----- 3 files changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index ef20ddc37b58..f10cd3e4a04e 100644 --- a/arch/x86/coco/tdx/tdx-shared.c +++ b/arch/x86/coco/tdx/tdx-shared.c @@ -35,7 +35,7 @@ static unsigned long try_accept_one(phys_addr_t start, un= signed long len, } =20 tdcall_rcx =3D start | page_size; - if (__tdx_module_call(TDX_ACCEPT_PAGE, tdcall_rcx, 0, 0, 0, NULL)) + if (__tdx_module_call(TDG_MEM_PAGE_ACCEPT, tdcall_rcx, 0, 0, 0, NULL)) return 0; =20 return accept_size; @@ -45,7 +45,7 @@ bool tdx_accept_memory(phys_addr_t start, phys_addr_t end) { /* * For shared->private conversion, accept the page using - * TDX_ACCEPT_PAGE TDX module call. + * TDG_MEM_PAGE_ACCEPT TDX module call. */ while (start < end) { unsigned long len =3D end - start; diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 1d6b863c42b0..05785df66b1c 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -91,7 +91,7 @@ int tdx_mcall_get_report0(u8 *reportdata, u8 *tdreport) { u64 ret; =20 - ret =3D __tdx_module_call(TDX_GET_REPORT, virt_to_phys(tdreport), + ret =3D __tdx_module_call(TDG_MR_REPORT, virt_to_phys(tdreport), virt_to_phys(reportdata), TDREPORT_SUBTYPE_0, 0, NULL); if (ret) { @@ -152,7 +152,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL * [TDG.VP.INFO]. */ - tdx_module_call(TDX_GET_INFO, 0, 0, 0, 0, &out); + tdx_module_call(TDG_VP_INFO, 0, 0, 0, 0, &out); =20 /* * The highest bit of a guest physical address is the "sharing" bit. @@ -594,7 +594,7 @@ void tdx_get_ve_info(struct ve_info *ve) * Note, the TDX module treats virtual NMIs as inhibited if the #VE * valid flag is set. It means that NMI=3D>#VE will not result in a #DF. */ - tdx_module_call(TDX_GET_VEINFO, 0, 0, 0, 0, &out); + tdx_module_call(TDG_VP_VEINFO_GET, 0, 0, 0, 0, &out); =20 /* Transfer the output parameters */ ve->exit_reason =3D out.rcx; @@ -774,7 +774,7 @@ void __init tdx_early_init(void) cc_set_mask(cc_mask); =20 /* Kernel does not use NOTIFY_ENABLES and does not need random #VEs */ - tdx_module_call(TDX_WR, 0, TDCS_NOTIFY_ENABLES, 0, -1ULL, NULL); + tdx_module_call(TDG_VM_WR, 0, TDCS_NOTIFY_ENABLES, 0, -1ULL, NULL); =20 /* * All bits above GPA width are reserved and kernel treats shared bit diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/share= d/tdx.h index 7513b3bb69b7..78f109446da6 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -11,11 +11,11 @@ #define TDX_IDENT "IntelTDX " =20 /* TDX module Call Leaf IDs */ -#define TDX_GET_INFO 1 -#define TDX_GET_VEINFO 3 -#define TDX_GET_REPORT 4 -#define TDX_ACCEPT_PAGE 6 -#define TDX_WR 8 +#define TDG_VP_INFO 1 +#define TDG_VP_VEINFO_GET 3 +#define TDG_MR_REPORT 4 +#define TDG_MEM_PAGE_ACCEPT 6 +#define TDG_VM_WR 8 =20 /* TDCS fields. To be used by TDG.VM.WR and TDG.VM.RD module calls */ #define TDCS_NOTIFY_ENABLES 0x9100000000000010 --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 2E09FC04A94 for ; Tue, 15 Aug 2023 11:03:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236614AbjHOLDB (ORCPT ); Tue, 15 Aug 2023 07:03:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236560AbjHOLCe (ORCPT ); Tue, 15 Aug 2023 07:02:34 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 068F7B3 for ; Tue, 15 Aug 2023 04:02:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692097353; x=1723633353; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=aU41zTMOi0OcoqQGhhkoosnRYdnzUgqsgizCGwT8EyQ=; b=CPPEqqAEdmedWWXk/pSGs3f+dJmuNr2PCqd4DkldcfSIjgrps/ZrZQOh 9bfxGr1QhEmmuhwXtCxvdtRmcBcsaNlo2mjEYkKeA2/lK0FLse4NxOgqC 5TgZrwklReXJh0oToMDQ81G9OgYhsxBFUkAxXhCh42A+nwTUrfFhiLg+H sI5SIos+3Hs1V5W6FuWgmkfhdERfXgLhVvUaTSBGpPoLHDXq8/eBSl/8R +QY6hE2OYFLjneHOhGuAYYU4Tlzfmok54wzlb6x2hKvUaTXLOlZEV5mzo dW7Wunki19KHOyj+UmKaATXIGKEiYkKxo3smcoq8wx2585B12nVQgTuD6 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148293" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148293" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236132" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236132" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:29 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 04/12] x86/tdx: Rename __tdx_module_call() to __tdcall() Date: Tue, 15 Aug 2023 23:01:58 +1200 Message-ID: <785d20d99fbcd0db8262c94da6423375422d8c75.1692096753.git.kai.huang@intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" __tdx_module_call() is only used by the TDX guest to issue TDCALL to the TDX module. Rename it to __tdcall() to match its behaviour, e.g., it cannot be used to make host-side SEAMCALL. Also rename tdx_module_call() which is a wrapper of __tdx_module_call() to tdcall(). No functional change intended. Signed-off-by: Kai Huang Reviewed-by: Kirill A. Shutemov Reviewed-by: Kuppuswamy Sathyanarayanan Acked-by: Peter Zijlstra (Intel) --- arch/x86/coco/tdx/tdcall.S | 10 +++++----- arch/x86/coco/tdx/tdx-shared.c | 2 +- arch/x86/coco/tdx/tdx.c | 18 +++++++++--------- arch/x86/include/asm/shared/tdx.h | 4 ++-- 4 files changed, 17 insertions(+), 17 deletions(-) diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index e5d4b7d8ecd4..6aebac08f2bf 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -40,8 +40,8 @@ .section .noinstr.text, "ax" =20 /* - * __tdx_module_call() - Used by TDX guests to request services from - * the TDX module (does not include VMM services) using TDCALL instruction. + * __tdcall() - Used by TDX guests to request services from the TDX + * module (does not include VMM services) using TDCALL instruction. * * Transforms function call register arguments into the TDCALL register AB= I. * After TDCALL operation, TDX module output is saved in @out (if it is @@ -62,7 +62,7 @@ * *------------------------------------------------------------------------- * - * __tdx_module_call() function ABI: + * __tdcall() function ABI: * * @fn (RDI) - TDCALL Leaf ID, moved to RAX * @rcx (RSI) - Input parameter 1, moved to RCX @@ -77,9 +77,9 @@ * * Return status of TDCALL via RAX. */ -SYM_FUNC_START(__tdx_module_call) +SYM_FUNC_START(__tdcall) TDX_MODULE_CALL host=3D0 -SYM_FUNC_END(__tdx_module_call) +SYM_FUNC_END(__tdcall) =20 /* * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDC= ALL diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index f10cd3e4a04e..90631abdac34 100644 --- a/arch/x86/coco/tdx/tdx-shared.c +++ b/arch/x86/coco/tdx/tdx-shared.c @@ -35,7 +35,7 @@ static unsigned long try_accept_one(phys_addr_t start, un= signed long len, } =20 tdcall_rcx =3D start | page_size; - if (__tdx_module_call(TDG_MEM_PAGE_ACCEPT, tdcall_rcx, 0, 0, 0, NULL)) + if (__tdcall(TDG_MEM_PAGE_ACCEPT, tdcall_rcx, 0, 0, 0, NULL)) return 0; =20 return accept_size; diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 05785df66b1c..8c13944925e3 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -66,10 +66,10 @@ EXPORT_SYMBOL_GPL(tdx_kvm_hypercall); * should only be used for calls that have no legitimate reason to fail * or where the kernel can not survive the call failing. */ -static inline void tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r= 9, - struct tdx_module_output *out) +static inline void tdcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, + struct tdx_module_output *out) { - if (__tdx_module_call(fn, rcx, rdx, r8, r9, out)) + if (__tdcall(fn, rcx, rdx, r8, r9, out)) panic("TDCALL %lld failed (Buggy TDX module!)\n", fn); } =20 @@ -91,9 +91,9 @@ int tdx_mcall_get_report0(u8 *reportdata, u8 *tdreport) { u64 ret; =20 - ret =3D __tdx_module_call(TDG_MR_REPORT, virt_to_phys(tdreport), - virt_to_phys(reportdata), TDREPORT_SUBTYPE_0, - 0, NULL); + ret =3D __tdcall(TDG_MR_REPORT, virt_to_phys(tdreport), + virt_to_phys(reportdata), TDREPORT_SUBTYPE_0, + 0, NULL); if (ret) { if (TDCALL_RETURN_CODE(ret) =3D=3D TDCALL_INVALID_OPERAND) return -EINVAL; @@ -152,7 +152,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL * [TDG.VP.INFO]. */ - tdx_module_call(TDG_VP_INFO, 0, 0, 0, 0, &out); + tdcall(TDG_VP_INFO, 0, 0, 0, 0, &out); =20 /* * The highest bit of a guest physical address is the "sharing" bit. @@ -594,7 +594,7 @@ void tdx_get_ve_info(struct ve_info *ve) * Note, the TDX module treats virtual NMIs as inhibited if the #VE * valid flag is set. It means that NMI=3D>#VE will not result in a #DF. */ - tdx_module_call(TDG_VP_VEINFO_GET, 0, 0, 0, 0, &out); + tdcall(TDG_VP_VEINFO_GET, 0, 0, 0, 0, &out); =20 /* Transfer the output parameters */ ve->exit_reason =3D out.rcx; @@ -774,7 +774,7 @@ void __init tdx_early_init(void) cc_set_mask(cc_mask); =20 /* Kernel does not use NOTIFY_ENABLES and does not need random #VEs */ - tdx_module_call(TDG_VM_WR, 0, TDCS_NOTIFY_ENABLES, 0, -1ULL, NULL); + tdcall(TDG_VM_WR, 0, TDCS_NOTIFY_ENABLES, 0, -1ULL, NULL); =20 /* * All bits above GPA width are reserved and kernel treats shared bit diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/share= d/tdx.h index 78f109446da6..9e3699b751ef 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -88,8 +88,8 @@ struct tdx_module_output { }; =20 /* Used to communicate with the TDX module */ -u64 __tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, - struct tdx_module_output *out); +u64 __tdcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, + struct tdx_module_output *out); =20 bool tdx_accept_memory(phys_addr_t start, phys_addr_t end); =20 --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 3E1D3C04FE0 for ; Tue, 15 Aug 2023 11:03:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236619AbjHOLDF (ORCPT ); Tue, 15 Aug 2023 07:03:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50024 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236564AbjHOLCi (ORCPT ); Tue, 15 Aug 2023 07:02:38 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 896B8B3 for ; Tue, 15 Aug 2023 04:02:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692097356; x=1723633356; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=mgdHKMdY17RRP3Xz/RQdfc5exF7KlHM8HjyxP9C80sY=; b=X0bpE2RqH1coWoHmPue3VauLVQsM4f9zKsvz6cRRHUlVScxbqRO4PZUE g3pCQEH8MGX+FCBm2bgpcGR7Yget8b7+PIEV9WVWaxBKrDSsJGNLN3PKE LuKGuEB7LvH71w0N3LGLrwm5q8R20zs9/CBVtzPo8+muL/SCkhyjejS03 wkd/8KU7MNZ1Ci5+Ow6CRuIH8gb1v7DxDlnJO157wdkR2dpYPfPbROPeL L6sWSIZvzH1lgmLgHiSd2cHgR3Ue2CzEL4kMMDLv5Lk71DabrRUUXFPSX vYC0tB1RUxkosPhvtojzVU+cvaeNW6+0pvI9DGo1IMCNVFEsu9Zwc/Wbi Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148307" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148307" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236143" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236143" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:32 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 05/12] x86/tdx: Pass TDCALL/SEAMCALL input/output registers via a structure Date: Tue, 15 Aug 2023 23:01:59 +1200 Message-ID: <483616c1762d85eb3a3c3035a7de061cfacf2f14.1692096753.git.kai.huang@intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Currently, the TDX_MODULE_CALL asm macro, which handles both TDCALL and SEAMCALL, takes one parameter for each input register