From nobody Tue Dec 16 11:50:09 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 17FA5EB64DD for ; Wed, 12 Jul 2023 08:56:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233105AbjGLI4g (ORCPT ); Wed, 12 Jul 2023 04:56:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47204 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232995AbjGLI4M (ORCPT ); Wed, 12 Jul 2023 04:56:12 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F0641BFA; Wed, 12 Jul 2023 01:56:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689152160; x=1720688160; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=0jmIeDORn+BMdd9A4WMNT2APZizZ1It678+a9F5J7Dg=; b=O9IKDU/8Yy0L117tuTVhNIaBLP8cbbnbvv1cEtX4wmT9dPI5086upInE dvvjKCSb8Jk252unvrvQKjbKGg7H8knVHGRdxrDIFGPUpJxuPNo3xIPRD knZWARaOctkt8R7gfCT7cYxQUX1fvXJxu97m9CZ7qaJ5kYKWK+wOnlVdJ 3baxMCpv2Ae3OVAv1P3i1aLLkx3YO7hzUFcI8HBSZC40tC+iQkLyFut5z IE2DS930yLTN1FuUx/MFJq+v7SsBKECCu58HeFC7WdnMORZ9Cng2OEOeE UtA6Z6IFDoFaJAsMrDPz9OLPlXoN6FM1gfx8atytaSMpOQP1PGDYBBOoo g==; X-IronPort-AV: E=McAfee;i="6600,9927,10768"; a="344439223" X-IronPort-AV: E=Sophos;i="6.01,199,1684825200"; d="scan'208";a="344439223" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jul 2023 01:55:59 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10768"; a="845573387" X-IronPort-AV: E=Sophos;i="6.01,199,1684825200"; d="scan'208";a="845573387" Received: from mjamatan-mobl2.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.209.168.102]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Jul 2023 01:55:55 -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, kvm@vger.kernel.org, isaku.yamahata@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, kai.huang@intel.com Subject: [PATCH 06/10] x86/tdx: Pass TDCALL/SEAMCALL input/output registers via a structure Date: Wed, 12 Jul 2023 20:55:20 +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" 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, 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' parameter to indicate whether to save the additional 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 --- arch/x86/coco/tdx/tdcall.S | 48 ++++++++----------- arch/x86/coco/tdx/tdx.c | 50 +++++++++++--------- arch/x86/include/asm/tdx.h | 10 ++-- arch/x86/kernel/asm-offsets.c | 12 ++--- arch/x86/virt/vmx/tdx/tdxcall.S | 82 +++++++++++++-------------------- 5 files changed, 89 insertions(+), 113 deletions(-) diff --git a/arch/x86/coco/tdx/tdcall.S b/arch/x86/coco/tdx/tdcall.S index 6aebac08f2bf..46847e85c372 100644 --- a/arch/x86/coco/tdx/tdcall.S +++ b/arch/x86/coco/tdx/tdcall.S @@ -43,44 +43,32 @@ * __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. */ SYM_FUNC_START(__tdcall) - TDX_MODULE_CALL host=3D0 + TDX_MODULE_CALL host=3D0 ret=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. + * + * __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.c b/arch/x86/coco/tdx/tdx.c index 268f812ff595..0f16ba52ae62 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -98,10 +98,9 @@ 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 @@ -121,11 +120,14 @@ static inline void tdcall(u64 fn, u64 rcx, u64 rdx, u= 64 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; @@ -173,7 +175,7 @@ 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 @@ -184,7 +186,7 @@ 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. @@ -193,7 +195,7 @@ 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 /* @@ -201,7 +203,7 @@ 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 @@ -609,7 +611,7 @@ __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 @@ -626,15 +628,15 @@ 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 /* @@ -738,7 +740,7 @@ static bool try_accept_one(phys_addr_t *start, unsigned= 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)) @@ -767,8 +769,8 @@ static bool try_accept_one(phys_addr_t *start, unsigned= long len, return false; } =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 false; =20 *start +=3D accept_size; @@ -855,6 +857,10 @@ 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 @@ -870,7 +876,7 @@ 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/tdx.h b/arch/x86/include/asm/tdx.h index f19e329c4044..e353c7ec5f24 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -21,16 +21,18 @@ #ifndef __