and an optional 'struct tdx_module_output' (a collection of output registers) as output. This is different from the TDX_HYPERCALL macro which uses a single 'struct tdx_hypercall_args' to carry all input/output registers. The newer TDX versions introduce more TDCALLs/SEAMCALLs which use more input/output registers. Also, the TDH.VP.ENTER (which isn't covered by the current TDX_MODULE_CALL macro) basically can use all registers that the TDX_HYPERCALL does. The current TDX_MODULE_CALL macro isn't extendible to cover those cases. Similar to the TDX_HYPERCALL macro, simplify the TDX_MODULE_CALL macro to use a single structure 'struct tdx_module_args' to carry all the input/output registers. Currently, R10/R11 are only used as output register but not as input by any TDCALL/SEAMCALL. Change to also use R10/R11 as input register to make input/output registers symmetric. Currently, the TDX_MODULE_CALL macro depends on the caller to pass a non-NULL 'struct tdx_module_output' to get additional output registers. Similar to the TDX_HYPERCALL macro, change the TDX_MODULE_CALL macro to take a new 'ret' macro argument to indicate whether to save the output registers to the 'struct tdx_module_args'. Also introduce a new __tdcall_ret() for that purpose, similar to the __tdx_hypercall_ret(). Note the tdcall(), which is a wrapper of __tdcall(), is called by three callers: tdx_parse_tdinfo(), tdx_get_ve_info() and tdx_early_init(). The former two need the additional output but the last one doesn't. For simplicity, make tdcall() always call __tdcall_ret() to avoid another "_ret()" wrapper. The last caller tdx_early_init() isn't performance critical anyway. Cc: Kirill A. Shutemov Cc: Dave Hansen Cc: Peter Zijlstra Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kirill A. Shutemov --- v3 -> v4: - Also use R10/R11 as input registers. - Kirill v2 -> v3: - No change. v1 -> v2: - Code change due to patch 02. - Minor improvement in comments and changelog. --- arch/x86/coco/tdx/tdcall.S | 47 ++++++--------- arch/x86/coco/tdx/tdx-shared.c | 6 +- arch/x86/coco/tdx/tdx.c | 44 ++++++++------ arch/x86/include/asm/shared/tdx.h | 8 +-- arch/x86/kernel/asm-offsets.c | 12 ++-- arch/x86/virt/vmx/tdx/tdxcall.S | 97 +++++++++++++------------------ 6 files changed, 96 insertions(+), 118 deletions(-) diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index 6aebac08f2bf..56b9cd32895e 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -43,37 +43,10 @@ * __tdcall() - Used by TDX guests to request services from the TDX * module (does not include VMM services) using TDCALL instruction. * - * Transforms function call register arguments into the TDCALL register AB= I. - * After TDCALL operation, TDX module output is saved in @out (if it is - * provided by the user). - * - *------------------------------------------------------------------------- - * TDCALL ABI: - *------------------------------------------------------------------------- - * Input Registers: - * - * RAX - TDCALL Leaf number. - * RCX,RDX,R8-R9 - TDCALL Leaf specific input registers. - * - * Output Registers: - * - * RAX - TDCALL instruction error code. - * RCX,RDX,R8-R11 - TDCALL Leaf specific output registers. - * - *------------------------------------------------------------------------- - * * __tdcall() function ABI: * - * @fn (RDI) - TDCALL Leaf ID, 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. + * @fn (RDI) - TDCALL Leaf ID, moved to RAX + * @args (RSI) - struct tdx_module_args for input * * Return status of TDCALL via RAX. */ @@ -81,6 +54,22 @@ SYM_FUNC_START(__tdcall) TDX_MODULE_CALL host=3D0 SYM_FUNC_END(__tdcall) =20 +/* + * __tdcall_ret() - Used by TDX guests to request services from the TDX + * module (does not include VMM services) using TDCALL instruction, with + * saving output registers to the 'struct tdx_module_args' used as input. + * + * __tdcall_ret() function ABI: + * + * @fn (RDI) - TDCALL Leaf ID, moved to RAX + * @args (RSI) - struct tdx_module_args for input and output + * + * Return status of TDCALL via RAX. + */ +SYM_FUNC_START(__tdcall_ret) + TDX_MODULE_CALL host=3D0 ret=3D1 +SYM_FUNC_END(__tdcall_ret) + /* * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDC= ALL * instruction diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index 90631abdac34..a7396d0ddef9 100644 --- a/arch/x86/coco/tdx/tdx-shared.c +++ b/arch/x86/coco/tdx/tdx-shared.c @@ -5,7 +5,7 @@ static unsigned long try_accept_one(phys_addr_t start, unsi= gned long len, enum pg_level pg_level) { unsigned long accept_size =3D page_level_size(pg_level); - u64 tdcall_rcx; + struct tdx_module_args args =3D {}; u8 page_size; =20 if (!IS_ALIGNED(start, accept_size)) @@ -34,8 +34,8 @@ static unsigned long try_accept_one(phys_addr_t start, un= signed long len, return 0; } =20 - tdcall_rcx =3D start | page_size; - if (__tdcall(TDG_MEM_PAGE_ACCEPT, tdcall_rcx, 0, 0, 0, NULL)) + args.rcx =3D start | page_size; + if (__tdcall(TDG_MEM_PAGE_ACCEPT, &args)) return 0; =20 return accept_size; diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 8c13944925e3..2e19cc62e59e 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -66,10 +66,9 @@ EXPORT_SYMBOL_GPL(tdx_kvm_hypercall); * should only be used for calls that have no legitimate reason to fail * or where the kernel can not survive the call failing. */ -static inline void tdcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, - struct tdx_module_output *out) +static inline void tdcall(u64 fn, struct tdx_module_args *args) { - if (__tdcall(fn, rcx, rdx, r8, r9, out)) + if (__tdcall_ret(fn, args)) panic("TDCALL %lld failed (Buggy TDX module!)\n", fn); } =20 @@ -89,11 +88,14 @@ static inline void tdcall(u64 fn, u64 rcx, u64 rdx, u64= r8, u64 r9, */ int tdx_mcall_get_report0(u8 *reportdata, u8 *tdreport) { + struct tdx_module_args args =3D { + .rcx =3D virt_to_phys(tdreport), + .rdx =3D virt_to_phys(reportdata), + .r8 =3D TDREPORT_SUBTYPE_0, + }; u64 ret; =20 - ret =3D __tdcall(TDG_MR_REPORT, virt_to_phys(tdreport), - virt_to_phys(reportdata), TDREPORT_SUBTYPE_0, - 0, NULL); + ret =3D __tdcall(TDG_MR_REPORT, &args); if (ret) { if (TDCALL_RETURN_CODE(ret) =3D=3D TDCALL_INVALID_OPERAND) return -EINVAL; @@ -141,7 +143,7 @@ static void __noreturn tdx_panic(const char *msg) =20 static void tdx_parse_tdinfo(u64 *cc_mask) { - struct tdx_module_output out; + struct tdx_module_args args =3D {}; unsigned int gpa_width; u64 td_attr; =20 @@ -152,7 +154,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL * [TDG.VP.INFO]. */ - tdcall(TDG_VP_INFO, 0, 0, 0, 0, &out); + tdcall(TDG_VP_INFO, &args); =20 /* * The highest bit of a guest physical address is the "sharing" bit. @@ -161,7 +163,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * The GPA width that comes out of this call is critical. TDX guests * can not meaningfully run without it. */ - gpa_width =3D out.rcx & GENMASK(5, 0); + gpa_width =3D args.rcx & GENMASK(5, 0); *cc_mask =3D BIT_ULL(gpa_width - 1); =20 /* @@ -169,7 +171,7 @@ static void tdx_parse_tdinfo(u64 *cc_mask) * memory. Ensure that no #VE will be delivered for accesses to * TD-private memory. Only VMM-shared memory (MMIO) will #VE. */ - td_attr =3D out.rdx; + td_attr =3D args.rdx; if (!(td_attr & ATTR_SEPT_VE_DISABLE)) { const char *msg =3D "TD misconfiguration: SEPT_VE_DISABLE attribute must= be set."; =20 @@ -577,7 +579,7 @@ __init bool tdx_early_handle_ve(struct pt_regs *regs) =20 void tdx_get_ve_info(struct ve_info *ve) { - struct tdx_module_output out; + struct tdx_module_args args =3D {}; =20 /* * Called during #VE handling to retrieve the #VE info from the @@ -594,15 +596,15 @@ void tdx_get_ve_info(struct ve_info *ve) * Note, the TDX module treats virtual NMIs as inhibited if the #VE * valid flag is set. It means that NMI=3D>#VE will not result in a #DF. */ - tdcall(TDG_VP_VEINFO_GET, 0, 0, 0, 0, &out); + tdcall(TDG_VP_VEINFO_GET, &args); =20 /* Transfer the output parameters */ - ve->exit_reason =3D out.rcx; - ve->exit_qual =3D out.rdx; - ve->gla =3D out.r8; - ve->gpa =3D out.r9; - ve->instr_len =3D lower_32_bits(out.r10); - ve->instr_info =3D upper_32_bits(out.r10); + ve->exit_reason =3D args.rcx; + ve->exit_qual =3D args.rdx; + ve->gla =3D args.r8; + ve->gpa =3D args.r9; + ve->instr_len =3D lower_32_bits(args.r10); + ve->instr_info =3D upper_32_bits(args.r10); } =20 /* @@ -759,6 +761,10 @@ static bool tdx_enc_status_change_finish(unsigned long= vaddr, int numpages, =20 void __init tdx_early_init(void) { + struct tdx_module_args args =3D { + .rdx =3D TDCS_NOTIFY_ENABLES, + .r9 =3D -1ULL, + }; u64 cc_mask; u32 eax, sig[3]; =20 @@ -774,7 +780,7 @@ void __init tdx_early_init(void) cc_set_mask(cc_mask); =20 /* Kernel does not use NOTIFY_ENABLES and does not need random #VEs */ - tdcall(TDG_VM_WR, 0, TDCS_NOTIFY_ENABLES, 0, -1ULL, NULL); + tdcall(TDG_VM_WR, &args); =20 /* * All bits above GPA width are reserved and kernel treats shared bit diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/share= d/tdx.h index 9e3699b751ef..3606463ebf6f 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -74,11 +74,11 @@ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r= 13, u64 r14, u64 r15) void __tdx_hypercall_failed(void); =20 /* - * Used in __tdx_module_call() to gather the output registers' values of t= he + * Used in __tdcall*() to gather the input/output registers' values of the * TDCALL instruction when requesting services from the TDX module. This i= s a * software only structure and not part of the TDX module/VMM ABI */ -struct tdx_module_output { +struct tdx_module_args { u64 rcx; u64 rdx; u64 r8; @@ -88,8 +88,8 @@ struct tdx_module_output { }; =20 /* Used to communicate with the TDX module */ -u64 __tdcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, - struct tdx_module_output *out); +u64 __tdcall(u64 fn, struct tdx_module_args *args); +u64 __tdcall_ret(u64 fn, struct tdx_module_args *args); =20 bool tdx_accept_memory(phys_addr_t start, phys_addr_t end); =20 diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index dc3576303f1a..50383bc46dd7 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -68,12 +68,12 @@ static void __used common(void) #endif =20 BLANK(); - OFFSET(TDX_MODULE_rcx, tdx_module_output, rcx); - OFFSET(TDX_MODULE_rdx, tdx_module_output, rdx); - OFFSET(TDX_MODULE_r8, tdx_module_output, r8); - OFFSET(TDX_MODULE_r9, tdx_module_output, r9); - OFFSET(TDX_MODULE_r10, tdx_module_output, r10); - OFFSET(TDX_MODULE_r11, tdx_module_output, r11); + OFFSET(TDX_MODULE_rcx, tdx_module_args, rcx); + OFFSET(TDX_MODULE_rdx, tdx_module_args, rdx); + OFFSET(TDX_MODULE_r8, tdx_module_args, r8); + OFFSET(TDX_MODULE_r9, tdx_module_args, r9); + OFFSET(TDX_MODULE_r10, tdx_module_args, r10); + OFFSET(TDX_MODULE_r11, tdx_module_args, r11); =20 BLANK(); OFFSET(TDX_HYPERCALL_r8, tdx_hypercall_args, r8); diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcal= l.S index 6bdf6e137953..e9e19e7d77f8 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -17,34 +17,35 @@ * TDX module and hypercalls to the VMM. * SEAMCALL - used by TDX hosts to make requests to the * TDX module. + * + *------------------------------------------------------------------------- + * TDCALL/SEAMCALL ABI: + *------------------------------------------------------------------------- + * Input Registers: + * + * RAX - TDCALL/SEAMCALL Leaf number. + * RCX,RDX,R8-R11 - TDCALL/SEAMCALL Leaf specific input registers. + * + * Output Registers: + * + * RAX - TDCALL/SEAMCALL instruction error code. + * RCX,RDX,R8-R11 - TDCALL/SEAMCALL Leaf specific output registers. + * + *------------------------------------------------------------------------- */ -.macro TDX_MODULE_CALL host:req +.macro TDX_MODULE_CALL host:req ret=3D0 FRAME_BEGIN - /* - * R12 will be used as temporary storage for struct tdx_module_output - * pointer. Since R12-R15 registers are not used by TDCALL/SEAMCALL - * services supported by this function, it can be reused. - */ =20 - /* Callee saved, so preserve it */ - push %r12 - - /* - * Push output pointer to stack. - * After the operation, it will be fetched into R12 register. - */ - push %r9 - - /* Mangle function call ABI into TDCALL/SEAMCALL ABI: */ /* Move Leaf ID to RAX */ mov %rdi, %rax - /* Move input 4 to R9 */ - mov %r8, %r9 - /* Move input 3 to R8 */ - mov %rcx, %r8 - /* Move input 1 to RCX */ - mov %rsi, %rcx - /* Leave input param 2 in RDX */ + + /* Move other input regs from 'struct tdx_module_args' */ + movq TDX_MODULE_rcx(%rsi), %rcx + movq TDX_MODULE_rdx(%rsi), %rdx + movq TDX_MODULE_r8(%rsi), %r8 + movq TDX_MODULE_r9(%rsi), %r9 + movq TDX_MODULE_r10(%rsi), %r10 + movq TDX_MODULE_r11(%rsi), %r11 =20 .if \host seamcall @@ -59,49 +60,31 @@ * This value will never be used as actual SEAMCALL error code as * it is from the Reserved status code class. */ - jc .Lseamcall_vmfailinvalid + jc .Lseamcall_vmfailinvalid\@ .else tdcall .endif =20 - /* - * Fetch output pointer from stack to R12 (It is used - * as temporary storage) - */ - pop %r12 - - /* - * Since this macro can be invoked with NULL as an output pointer, - * check if caller provided an output struct before storing output - * registers. - * - * Update output registers, even if the call failed (RAX !=3D 0). - * Other registers may contain details of the failure. - */ - test %r12, %r12 - jz .Lout - - /* Copy result registers to output struct: */ - movq %rcx, TDX_MODULE_rcx(%r12) - movq %rdx, TDX_MODULE_rdx(%r12) - movq %r8, TDX_MODULE_r8(%r12) - movq %r9, TDX_MODULE_r9(%r12) - movq %r10, TDX_MODULE_r10(%r12) - movq %r11, TDX_MODULE_r11(%r12) - -.Lout: - /* Restore the state of R12 register */ - pop %r12 - +.if \ret + /* Copy output registers to the structure */ + movq %rcx, TDX_MODULE_rcx(%rsi) + movq %rdx, TDX_MODULE_rdx(%rsi) + movq %r8, TDX_MODULE_r8(%rsi) + movq %r9, TDX_MODULE_r9(%rsi) + movq %r10, TDX_MODULE_r10(%rsi) + movq %r11, TDX_MODULE_r11(%rsi) +.endif + +.if \host +.Lout\@: +.endif FRAME_END RET =20 .if \host -.Lseamcall_vmfailinvalid: +.Lseamcall_vmfailinvalid\@: mov $TDX_SEAMCALL_VMFAILINVALID, %rax - /* pop the unused output pointer back to %r9 */ - pop %r9 - jmp .Lout + jmp .Lout\@ .endif /* \host */ =20 .endm --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 4EC46C04FDF for ; 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X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148324" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148324" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236155" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236155" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:36 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 06/12] x86/tdx: Extend TDX_MODULE_CALL to support more TDCALL/SEAMCALL leafs Date: Tue, 15 Aug 2023 23:02:00 +1200 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The TDX guest live migration support (TDX 1.5) adds new TDCALL/SEAMCALL leaf functions. Those new TDCALLs/SEAMCALLs take additional registers for input (R10-R13) and output (R12-R13). TDG.SERVTD.RD is an example. Also, the current TDX_MODULE_CALL doesn't aim to handle TDH.VP.ENTER SEAMCALL, which monitors the TDG.VP.VMCALL in input/output registers when it returns in case of VMCALL from TDX guest. With those new TDCALLs/SEAMCALLs and the TDH.VP.ENTER covered, the TDX_MODULE_CALL macro basically needs to handle the same input/output registers as the TDX_HYPERCALL does. And as a result, they also share similar logic in the assembly, thus should be unified to use one common assembly. Extend the TDX_MODULE_CALL asm to support the new TDCALLs/SEAMCALLs and also the TDH.VP.ENTER SEAMCALL. Eventually it will be unified with the TDX_HYPERCALL. The new input/output registers fit with the "callee-saved" registers in the x86 calling convention. Add a new "saved" parameter to support those new TDCALLs/SEAMCALLs and TDH.VP.ENTER and keep the existing TDCALLs/SEAMCALLs minimally impacted. For TDH.VP.ENTER, after it returns the registers shared by the guest contain guest's values. Explicitly clear them to prevent speculative use of guest's values. Note most TDX live migration related SEAMCALLs may also clobber AVX* state ("AVX, AVX2 and AVX512 state: may be reset to the architectural INIT state" -- see TDH.EXPORT.MEM for example). And TDH.VP.ENTER also clobbers XMM0-XMM15 when the corresponding bit is set in RCX. Don't handle them in the TDX_MODULE_CALL macro but let the caller save and restore when needed. This is basically based on Peter's code. Cc: Kirill A. Shutemov Cc: Dave Hansen Cc: Peter Zijlstra Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Reviewed-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) --- v3 -> v4: - Removed unnecessary 'movq %rax, %rsi'. - Kirill - Changed '%rsi' -> 'RSI' in the comments. - Kirill - Added Kirill's Reviewed-by tag v2 -> v3: - No change. v1 -> v2: - xorq %rcx, %rcx -> xorl %eax, %eax to save the REX prefix - Minor improvement in comments and changelog. --- arch/x86/coco/tdx/tdcall.S | 4 + arch/x86/include/asm/shared/tdx.h | 10 +++ arch/x86/kernel/asm-offsets.c | 7 ++ arch/x86/virt/vmx/tdx/tdxcall.S | 123 ++++++++++++++++++++++++++++-- 4 files changed, 138 insertions(+), 6 deletions(-) diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index 56b9cd32895e..faf731d2b66a 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -48,6 +48,8 @@ * @fn (RDI) - TDCALL Leaf ID, moved to RAX * @args (RSI) - struct tdx_module_args for input * + * Only RCX/RDX/R8-R11 are used as input registers. + * * Return status of TDCALL via RAX. */ SYM_FUNC_START(__tdcall) @@ -64,6 +66,8 @@ SYM_FUNC_END(__tdcall) * @fn (RDI) - TDCALL Leaf ID, moved to RAX * @args (RSI) - struct tdx_module_args for input and output * + * Only RCX/RDX/R8-R11 are used as input/output registers. + * * Return status of TDCALL via RAX. */ SYM_FUNC_START(__tdcall_ret) diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/share= d/tdx.h index 3606463ebf6f..4468988adec5 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -79,12 +79,22 @@ void __tdx_hypercall_failed(void); * software only structure and not part of the TDX module/VMM ABI */ struct tdx_module_args { + /* callee-clobbered */ u64 rcx; u64 rdx; u64 r8; u64 r9; + /* extra callee-clobbered */ u64 r10; u64 r11; + /* callee-saved + rdi/rsi */ + u64 r12; + u64 r13; + u64 r14; + u64 r15; + u64 rbx; + u64 rdi; + u64 rsi; }; =20 /* Used to communicate with the TDX module */ diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 50383bc46dd7..1581564a67b7 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -74,6 +74,13 @@ static void __used common(void) OFFSET(TDX_MODULE_r9, tdx_module_args, r9); OFFSET(TDX_MODULE_r10, tdx_module_args, r10); OFFSET(TDX_MODULE_r11, tdx_module_args, r11); + OFFSET(TDX_MODULE_r12, tdx_module_args, r12); + OFFSET(TDX_MODULE_r13, tdx_module_args, r13); + OFFSET(TDX_MODULE_r14, tdx_module_args, r14); + OFFSET(TDX_MODULE_r15, tdx_module_args, r15); + OFFSET(TDX_MODULE_rbx, tdx_module_args, rbx); + OFFSET(TDX_MODULE_rdi, tdx_module_args, rdi); + OFFSET(TDX_MODULE_rsi, tdx_module_args, rsi); =20 BLANK(); OFFSET(TDX_HYPERCALL_r8, tdx_hypercall_args, r8); diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcal= l.S index e9e19e7d77f8..c54ea009b241 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -23,17 +23,25 @@ *------------------------------------------------------------------------- * Input Registers: * - * RAX - TDCALL/SEAMCALL Leaf number. - * RCX,RDX,R8-R11 - TDCALL/SEAMCALL Leaf specific input registers. + * RAX - TDCALL/SEAMCALL Leaf number. + * RCX,RDX,RDI,RSI,RBX,R8-R15 - TDCALL/SEAMCALL Leaf specific input regist= ers. * * Output Registers: * - * RAX - TDCALL/SEAMCALL instruction error code. - * RCX,RDX,R8-R11 - TDCALL/SEAMCALL Leaf specific output registers. + * RAX - TDCALL/SEAMCALL instruction error code. + * RCX,RDX,RDI,RSI,RBX,R8-R15 - TDCALL/SEAMCALL Leaf specific output regis= ters. * *------------------------------------------------------------------------- + * + * So while the common core (RAX,RCX,RDX,R8-R11) fits nicely in the + * callee-clobbered registers and even leaves RDI,RSI free to act as a + * base pointer, some leafs (e.g., VP.ENTER) make a giant mess of things. + * + * For simplicity, assume that anything that needs the callee-saved regs + * also tramples on RDI,RSI. This isn't strictly true, see for example + * TDH.EXPORT.MEM. */ -.macro TDX_MODULE_CALL host:req ret=3D0 +.macro TDX_MODULE_CALL host:req ret=3D0 saved=3D0 FRAME_BEGIN =20 /* Move Leaf ID to RAX */ @@ -47,6 +55,35 @@ movq TDX_MODULE_r10(%rsi), %r10 movq TDX_MODULE_r11(%rsi), %r11 =20 +.if \saved + /* + * Move additional input regs from the structure. For simplicity + * assume that anything needs the callee-saved regs also tramples + * on RDI/RSI (see VP.ENTER). + */ + /* Save those callee-saved GPRs as mandated by the x86_64 ABI */ + pushq %rbx + pushq %r12 + pushq %r13 + pushq %r14 + pushq %r15 + + movq TDX_MODULE_r12(%rsi), %r12 + movq TDX_MODULE_r13(%rsi), %r13 + movq TDX_MODULE_r14(%rsi), %r14 + movq TDX_MODULE_r15(%rsi), %r15 + movq TDX_MODULE_rbx(%rsi), %rbx + +.if \ret + /* Save the structure pointer as RSI is about to be clobbered */ + pushq %rsi +.endif + + movq TDX_MODULE_rdi(%rsi), %rdi + /* RSI needs to be done at last */ + movq TDX_MODULE_rsi(%rsi), %rsi +.endif /* \saved */ + .if \host seamcall /* @@ -66,6 +103,36 @@ .endif =20 .if \ret +.if \saved + /* + * Restore the structure from stack to save the output registers + * + * In case of VP.ENTER returns due to TDVMCALL, all registers are + * valid thus no register can be used as spare to restore the + * structure from the stack (see "TDH.VP.ENTER Output Operands + * Definition on TDCALL(TDG.VP.VMCALL) Following a TD Entry"). + * For this case, need to make one register as spare by saving it + * to the stack and then manually load the structure pointer to + * the spare register. + * + * Note for other TDCALLs/SEAMCALLs there are spare registers + * thus no need for such hack but just use this for all. + */ + pushq %rax /* save the TDCALL/SEAMCALL return code */ + movq 8(%rsp), %rax /* restore the structure pointer */ + movq %rsi, TDX_MODULE_rsi(%rax) /* save RSI */ + popq %rax /* restore the return code */ + popq %rsi /* pop the structure pointer */ + + /* Copy additional output regs to the structure */ + movq %r12, TDX_MODULE_r12(%rsi) + movq %r13, TDX_MODULE_r13(%rsi) + movq %r14, TDX_MODULE_r14(%rsi) + movq %r15, TDX_MODULE_r15(%rsi) + movq %rbx, TDX_MODULE_rbx(%rsi) + movq %rdi, TDX_MODULE_rdi(%rsi) +.endif /* \saved */ + /* Copy output registers to the structure */ movq %rcx, TDX_MODULE_rcx(%rsi) movq %rdx, TDX_MODULE_rdx(%rsi) @@ -73,17 +140,61 @@ movq %r9, TDX_MODULE_r9(%rsi) movq %r10, TDX_MODULE_r10(%rsi) movq %r11, TDX_MODULE_r11(%rsi) -.endif +.endif /* \ret */ + +.if \host && \saved && \ret + /* + * Clear registers shared by guest for VP.ENTER to prevent + * speculative use of guest's values, including those are + * restored from the stack. + * + * See arch/x86/kvm/vmx/vmenter.S: + * + * In theory, a L1 cache miss when restoring register from stack + * could lead to speculative execution with guest's values. + * + * Note: RBP/RSP are not used as shared register. RSI has been + * restored already. + * + * XOR is cheap, thus unconditionally do for all leafs. + */ + xorl %ecx, %ecx + xorl %edx, %edx + xorl %r8d, %r8d + xorl %r9d, %r9d + xorl %r10d, %r10d + xorl %r11d, %r11d + xorl %r12d, %r12d + xorl %r13d, %r13d + xorl %r14d, %r14d + xorl %r15d, %r15d + xorl %ebx, %ebx + xorl %edi, %edi +.endif /* \host && \ret && \host */ =20 .if \host .Lout\@: .endif + +.if \saved + /* Restore callee-saved GPRs as mandated by the x86_64 ABI */ + popq %r15 + popq %r14 + popq %r13 + popq %r12 + popq %rbx +.endif /* \saved */ + FRAME_END RET =20 .if \host .Lseamcall_vmfailinvalid\@: mov $TDX_SEAMCALL_VMFAILINVALID, %rax +.if \ret && \saved + /* pop the unused structure pointer back to RSI */ + popq %rsi +.endif jmp .Lout\@ .endif /* \host */ =20 --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 5D7FAC04FE2 for ; Tue, 15 Aug 2023 11:03:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236629AbjHOLDK (ORCPT ); Tue, 15 Aug 2023 07:03:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236571AbjHOLCp (ORCPT ); Tue, 15 Aug 2023 07:02:45 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71542B3 for ; Tue, 15 Aug 2023 04:02:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692097363; x=1723633363; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Si6s9dWiJIU8YztsDtdxHSJ1OGfJRh9b3rUVjtbbtn0=; b=g5cSJL+BXLfrRR/74YZ2UraagmBR0deN+5/69cSR8cEq5THS4cJJDOLe dPiTAXb0dbwZXJ3YzKS56xIprfew++wi4126qOoDPLKsrdauL57W5upej tUjsGCro2uc+GSCjmzD1UzoXJkW5tnDDKZoCr3XWrE4RG4eyYlwImzp2i OgQ3NNB2taEo5hzgqsmkaN7HqtoB3l13llrHEiBXfw/33x8BRV+wG65C5 P1XjOk63TNuZ1VR5ldctU9mdIy3cq/RjZK6nhDVnoz7Kwi1rUsMWPtE+x PLtXOpQQTbUCY0zO6pUrpbHCZe/9emrCVFq/nWdLmMr44rNQ9w/B5cOEu A==; X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148336" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148336" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236164" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236164" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:39 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 07/12] x86/tdx: Make TDX_HYPERCALL asm similar to TDX_MODULE_CALL Date: Tue, 15 Aug 2023 23:02:01 +1200 Message-ID: <0cbf25e7aee3256288045023a31f65f0cef90af4.1692096753.git.kai.huang@intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Now the 'struct tdx_hypercall_args' and 'struct tdx_module_args' are almost the same, and the TDX_HYPERCALL and TDX_MODULE_CALL asm macro share similar code pattern too. The __tdx_hypercall() and __tdcall() should be unified to use the same assembly code. As a preparation to unify them, simplify the TDX_HYPERCALL to make it more like the TDX_MODULE_CALL. The TDX_HYPERCALL takes the pointer of 'struct tdx_hypercall_args' as function call argument, and does below extra things comparing to the TDX_MODULE_CALL: 1) It sets RAX to 0 (TDG.VP.VMCALL leaf) internally; 2) It sets RCX to the (fixed) bitmap of shared registers internally; 3) It calls __tdx_hypercall_failed() internally (and panics) when the TDCALL instruction itself fails; 4) After TDCALL, it moves R10 to RAX to return the return code of the VMCALL leaf, regardless the '\ret' asm macro argument; Firstly, change the TDX_HYPERCALL to take the same function call arguments as the TDX_MODULE_CALL does: TDCALL leaf ID, and the pointer to 'struct tdx_module_args'. Then 1) and 2) can be moved to the caller: - TDG.VP.VMCALL leaf ID can be passed via the function call argument; - 'struct tdx_module_args' is 'struct tdx_hypercall_args' + RCX, thus the bitmap of shared registers can be passed via RCX in the structure. Secondly, to move 3) and 4) out of assembly, make the TDX_HYPERCALL always save output registers to the structure. The caller then can: - Call __tdx_hypercall_failed() when TDX_HYPERCALL returns error; - Return R10 in the structure as the return code of the VMCALL leaf; With above changes, change the asm function from __tdx_hypercall() to __tdcall_hypercall(), and reimplement __tdx_hypercall() as the C wrapper of it. This avoids having to add another wrapper of __tdx_hypercall() (_tdx_hypercall() is already taken). The __tdcall_hypercall() will be replaced with a __tdcall() variant using TDX_MODULE_CALL in a later commit as the final goal is to have one assembly to handle both TDCALL and TDVMCALL. Currently, the __tdx_hypercall() asm is in '.noinstr.text'. To keep this unchanged, annotate __tdx_hypercall(), which is a C function now, as 'noinstr'. Remove the __tdx_hypercall_ret() as __tdx_hypercall() already does so. Implement __tdx_hypercall() in tdx-shared.c so it can be shared with the compressed code. Opportunistically fix a checkpatch error complaining using space around parenthesis '(' and ')' while moving the bitmap of shared registers to . Cc: Kirill A. Shutemov Cc: Dave Hansen Cc: Peter Zijlstra Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kirill A. Shutemov --- v3 -> v4: - Annotate 'tdx_hypercall_failed' with __noreturn. - Removed uneeded header file inclusion. v2 -> v3: - Fixed 'noinstr' check build regression by annotating __tdx_hypercall() as 'noinstr'. - Slight update in changelog accordingly. v1 -> v2: - The first patch (major) split from v1 "x86/tdx: Unify TDX_HYPERCALL and TDX_MODULE_CALL assembly" - Rebase to 6.5-rc2. - Removed 'noinstr' and 'instrumentation_begin()' in __tdx_hypercall_failed(). - Minor improvement in comments and changelog. --- arch/x86/boot/compressed/tdx.c | 2 +- arch/x86/coco/tdx/tdcall.S | 146 ++++++++++-------------------- arch/x86/coco/tdx/tdx-shared.c | 43 +++++++++ arch/x86/coco/tdx/tdx.c | 11 ++- arch/x86/include/asm/shared/tdx.h | 86 ++++++++++++------ arch/x86/kernel/asm-offsets.c | 14 --- 6 files changed, 155 insertions(+), 147 deletions(-) diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c index 8841b945a1e2..bc03eae2c560 100644 --- a/arch/x86/boot/compressed/tdx.c +++ b/arch/x86/boot/compressed/tdx.c @@ -26,7 +26,7 @@ static inline unsigned int tdx_io_in(int size, u16 port) .r14 =3D port, }; =20 - if (__tdx_hypercall_ret(&args)) + if (__tdx_hypercall(&args)) return UINT_MAX; =20 return args.r11; diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index faf731d2b66a..6d76d7d49b72 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -2,41 +2,12 @@ #include #include #include -#include =20 #include -#include #include =20 #include "../../virt/vmx/tdx/tdxcall.S" =20 -/* - * Bitmasks of exposed registers (with VMM). - */ -#define TDX_RDX BIT(2) -#define TDX_RBX BIT(3) -#define TDX_RSI BIT(6) -#define TDX_RDI BIT(7) -#define TDX_R8 BIT(8) -#define TDX_R9 BIT(9) -#define TDX_R10 BIT(10) -#define TDX_R11 BIT(11) -#define TDX_R12 BIT(12) -#define TDX_R13 BIT(13) -#define TDX_R14 BIT(14) -#define TDX_R15 BIT(15) - -/* - * These registers are clobbered to hold arguments for each - * TDVMCALL. They are safe to expose to the VMM. - * Each bit in this mask represents a register ID. Bit field - * details can be found in TDX GHCI specification, section - * titled "TDCALL [TDG.VP.VMCALL] leaf". - */ -#define TDVMCALL_EXPOSE_REGS_MASK \ - ( TDX_RDX | TDX_RBX | TDX_RSI | TDX_RDI | TDX_R8 | TDX_R9 | \ - TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15 ) - .section .noinstr.text, "ax" =20 /* @@ -78,10 +49,13 @@ SYM_FUNC_END(__tdcall_ret) * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDC= ALL * instruction * - * Transforms values in function call argument struct tdx_hypercall_args = @args + * Transforms values in function call argument struct tdx_module_args @ar= gs * into the TDCALL register ABI. After TDCALL operation, VMM output is sav= ed * back in @args, if \ret is 1. * + * Depends on the caller to pass TDG.VP.VMCALL as the TDCALL leaf, and set + * @args::rcx to TDVMCALL_EXPOSE_REGS_MASK. + * *------------------------------------------------------------------------- * TD VMCALL ABI: *------------------------------------------------------------------------- @@ -106,7 +80,7 @@ SYM_FUNC_END(__tdcall_ret) * R8-R15 - Same as above. * */ -.macro TDX_HYPERCALL ret:req +.macro TDX_HYPERCALL FRAME_BEGIN =20 /* Save callee-saved GPRs as mandated by the x86_64 ABI */ @@ -116,63 +90,52 @@ SYM_FUNC_END(__tdcall_ret) push %r12 push %rbx =20 - /* Free RDI to be used as TDVMCALL arguments */ + /* Move Leaf ID to RAX */ movq %rdi, %rax =20 + /* Move bitmap of shared registers to RCX */ + movq TDX_MODULE_rcx(%rsi), %rcx + /* Copy hypercall registers from arg struct: */ - movq TDX_HYPERCALL_r8(%rax), %r8 - movq TDX_HYPERCALL_r9(%rax), %r9 - movq TDX_HYPERCALL_r10(%rax), %r10 - movq TDX_HYPERCALL_r11(%rax), %r11 - movq TDX_HYPERCALL_r12(%rax), %r12 - movq TDX_HYPERCALL_r13(%rax), %r13 - movq TDX_HYPERCALL_r14(%rax), %r14 - movq TDX_HYPERCALL_r15(%rax), %r15 - movq TDX_HYPERCALL_rdi(%rax), %rdi - movq TDX_HYPERCALL_rsi(%rax), %rsi - movq TDX_HYPERCALL_rbx(%rax), %rbx - movq TDX_HYPERCALL_rdx(%rax), %rdx + movq TDX_MODULE_r8(%rsi), %r8 + movq TDX_MODULE_r9(%rsi), %r9 + movq TDX_MODULE_r10(%rsi), %r10 + movq TDX_MODULE_r11(%rsi), %r11 + movq TDX_MODULE_r12(%rsi), %r12 + movq TDX_MODULE_r13(%rsi), %r13 + movq TDX_MODULE_r14(%rsi), %r14 + movq TDX_MODULE_r15(%rsi), %r15 + movq TDX_MODULE_rdi(%rsi), %rdi + movq TDX_MODULE_rbx(%rsi), %rbx + movq TDX_MODULE_rdx(%rsi), %rdx =20 - push %rax - - /* Mangle function call ABI into TDCALL ABI: */ - /* Set TDCALL leaf ID (TDVMCALL (0)) in RAX */ - xor %eax, %eax - - movl $TDVMCALL_EXPOSE_REGS_MASK, %ecx + pushq %rsi + movq TDX_MODULE_rsi(%rsi), %rsi =20 tdcall =20 /* - * RAX!=3D0 indicates a failure of the TDVMCALL mechanism itself and that - * something has gone horribly wrong with the TDX module. + * Restore the pointer of the structure to save output registers. * - * The return status of the hypercall operation is in a separate - * register (in R10). Hypercall errors are a part of normal operation - * and are handled by callers. + * RCX is used as bitmap of shared registers and doesn't hold any + * value provided by the VMM, thus it can be used as spare to + * restore the structure pointer. */ - testq %rax, %rax - jne .Lpanic\@ + popq %rcx + movq %rsi, TDX_MODULE_rsi(%rcx) + movq %rcx, %rsi =20 - pop %rax - - .if \ret - movq %r8, TDX_HYPERCALL_r8(%rax) - movq %r9, TDX_HYPERCALL_r9(%rax) - movq %r10, TDX_HYPERCALL_r10(%rax) - movq %r11, TDX_HYPERCALL_r11(%rax) - movq %r12, TDX_HYPERCALL_r12(%rax) - movq %r13, TDX_HYPERCALL_r13(%rax) - movq %r14, TDX_HYPERCALL_r14(%rax) - movq %r15, TDX_HYPERCALL_r15(%rax) - movq %rdi, TDX_HYPERCALL_rdi(%rax) - movq %rsi, TDX_HYPERCALL_rsi(%rax) - movq %rbx, TDX_HYPERCALL_rbx(%rax) - movq %rdx, TDX_HYPERCALL_rdx(%rax) - .endif - - /* TDVMCALL leaf return code is in R10 */ - movq %r10, %rax + movq %r8, TDX_MODULE_r8(%rsi) + movq %r9, TDX_MODULE_r9(%rsi) + movq %r10, TDX_MODULE_r10(%rsi) + movq %r11, TDX_MODULE_r11(%rsi) + movq %r12, TDX_MODULE_r12(%rsi) + movq %r13, TDX_MODULE_r13(%rsi) + movq %r14, TDX_MODULE_r14(%rsi) + movq %r15, TDX_MODULE_r15(%rsi) + movq %rdi, TDX_MODULE_rdi(%rsi) + movq %rbx, TDX_MODULE_rbx(%rsi) + movq %rdx, TDX_MODULE_rdx(%rsi) =20 /* * Zero out registers exposed to the VMM to avoid speculative execution @@ -198,33 +161,20 @@ SYM_FUNC_END(__tdcall_ret) FRAME_END =20 RET -.Lpanic\@: - call __tdx_hypercall_failed - /* __tdx_hypercall_failed never returns */ - REACHABLE - jmp .Lpanic\@ .endm =20 /* * - * __tdx_hypercall() function ABI: + * __tdcall_hypercall() function ABI: * - * @args (RDI) - struct tdx_hypercall_args for input + * @fn (RDI) - TDCALL leaf ID, moved to RAX + * @args (RSI) - struct tdx_module_args for input/output * - * On successful completion, return the hypercall error code. - */ -SYM_FUNC_START(__tdx_hypercall) - TDX_HYPERCALL ret=3D0 -SYM_FUNC_END(__tdx_hypercall) - -/* - * - * __tdx_hypercall_ret() function ABI: - * - * @args (RDI) - struct tdx_hypercall_args for input and output + * @fn and @args::rcx from the caller must be TDG_VP_VMCALL and + * TDVMCALL_EXPOSE_REGS_MASK respectively. * * On successful completion, return the hypercall error code. */ -SYM_FUNC_START(__tdx_hypercall_ret) - TDX_HYPERCALL ret=3D1 -SYM_FUNC_END(__tdx_hypercall_ret) +SYM_FUNC_START(__tdcall_hypercall) + TDX_HYPERCALL +SYM_FUNC_END(__tdcall_hypercall) diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index a7396d0ddef9..b47c8cce91b0 100644 --- a/arch/x86/coco/tdx/tdx-shared.c +++ b/arch/x86/coco/tdx/tdx-shared.c @@ -69,3 +69,46 @@ bool tdx_accept_memory(phys_addr_t start, phys_addr_t en= d) =20 return true; } + +noinstr u64 __tdx_hypercall(struct tdx_hypercall_args *args) +{ + struct tdx_module_args margs =3D { + .rcx =3D TDVMCALL_EXPOSE_REGS_MASK, + .rdx =3D args->rdx, + .r8 =3D args->r8, + .r9 =3D args->r9, + .r10 =3D args->r10, + .r11 =3D args->r11, + .r12 =3D args->r12, + .r13 =3D args->r13, + .r14 =3D args->r14, + .r15 =3D args->r15, + .rbx =3D args->rbx, + .rdi =3D args->rdi, + .rsi =3D args->rsi, + }; + + /* + * Failure of __tdcall_hypercall() indicates a failure of the TDVMCALL + * mechanism itself and that something has gone horribly wrong with + * the TDX module. __tdx_hypercall_failed() never returns. + */ + if (__tdcall_hypercall(TDG_VP_VMCALL, &margs)) + __tdx_hypercall_failed(); + + args->r8 =3D margs.r8; + args->r9 =3D margs.r9; + args->r10 =3D margs.r10; + args->r11 =3D margs.r11; + args->r12 =3D margs.r12; + args->r13 =3D margs.r13; + args->r14 =3D margs.r14; + args->r15 =3D margs.r15; + args->rdi =3D margs.rdi; + args->rsi =3D margs.rsi; + args->rbx =3D margs.rbx; + args->rdx =3D margs.rdx; + + /* TDVMCALL leaf return code is in R10 */ + return args->r10; +} diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 2e19cc62e59e..731d164e2421 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -38,7 +38,7 @@ #define TDREPORT_SUBTYPE_0 0 =20 /* Called from __tdx_hypercall() for unrecoverable failure */ -noinstr void __tdx_hypercall_failed(void) +noinstr void __noreturn __tdx_hypercall_failed(void) { instrumentation_begin(); panic("TDVMCALL failed. TDX module bug?"); @@ -285,7 +285,7 @@ static int read_msr(struct pt_regs *regs, struct ve_inf= o *ve) * can be found in TDX Guest-Host-Communication Interface * (GHCI), section titled "TDG.VP.VMCALL". */ - if (__tdx_hypercall_ret(&args)) + if (__tdx_hypercall(&args)) return -EIO; =20 regs->ax =3D lower_32_bits(args.r11); @@ -339,7 +339,7 @@ static int handle_cpuid(struct pt_regs *regs, struct ve= _info *ve) * ABI can be found in TDX Guest-Host-Communication Interface * (GHCI), section titled "VP.VMCALL". */ - if (__tdx_hypercall_ret(&args)) + if (__tdx_hypercall(&args)) return -EIO; =20 /* @@ -366,8 +366,9 @@ static bool mmio_read(int size, unsigned long addr, uns= igned long *val) .r15 =3D *val, }; =20 - if (__tdx_hypercall_ret(&args)) + if (__tdx_hypercall(&args)) return false; + *val =3D args.r11; return true; } @@ -500,7 +501,7 @@ static bool handle_in(struct pt_regs *regs, int size, i= nt port) * in TDX Guest-Host-Communication Interface (GHCI) section titled * "TDG.VP.VMCALL". */ - success =3D !__tdx_hypercall_ret(&args); + success =3D !__tdx_hypercall(&args); =20 /* Update part of the register affected by the emulated instruction */ regs->ax &=3D ~mask; diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/share= d/tdx.h index 4468988adec5..da5205daa53d 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -11,6 +11,7 @@ #define TDX_IDENT "IntelTDX " =20 /* TDX module Call Leaf IDs */ +#define TDG_VP_VMCALL 0 #define TDG_VP_INFO 1 #define TDG_VP_VEINFO_GET 3 #define TDG_MR_REPORT 4 @@ -24,8 +25,63 @@ #define TDVMCALL_MAP_GPA 0x10001 #define TDVMCALL_REPORT_FATAL_ERROR 0x10003 =20 +/* + * Bitmasks of exposed registers (with VMM). + */ +#define TDX_RDX BIT(2) +#define TDX_RBX BIT(3) +#define TDX_RSI BIT(6) +#define TDX_RDI BIT(7) +#define TDX_R8 BIT(8) +#define TDX_R9 BIT(9) +#define TDX_R10 BIT(10) +#define TDX_R11 BIT(11) +#define TDX_R12 BIT(12) +#define TDX_R13 BIT(13) +#define TDX_R14 BIT(14) +#define TDX_R15 BIT(15) + +/* + * These registers are clobbered to hold arguments for each + * TDVMCALL. They are safe to expose to the VMM. + * Each bit in this mask represents a register ID. Bit field + * details can be found in TDX GHCI specification, section + * titled "TDCALL [TDG.VP.VMCALL] leaf". + */ +#define TDVMCALL_EXPOSE_REGS_MASK \ + (TDX_RDX | TDX_RBX | TDX_RSI | TDX_RDI | TDX_R8 | TDX_R9 | \ + TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15) + #ifndef __ASSEMBLY__ =20 +/* + * Used in __tdcall*() to gather the input/output registers' values of the + * TDCALL instruction when requesting services from the TDX module. This i= s a + * software only structure and not part of the TDX module/VMM ABI + */ +struct tdx_module_args { + /* callee-clobbered */ + u64 rcx; + u64 rdx; + u64 r8; + u64 r9; + /* extra callee-clobbered */ + u64 r10; + u64 r11; + /* callee-saved + rdi/rsi */ + u64 r12; + u64 r13; + u64 r14; + u64 r15; + u64 rbx; + u64 rdi; + u64 rsi; +}; + +/* Used to communicate with the TDX module */ +u64 __tdcall(u64 fn, struct tdx_module_args *args); +u64 __tdcall_ret(u64 fn, struct tdx_module_args *args); + /* * Used in __tdx_hypercall() to pass down and get back registers' values of * the TDCALL instruction when requesting services from the VMM. @@ -48,8 +104,8 @@ struct tdx_hypercall_args { }; =20 /* Used to request services from the VMM */ +u64 __tdcall_hypercall(u64 fn, struct tdx_module_args *args); u64 __tdx_hypercall(struct tdx_hypercall_args *args); -u64 __tdx_hypercall_ret(struct tdx_hypercall_args *args); =20 /* * Wrapper for standard use of __tdx_hypercall with no output aside from @@ -73,34 +129,6 @@ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r= 13, u64 r14, u64 r15) /* Called from __tdx_hypercall() for unrecoverable failure */ void __tdx_hypercall_failed(void); =20 -/* - * Used in __tdcall*() to gather the input/output registers' values of the - * TDCALL instruction when requesting services from the TDX module. This i= s a - * software only structure and not part of the TDX module/VMM ABI - */ -struct tdx_module_args { - /* callee-clobbered */ - u64 rcx; - u64 rdx; - u64 r8; - u64 r9; - /* extra callee-clobbered */ - u64 r10; - u64 r11; - /* callee-saved + rdi/rsi */ - u64 r12; - u64 r13; - u64 r14; - u64 r15; - u64 rbx; - u64 rdi; - u64 rsi; -}; - -/* Used to communicate with the TDX module */ -u64 __tdcall(u64 fn, struct tdx_module_args *args); -u64 __tdcall_ret(u64 fn, struct tdx_module_args *args); - bool tdx_accept_memory(phys_addr_t start, phys_addr_t end); =20 /* diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 1581564a67b7..6913b372ccf7 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -82,20 +82,6 @@ static void __used common(void) OFFSET(TDX_MODULE_rdi, tdx_module_args, rdi); OFFSET(TDX_MODULE_rsi, tdx_module_args, rsi); =20 - BLANK(); - OFFSET(TDX_HYPERCALL_r8, tdx_hypercall_args, r8); - OFFSET(TDX_HYPERCALL_r9, tdx_hypercall_args, r9); - OFFSET(TDX_HYPERCALL_r10, tdx_hypercall_args, r10); - OFFSET(TDX_HYPERCALL_r11, tdx_hypercall_args, r11); - OFFSET(TDX_HYPERCALL_r12, tdx_hypercall_args, r12); - OFFSET(TDX_HYPERCALL_r13, tdx_hypercall_args, r13); - OFFSET(TDX_HYPERCALL_r14, tdx_hypercall_args, r14); - OFFSET(TDX_HYPERCALL_r15, tdx_hypercall_args, r15); - OFFSET(TDX_HYPERCALL_rdi, tdx_hypercall_args, rdi); - OFFSET(TDX_HYPERCALL_rsi, tdx_hypercall_args, rsi); - OFFSET(TDX_HYPERCALL_rbx, tdx_hypercall_args, rbx); - OFFSET(TDX_HYPERCALL_rdx, tdx_hypercall_args, rdx); - BLANK(); OFFSET(BP_scratch, boot_params, scratch); OFFSET(BP_secure_boot, boot_params, secure_boot); --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 6C531C04FE1 for ; Tue, 15 Aug 2023 11:03:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236634AbjHOLDM (ORCPT ); Tue, 15 Aug 2023 07:03:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235059AbjHOLCr (ORCPT ); Tue, 15 Aug 2023 07:02:47 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1F06E6B for ; Tue, 15 Aug 2023 04:02:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692097366; x=1723633366; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=oIhEb8tGo0P/PlCuFOOOG6wjRMHQNz83TNd/+flu/TU=; b=FP5YRG8/9gZO1XjZEFvHVyioVB71jIhSOisX5iJgqQMyyFvFc5v1eOMl 8hvSHTdDnFdO7AyVn25rZlna9kk73rb9wgEgfbgcwLsU4kSfjs36i76on pAjxH1Ziywo/Xo2+pLNHgq2HG+sOYRZHyTw3HCEpePIW3NnhKYma45PWf /k2dZ7OZwst48oiM864FMb1+jo2La/ehOCVj5ovKF/Vtw+JGQrmxE9sqK HC0dKjxg3PyJLuwuyO/Gk5sKw20A13OV1+zKiD/fX7TjaadHgYPQg3Nq/ uDyjYBgY28VNmd1l0ibEY0Yao4RnSqwR7H4K1W15xwKDPkvAcXEud5jEI A==; X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148346" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148346" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236170" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236170" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:43 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 08/12] x86/tdx: Reimplement __tdx_hypercall() using TDX_MODULE_CALL asm Date: Tue, 15 Aug 2023 23:02:02 +1200 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Now the TDX_HYPERCALL asm is basically identical to the TDX_MODULE_CALL with both '\saved' and '\ret' enabled, with two minor things though: 1) The way to restore the structure pointer is different The TDX_HYPERCALL uses RCX as spare to restore the structure pointer, but the TDX_MODULE_CALL assumes no spare register can be used. In other words, TDX_MODULE_CALL already covers what TDX_HYPERCALL does. 2) TDX_MODULE_CALL only clears shared registers for TDH.VP.ENTER For this just need to make that code available for the non-host case. Thus, remove the TDX_HYPERCALL and reimplement the __tdx_hypercall() using the TDX_MODULE_CALL. Extend the TDX_MODULE_CALL to cover "clear shared registers" for TDG.VP.VMCALL. Introduce a new __tdcall_saved_ret() to replace the temporary __tdcall_hypercall(). The __tdcall_saved_ret() can also be used for those new TDCALLs which require more input/output registers than the basic TDCALLs do. Cc: Kirill A. Shutemov Cc: Dave Hansen Cc: Peter Zijlstra Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Reviewed-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) --- v3 -> v4: - Removed unneeded header file inclusion. - Added Kirill's Reviewed-by tag. v2 -> v3: - No update v1 -> v2: - The second patch (new) split from v1 "x86/tdx: Unify TDX_HYPERCALL and TDX_MODULE_CALL assembly" - Rebase to 6.5-rc2. --- arch/x86/coco/tdx/tdcall.S | 133 ++---------------------------- arch/x86/coco/tdx/tdx-shared.c | 4 +- arch/x86/include/asm/shared/tdx.h | 2 +- arch/x86/virt/vmx/tdx/tdxcall.S | 8 +- 4 files changed, 15 insertions(+), 132 deletions(-) diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index 6d76d7d49b72..52d9786da308 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -1,7 +1,6 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include #include -#include =20 #include #include @@ -46,135 +45,19 @@ SYM_FUNC_START(__tdcall_ret) SYM_FUNC_END(__tdcall_ret) =20 /* - * TDX_HYPERCALL - Make hypercalls to a TDX VMM using TDVMCALL leaf of TDC= ALL - * instruction + * __tdcall_saved_ret() - Used by TDX guests to request services from the + * TDX module (including VMM services) using TDCALL instruction, with + * saving output registers to the 'struct tdx_module_args' used as input. * - * Transforms values in function call argument struct tdx_module_args @ar= gs - * into the TDCALL register ABI. After TDCALL operation, VMM output is sav= ed - * back in @args, if \ret is 1. - * - * Depends on the caller to pass TDG.VP.VMCALL as the TDCALL leaf, and set - * @args::rcx to TDVMCALL_EXPOSE_REGS_MASK. - * - *------------------------------------------------------------------------- - * TD VMCALL ABI: - *------------------------------------------------------------------------- - * - * Input Registers: - * - * RAX - TDCALL instruction leaf number (0 - TDG.VP.VMCALL) - * RCX - BITMAP which controls which part of TD Guest GPR - * is passed as-is to the VMM and back. - * R10 - Set 0 to indicate TDCALL follows standard TDX ABI - * specification. Non zero value indicates vendor - * specific ABI. - * R11 - VMCALL sub function number - * RBX, RDX, RDI, RSI - Used to pass VMCALL sub function specific argumen= ts. - * R8-R9, R12-R15 - Same as above. - * - * Output Registers: - * - * RAX - TDCALL instruction status (Not related to hyperca= ll - * output). - * RBX, RDX, RDI, RSI - Hypercall sub function specific output values. - * R8-R15 - Same as above. - * - */ -.macro TDX_HYPERCALL - FRAME_BEGIN - - /* Save callee-saved GPRs as mandated by the x86_64 ABI */ - push %r15 - push %r14 - push %r13 - push %r12 - push %rbx - - /* Move Leaf ID to RAX */ - movq %rdi, %rax - - /* Move bitmap of shared registers to RCX */ - movq TDX_MODULE_rcx(%rsi), %rcx - - /* Copy hypercall registers from arg struct: */ - movq TDX_MODULE_r8(%rsi), %r8 - movq TDX_MODULE_r9(%rsi), %r9 - movq TDX_MODULE_r10(%rsi), %r10 - movq TDX_MODULE_r11(%rsi), %r11 - movq TDX_MODULE_r12(%rsi), %r12 - movq TDX_MODULE_r13(%rsi), %r13 - movq TDX_MODULE_r14(%rsi), %r14 - movq TDX_MODULE_r15(%rsi), %r15 - movq TDX_MODULE_rdi(%rsi), %rdi - movq TDX_MODULE_rbx(%rsi), %rbx - movq TDX_MODULE_rdx(%rsi), %rdx - - pushq %rsi - movq TDX_MODULE_rsi(%rsi), %rsi - - tdcall - - /* - * Restore the pointer of the structure to save output registers. - * - * RCX is used as bitmap of shared registers and doesn't hold any - * value provided by the VMM, thus it can be used as spare to - * restore the structure pointer. - */ - popq %rcx - movq %rsi, TDX_MODULE_rsi(%rcx) - movq %rcx, %rsi - - movq %r8, TDX_MODULE_r8(%rsi) - movq %r9, TDX_MODULE_r9(%rsi) - movq %r10, TDX_MODULE_r10(%rsi) - movq %r11, TDX_MODULE_r11(%rsi) - movq %r12, TDX_MODULE_r12(%rsi) - movq %r13, TDX_MODULE_r13(%rsi) - movq %r14, TDX_MODULE_r14(%rsi) - movq %r15, TDX_MODULE_r15(%rsi) - movq %rdi, TDX_MODULE_rdi(%rsi) - movq %rbx, TDX_MODULE_rbx(%rsi) - movq %rdx, TDX_MODULE_rdx(%rsi) - - /* - * Zero out registers exposed to the VMM to avoid speculative execution - * with VMM-controlled values. This needs to include all registers - * present in TDVMCALL_EXPOSE_REGS_MASK, except RBX, and R12-R15 which - * will be restored. - */ - xor %r8d, %r8d - xor %r9d, %r9d - xor %r10d, %r10d - xor %r11d, %r11d - xor %rdi, %rdi - xor %rsi, %rsi - xor %rdx, %rdx - - /* Restore callee-saved GPRs as mandated by the x86_64 ABI */ - pop %rbx - pop %r12 - pop %r13 - pop %r14 - pop %r15 - - FRAME_END - - RET -.endm - -/* - * - * __tdcall_hypercall() function ABI: + * __tdcall_saved_ret() function ABI: * * @fn (RDI) - TDCALL leaf ID, moved to RAX * @args (RSI) - struct tdx_module_args for input/output * - * @fn and @args::rcx from the caller must be TDG_VP_VMCALL and - * TDVMCALL_EXPOSE_REGS_MASK respectively. + * All registers in @args are used as input/output registers. * * On successful completion, return the hypercall error code. */ -SYM_FUNC_START(__tdcall_hypercall) - TDX_HYPERCALL -SYM_FUNC_END(__tdcall_hypercall) +SYM_FUNC_START(__tdcall_saved_ret) + TDX_MODULE_CALL host=3D0 ret=3D1 saved=3D1 +SYM_FUNC_END(__tdcall_saved_ret) diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index b47c8cce91b0..344b3818f4c3 100644 --- a/arch/x86/coco/tdx/tdx-shared.c +++ b/arch/x86/coco/tdx/tdx-shared.c @@ -89,11 +89,11 @@ noinstr u64 __tdx_hypercall(struct tdx_hypercall_args *= args) }; =20 /* - * Failure of __tdcall_hypercall() indicates a failure of the TDVMCALL + * Failure of __tdcall_saved_ret() indicates a failure of the TDVMCALL * mechanism itself and that something has gone horribly wrong with * the TDX module. __tdx_hypercall_failed() never returns. */ - if (__tdcall_hypercall(TDG_VP_VMCALL, &margs)) + if (__tdcall_saved_ret(TDG_VP_VMCALL, &margs)) __tdx_hypercall_failed(); =20 args->r8 =3D margs.r8; diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/share= d/tdx.h index da5205daa53d..188e8bf3332c 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -81,6 +81,7 @@ struct tdx_module_args { /* Used to communicate with the TDX module */ u64 __tdcall(u64 fn, struct tdx_module_args *args); u64 __tdcall_ret(u64 fn, struct tdx_module_args *args); +u64 __tdcall_saved_ret(u64 fn, struct tdx_module_args *args); =20 /* * Used in __tdx_hypercall() to pass down and get back registers' values of @@ -104,7 +105,6 @@ struct tdx_hypercall_args { }; =20 /* Used to request services from the VMM */ -u64 __tdcall_hypercall(u64 fn, struct tdx_module_args *args); u64 __tdx_hypercall(struct tdx_hypercall_args *args); =20 /* diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcal= l.S index c54ea009b241..3f0b83a9977e 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -142,10 +142,10 @@ movq %r11, TDX_MODULE_r11(%rsi) .endif /* \ret */ =20 -.if \host && \saved && \ret +.if \saved && \ret /* - * Clear registers shared by guest for VP.ENTER to prevent - * speculative use of guest's values, including those are + * Clear registers shared by guest for VP.VMCALL/VP.ENTER to prevent + * speculative use of guest's/VMM's values, including those are * restored from the stack. * * See arch/x86/kvm/vmx/vmenter.S: @@ -170,7 +170,7 @@ xorl %r15d, %r15d xorl %ebx, %ebx xorl %edi, %edi -.endif /* \host && \ret && \host */ +.endif /* \ret && \host */ =20 .if \host .Lout\@: --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 694E0C001E0 for ; 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X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148358" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148358" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:49 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236174" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236174" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:46 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 09/12] x86/tdx: Remove 'struct tdx_hypercall_args' Date: Tue, 15 Aug 2023 23:02:03 +1200 Message-ID: <798dad5ce24e9d745cf0e16825b75ccc433ad065.1692096753.git.kai.huang@intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Now 'struct tdx_hypercall_args' is basically 'struct tdx_module_args' minus RCX. Although from __tdx_hypercall()'s perspective RCX isn't used as shared register thus not part of input/output registers, it's not worth to have a separate structure just due to one register. Remove the 'struct tdx_hypercall_args' and use 'struct tdx_module_args' instead in __tdx_hypercall() related code. This also saves the memory copy between the two structures within __tdx_hypercall(). Cc: Kirill A. Shutemov Cc: Dave Hansen Cc: Peter Zijlstra Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Reviewed-by: Kirill A. Shutemov Acked-by: Peter Zijlstra (Intel) --- arch/x86/boot/compressed/tdx.c | 4 ++-- arch/x86/coco/tdx/tdx-shared.c | 37 ++++++------------------------- arch/x86/coco/tdx/tdx.c | 16 ++++++------- arch/x86/include/asm/shared/tdx.h | 25 ++------------------- 4 files changed, 19 insertions(+), 63 deletions(-) diff --git a/arch/x86/boot/compressed/tdx.c b/arch/x86/boot/compressed/tdx.c index bc03eae2c560..8451d6a1030c 100644 --- a/arch/x86/boot/compressed/tdx.c +++ b/arch/x86/boot/compressed/tdx.c @@ -18,7 +18,7 @@ void __tdx_hypercall_failed(void) =20 static inline unsigned int tdx_io_in(int size, u16 port) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D hcall_func(EXIT_REASON_IO_INSTRUCTION), .r12 =3D size, @@ -34,7 +34,7 @@ static inline unsigned int tdx_io_in(int size, u16 port) =20 static inline void tdx_io_out(int size, u16 port, u32 value) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D hcall_func(EXIT_REASON_IO_INSTRUCTION), .r12 =3D size, diff --git a/arch/x86/coco/tdx/tdx-shared.c b/arch/x86/coco/tdx/tdx-shared.c index 344b3818f4c3..78e413269791 100644 --- a/arch/x86/coco/tdx/tdx-shared.c +++ b/arch/x86/coco/tdx/tdx-shared.c @@ -70,45 +70,22 @@ bool tdx_accept_memory(phys_addr_t start, phys_addr_t e= nd) return true; } =20 -noinstr u64 __tdx_hypercall(struct tdx_hypercall_args *args) +noinstr u64 __tdx_hypercall(struct tdx_module_args *args) { - struct tdx_module_args margs =3D { - .rcx =3D TDVMCALL_EXPOSE_REGS_MASK, - .rdx =3D args->rdx, - .r8 =3D args->r8, - .r9 =3D args->r9, - .r10 =3D args->r10, - .r11 =3D args->r11, - .r12 =3D args->r12, - .r13 =3D args->r13, - .r14 =3D args->r14, - .r15 =3D args->r15, - .rbx =3D args->rbx, - .rdi =3D args->rdi, - .rsi =3D args->rsi, - }; + /* + * For TDVMCALL explicitly set RCX to the bitmap of shared registers. + * The caller isn't expected to set @args->rcx anyway. + */ + args->rcx =3D TDVMCALL_EXPOSE_REGS_MASK; =20 /* * Failure of __tdcall_saved_ret() indicates a failure of the TDVMCALL * mechanism itself and that something has gone horribly wrong with * the TDX module. __tdx_hypercall_failed() never returns. */ - if (__tdcall_saved_ret(TDG_VP_VMCALL, &margs)) + if (__tdcall_saved_ret(TDG_VP_VMCALL, args)) __tdx_hypercall_failed(); =20 - args->r8 =3D margs.r8; - args->r9 =3D margs.r9; - args->r10 =3D margs.r10; - args->r11 =3D margs.r11; - args->r12 =3D margs.r12; - args->r13 =3D margs.r13; - args->r14 =3D margs.r14; - args->r15 =3D margs.r15; - args->rdi =3D margs.rdi; - args->rsi =3D margs.rsi; - args->rbx =3D margs.rbx; - args->rdx =3D margs.rdx; - /* TDVMCALL leaf return code is in R10 */ return args->r10; } diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 731d164e2421..6311d843cbc5 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -48,7 +48,7 @@ noinstr void __noreturn __tdx_hypercall_failed(void) long tdx_kvm_hypercall(unsigned int nr, unsigned long p1, unsigned long p2, unsigned long p3, unsigned long p4) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D nr, .r11 =3D p1, .r12 =3D p2, @@ -108,7 +108,7 @@ EXPORT_SYMBOL_GPL(tdx_mcall_get_report0); =20 static void __noreturn tdx_panic(const char *msg) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D TDVMCALL_REPORT_FATAL_ERROR, .r12 =3D 0, /* Error code: 0 is Panic */ @@ -230,7 +230,7 @@ static int ve_instr_len(struct ve_info *ve) =20 static u64 __cpuidle __halt(const bool irq_disabled) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D hcall_func(EXIT_REASON_HLT), .r12 =3D irq_disabled, @@ -274,7 +274,7 @@ void __cpuidle tdx_safe_halt(void) =20 static int read_msr(struct pt_regs *regs, struct ve_info *ve) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D hcall_func(EXIT_REASON_MSR_READ), .r12 =3D regs->cx, @@ -295,7 +295,7 @@ static int read_msr(struct pt_regs *regs, struct ve_inf= o *ve) =20 static int write_msr(struct pt_regs *regs, struct ve_info *ve) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D hcall_func(EXIT_REASON_MSR_WRITE), .r12 =3D regs->cx, @@ -315,7 +315,7 @@ static int write_msr(struct pt_regs *regs, struct ve_in= fo *ve) =20 static int handle_cpuid(struct pt_regs *regs, struct ve_info *ve) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D hcall_func(EXIT_REASON_CPUID), .r12 =3D regs->ax, @@ -357,7 +357,7 @@ static int handle_cpuid(struct pt_regs *regs, struct ve= _info *ve) =20 static bool mmio_read(int size, unsigned long addr, unsigned long *val) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D hcall_func(EXIT_REASON_EPT_VIOLATION), .r12 =3D size, @@ -486,7 +486,7 @@ static int handle_mmio(struct pt_regs *regs, struct ve_= info *ve) =20 static bool handle_in(struct pt_regs *regs, int size, int port) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D hcall_func(EXIT_REASON_IO_INSTRUCTION), .r12 =3D size, diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/share= d/tdx.h index 188e8bf3332c..74fc466dfdcd 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -83,29 +83,8 @@ u64 __tdcall(u64 fn, struct tdx_module_args *args); u64 __tdcall_ret(u64 fn, struct tdx_module_args *args); u64 __tdcall_saved_ret(u64 fn, struct tdx_module_args *args); =20 -/* - * Used in __tdx_hypercall() to pass down and get back registers' values of - * the TDCALL instruction when requesting services from the VMM. - * - * This is a software only structure and not part of the TDX module/VMM AB= I. - */ -struct tdx_hypercall_args { - u64 r8; - u64 r9; - u64 r10; - u64 r11; - u64 r12; - u64 r13; - u64 r14; - u64 r15; - u64 rdi; - u64 rsi; - u64 rbx; - u64 rdx; -}; - /* Used to request services from the VMM */ -u64 __tdx_hypercall(struct tdx_hypercall_args *args); +u64 __tdx_hypercall(struct tdx_module_args *args); =20 /* * Wrapper for standard use of __tdx_hypercall with no output aside from @@ -113,7 +92,7 @@ u64 __tdx_hypercall(struct tdx_hypercall_args *args); */ static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r1= 5) { - struct tdx_hypercall_args args =3D { + struct tdx_module_args args =3D { .r10 =3D TDX_HYPERCALL_STANDARD, .r11 =3D fn, .r12 =3D r12, --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 EFE21C0015E for ; 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X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148375" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148375" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236179" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236179" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:49 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 10/12] x86/virt/tdx: Wire up basic SEAMCALL functions Date: Tue, 15 Aug 2023 23:02:04 +1200 Message-ID: <4db7c3fc085e6af12acc2932294254ddb3d320b3.1692096753.git.kai.huang@intel.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Intel Trust Domain Extensions (TDX) protects guest VMs from malicious host and certain physical attacks. A CPU-attested software module called 'the TDX module' runs inside a new isolated memory range as a trusted hypervisor to manage and run protected VMs. TDX introduces a new CPU mode: Secure Arbitration Mode (SEAM). This mode runs only the TDX module itself or other code to load the TDX module. The host kernel communicates with SEAM software via a new SEAMCALL instruction. This is conceptually similar to a guest->host hypercall, except it is made from the host to SEAM software instead. The TDX module establishes a new SEAMCALL ABI which allows the host to initialize the module and to manage VMs. The SEAMCALL ABI is very similar to the TDCALL ABI and leverages much TDCALL infrastructure. Wire up basic functions to make SEAMCALLs for the basic support of running TDX guests: __seamcall(), __seamcall_ret(), and __seamcall_saved_ret() for TDH.VP.ENTER. All SEAMCALLs involved in the basic TDX support don't use "callee-saved" registers as input and output, except the TDH.VP.ENTER. To start to support TDX, create a new arch/x86/virt/vmx/tdx/tdx.c for TDX host kernel support. Add a new Kconfig option CONFIG_INTEL_TDX_HOST to opt-in TDX host kernel support (to distinguish with TDX guest kernel support). So far only KVM uses TDX. Make the new config option depend on KVM_INTEL. Signed-off-by: Kai Huang Reviewed-by: Kirill A. Shutemov Tested-by: Isaku Yamahata Acked-by: Peter Zijlstra (Intel) --- arch/x86/Kconfig | 12 +++++++ arch/x86/Makefile | 2 ++ arch/x86/include/asm/tdx.h | 7 ++++ arch/x86/virt/Makefile | 2 ++ arch/x86/virt/vmx/Makefile | 2 ++ arch/x86/virt/vmx/tdx/Makefile | 2 ++ arch/x86/virt/vmx/tdx/seamcall.S | 61 ++++++++++++++++++++++++++++++++ 7 files changed, 88 insertions(+) create mode 100644 arch/x86/virt/Makefile create mode 100644 arch/x86/virt/vmx/Makefile create mode 100644 arch/x86/virt/vmx/tdx/Makefile create mode 100644 arch/x86/virt/vmx/tdx/seamcall.S diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 7422db409770..0558dd98abd7 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1949,6 +1949,18 @@ config X86_SGX =20 If unsure, say N. =20 +config INTEL_TDX_HOST + bool "Intel Trust Domain Extensions (TDX) host support" + depends on CPU_SUP_INTEL + depends on X86_64 + depends on KVM_INTEL + help + Intel Trust Domain Extensions (TDX) protects guest VMs from malicious + host and certain physical attacks. This option enables necessary TDX + support in the host kernel to run confidential VMs. + + If unsure, say N. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/arch/x86/Makefile b/arch/x86/Makefile index fdc2e3abd615..5d8d1892aae9 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -252,6 +252,8 @@ archheaders: =20 libs-y +=3D arch/x86/lib/ =20 +core-y +=3D arch/x86/virt/ + # drivers-y are linked after core-y drivers-$(CONFIG_MATH_EMULATION) +=3D arch/x86/math-emu/ drivers-$(CONFIG_PCI) +=3D arch/x86/pci/ diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index 603e6d1e9d4a..a69bb7d3061b 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -72,5 +72,12 @@ static inline long tdx_kvm_hypercall(unsigned int nr, un= signed long p1, return -ENODEV; } #endif /* CONFIG_INTEL_TDX_GUEST && CONFIG_KVM_GUEST */ + +#ifdef CONFIG_INTEL_TDX_HOST +u64 __seamcall(u64 fn, struct tdx_module_args *args); +u64 __seamcall_ret(u64 fn, struct tdx_module_args *args); +u64 __seamcall_saved_ret(u64 fn, struct tdx_module_args *args); +#endif /* CONFIG_INTEL_TDX_HOST */ + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_TDX_H */ diff --git a/arch/x86/virt/Makefile b/arch/x86/virt/Makefile new file mode 100644 index 000000000000..1e36502cd738 --- /dev/null +++ b/arch/x86/virt/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-y +=3D vmx/ diff --git a/arch/x86/virt/vmx/Makefile b/arch/x86/virt/vmx/Makefile new file mode 100644 index 000000000000..feebda21d793 --- /dev/null +++ b/arch/x86/virt/vmx/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_INTEL_TDX_HOST) +=3D tdx/ diff --git a/arch/x86/virt/vmx/tdx/Makefile b/arch/x86/virt/vmx/tdx/Makefile new file mode 100644 index 000000000000..46ef8f73aebb --- /dev/null +++ b/arch/x86/virt/vmx/tdx/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-y +=3D seamcall.o diff --git a/arch/x86/virt/vmx/tdx/seamcall.S b/arch/x86/virt/vmx/tdx/seamc= all.S new file mode 100644 index 000000000000..5b1f2286aea9 --- /dev/null +++ b/arch/x86/virt/vmx/tdx/seamcall.S @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include +#include + +#include "tdxcall.S" + +/* + * __seamcall() - Host-side interface functions to SEAM software + * (the P-SEAMLDR or the TDX module). + * + * __seamcall() function ABI: + * + * @fn (RDI) - SEAMCALL Leaf number, moved to RAX + * @args (RSI) - struct tdx_module_args for input + * + * Only RCX/RDX/R8-R11 are used as input registers. + * + * Return (via RAX) TDX_SEAMCALL_VMFAILINVALID if the SEAMCALL itself + * fails, or the completion status of the SEAMCALL leaf function. + */ +SYM_FUNC_START(__seamcall) + TDX_MODULE_CALL host=3D1 +SYM_FUNC_END(__seamcall) + +/* + * __seamcall_ret() - Host-side interface functions to SEAM software + * (the P-SEAMLDR or the TDX module), with saving output registers to + * the 'struct tdx_module_args' used as input. + * + * __seamcall_ret() function ABI: + * + * @fn (RDI) - SEAMCALL Leaf number, moved to RAX + * @args (RSI) - struct tdx_module_args for input and output + * + * Only RCX/RDX/R8-R11 are used as input/output registers. + * + * Return (via RAX) TDX_SEAMCALL_VMFAILINVALID if the SEAMCALL itself + * fails, or the completion status of the SEAMCALL leaf function. + */ +SYM_FUNC_START(__seamcall_ret) + TDX_MODULE_CALL host=3D1 ret=3D1 +SYM_FUNC_END(__seamcall_ret) + +/* + * __seamcall_saved_ret() - Host-side interface functions to SEAM software + * (the P-SEAMLDR or the TDX module), with saving output registers to the + * 'struct tdx_module_args' used as input. + * + * __seamcall_saved_ret() function ABI: + * + * @fn (RDI) - SEAMCALL Leaf number, moved to RAX + * @args (RSI) - struct tdx_module_args for input and output + * + * All registers in @args are used as input/output registers. + * + * Return (via RAX) TDX_SEAMCALL_VMFAILINVALID if the SEAMCALL itself + * fails, or the completion status of the SEAMCALL leaf function. + */ +SYM_FUNC_START(__seamcall_saved_ret) + TDX_MODULE_CALL host=3D1 ret=3D1 saved=3D1 +SYM_FUNC_END(__seamcall_saved_ret) --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 04EC1C04A6A for ; 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X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148398" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148398" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236183" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236183" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:53 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 11/12] x86/virt/tdx: Make TDX_MODULE_CALL handle SEAMCALL #UD and #GP Date: Tue, 15 Aug 2023 23:02:05 +1200 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" SEAMCALL instruction causes #UD if the CPU isn't in VMX operation. Currently the TDX_MODULE_CALL assembly doesn't handle #UD, thus making SEAMCALL when VMX is disabled would cause Oops. Unfortunately, there are legal cases that SEAMCALL can be made when VMX is disabled. For instance, VMX can be disabled due to emergency reboot while there are still TDX guests running. Extend the TDX_MODULE_CALL assembly to return an error code for #UD to handle this case gracefully, e.g., KVM can then quietly eat all SEAMCALL errors caused by emergency reboot. SEAMCALL instruction also causes #GP when TDX isn't enabled by the BIOS. Use _ASM_EXTABLE_FAULT() to catch both exceptions with the trap number recorded, and define two new error codes by XORing the trap number to the TDX_SW_ERROR. This opportunistically handles #GP too while using the same simple assembly code. A bonus is when kernel mistakenly calls SEAMCALL when CPU isn't in VMX operation, or when TDX isn't enabled by the BIOS, or when the BIOS is buggy, the kernel can get a nicer error code rather than a less understandable Oops. This is basically based on Peter's code. Cc: Kirill A. Shutemov Cc: Dave Hansen Cc: Peter Zijlstra Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Acked-by: Peter Zijlstra (Intel) Reviewed-by: Kirill A. Shutemov --- v3 -> v4: - Changed changelog to use emergency reboot as justification instead of the erratum. - Slight changed patch title to be more precise. =20 v2 -> v3: - Added more material to the changelog to explain the TDX erratum (hoping it can be merged together with this series). - Changed to use %rdi to hold $TDX_SW_ERROR instead of %r12 as the latter is callee-saved. v1 -> v2: - Skip saving output registers when SEAMCALL #UD/#GP --- arch/x86/include/asm/tdx.h | 4 ++++ arch/x86/virt/vmx/tdx/tdxcall.S | 19 +++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index a69bb7d3061b..adcbe3f1de30 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -8,6 +8,7 @@ =20 #include #include +#include #include =20 /* @@ -20,6 +21,9 @@ #define TDX_SW_ERROR (TDX_ERROR | GENMASK_ULL(47, 40)) #define TDX_SEAMCALL_VMFAILINVALID (TDX_SW_ERROR | _UL(0xFFFF0000)) =20 +#define TDX_SEAMCALL_GP (TDX_SW_ERROR | X86_TRAP_GP) +#define TDX_SEAMCALL_UD (TDX_SW_ERROR | X86_TRAP_UD) + #ifndef __ASSEMBLY__ =20 /* diff --git a/arch/x86/virt/vmx/tdx/tdxcall.S b/arch/x86/virt/vmx/tdx/tdxcal= l.S index 3f0b83a9977e..016a2a1ec1d6 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -1,6 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include #include +#include #include =20 /* @@ -85,6 +86,7 @@ .endif /* \saved */ =20 .if \host +.Lseamcall\@: seamcall /* * SEAMCALL instruction is essentially a VMExit from VMX root @@ -191,11 +193,28 @@ .if \host .Lseamcall_vmfailinvalid\@: mov $TDX_SEAMCALL_VMFAILINVALID, %rax + jmp .Lseamcall_fail\@ + +.Lseamcall_trap\@: + /* + * SEAMCALL caused #GP or #UD. By reaching here RAX contains + * the trap number. Convert the trap number to the TDX error + * code by setting TDX_SW_ERROR to the high 32-bits of RAX. + * + * Note cannot OR TDX_SW_ERROR directly to RAX as OR instruction + * only accepts 32-bit immediate at most. + */ + movq $TDX_SW_ERROR, %rdi + orq %rdi, %rax + +.Lseamcall_fail\@: .if \ret && \saved /* pop the unused structure pointer back to RSI */ popq %rsi .endif jmp .Lout\@ + + _ASM_EXTABLE_FAULT(.Lseamcall\@, .Lseamcall_trap\@) .endif /* \host */ =20 .endm --=20 2.41.0 From nobody Tue Dec 16 03:20:12 2025 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 14729C41513 for ; Tue, 15 Aug 2023 11:04:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236687AbjHOLDx (ORCPT ); Tue, 15 Aug 2023 07:03:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39300 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236612AbjHOLDB (ORCPT ); Tue, 15 Aug 2023 07:03:01 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A8FBE6B for ; Tue, 15 Aug 2023 04:03:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1692097380; x=1723633380; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=KfA+OEQel2hlB9E3+pafaAI8n8ikzj6Tz1k0C8sfZTY=; b=a/7WHoUTJ1lMJ99aEzvj8VY9ZpFVUdyT1nBwIbQtsnNO3SWT+fH3DYdL HS46cvnysczqKhJwO+JIuzEHYgwrf4Cs+c5lY+MMd65zF6Bk9XFhPytAX VGh03JlJQUIR14kD4pMy/zSsZrhAQJ/CyTPoO//SanhOLOIAIxQATfoAK LkiZltCG7/OYWS8B5xoO4htwBdOgcETi06wXpL0ObB8URgBLCqxlPTdt2 Qz1tc6P714sL4ZKAOxACEM70Dc6/LlaBi4Fz5mvwutpOrCCvhmTLI6pa1 TL7IxzdjpTbpaUcasfOpyX1OHS7rB21rzJ9M089zyJTL5iR2Q2f/cpa8V w==; X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436148416" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436148416" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:03:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763236187" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763236187" Received: from fwafula-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.212.73.197]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2023 04:02:56 -0700 From: Kai Huang To: peterz@infradead.org, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org Cc: dave.hansen@intel.com, tglx@linutronix.de, bp@alien8.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, n.borisov.lkml@gmail.com, kai.huang@intel.com Subject: [PATCH v4 12/12] x86/virt/tdx: Adjust 'struct tdx_module_args' to use x86 "register index" layout Date: Tue, 15 Aug 2023 23:02:06 +1200 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" For TDX guest, KVM needs to call __seamcall_saved_ret() to make the TDH.VP.ENTER SEAMCALL to enter the guest, possibly taking all registers in 'struct tdx_module_args' as input/output. KVM caches guest's GPRs in 'kvm_vcpu_arch::regs[]', which follows the "register index" hardware layout of x86 GPRs. On the other hand, the __seamcall_saved_ret() takes the pointer of 'struct tdx_module_args' as argument, thus there's a mismatch. KVM could choose to copy input registers from 'vcpu::regs[]' to a 'struct tdx_module_args' and use that as argument to make the SEAMCALL, but such memory copy isn't desired and should be avoided if possible. It's not feasible to change KVM's 'vcpu::regs[]' layout due to various reasons (e.g., emulation code uses decoded register index as array index to access the register). Therefore, adjust 'struct tdx_module_args' to match KVM's 'vcpu::regs[]' layout so that KVM can simply do below: __seamcall_saved_ret(TDH_VP_ENTER, (struct tdx_module_args *)vcpu->arch.regs); Note RAX/RSP/RBP are not used by the TDX_MODULE_CALL assembly, but they are necessary in order to match the layout of 'struct tdx_module_args' to KVM's 'vcpu::regs[]'. Thus add them to the structure, but name them as *_unused. Also don't include them to asm-offset.c so that any misuse of them in the assembly would result in build error. Cc: Kirill A. Shutemov Cc: Dave Hansen Cc: Peter Zijlstra Cc: Sean Christopherson Cc: Paolo Bonzini Cc: Isaku Yamahata Suggested-by: Peter Zijlstra Signed-off-by: Kai Huang Tested-by: Isaku Yamahata Acked-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/shared/tdx.h | 19 +++++++++++++------ arch/x86/kernel/asm-offsets.c | 6 +++--- 2 files changed, 16 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/share= d/tdx.h index 74fc466dfdcd..8d1427562c63 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -58,24 +58,31 @@ * Used in __tdcall*() to gather the input/output registers' values of the * TDCALL instruction when requesting services from the TDX module. This i= s a * software only structure and not part of the TDX module/VMM ABI + * + * Note those *_unused are not used by the TDX_MODULE_CALL assembly. + * The layout of this structure also matches KVM's kvm_vcpu_arch::regs[] + * layout, which follows the "register index" order of x86 GPRs. KVM + * then can simply type cast kvm_vcpu_arch::regs[] to this structure to + * avoid the extra memory copy between two structures when making + * TDH.VP.ENTER SEAMCALL. */ struct tdx_module_args { - /* callee-clobbered */ + u64 rax_unused; u64 rcx; u64 rdx; + u64 rbx; + u64 rsp_unused; + u64 rbp_unused; + u64 rsi; + u64 rdi; u64 r8; u64 r9; - /* extra callee-clobbered */ u64 r10; u64 r11; - /* callee-saved + rdi/rsi */ u64 r12; u64 r13; u64 r14; u64 r15; - u64 rbx; - u64 rdi; - u64 rsi; }; =20 /* Used to communicate with the TDX module */ diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 6913b372ccf7..e4ad822d3acd 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -70,6 +70,9 @@ static void __used common(void) BLANK(); OFFSET(TDX_MODULE_rcx, tdx_module_args, rcx); OFFSET(TDX_MODULE_rdx, tdx_module_args, rdx); + OFFSET(TDX_MODULE_rbx, tdx_module_args, rbx); + OFFSET(TDX_MODULE_rsi, tdx_module_args, rsi); + OFFSET(TDX_MODULE_rdi, tdx_module_args, rdi); OFFSET(TDX_MODULE_r8, tdx_module_args, r8); OFFSET(TDX_MODULE_r9, tdx_module_args, r9); OFFSET(TDX_MODULE_r10, tdx_module_args, r10); @@ -78,9 +81,6 @@ static void __used common(void) OFFSET(TDX_MODULE_r13, tdx_module_args, r13); OFFSET(TDX_MODULE_r14, tdx_module_args, r14); OFFSET(TDX_MODULE_r15, tdx_module_args, r15); - OFFSET(TDX_MODULE_rbx, tdx_module_args, rbx); - OFFSET(TDX_MODULE_rdi, tdx_module_args, rdi); - OFFSET(TDX_MODULE_rsi, tdx_module_args, rsi); =20 BLANK(); OFFSET(BP_scratch, boot_params, scratch); --=20 2.41.0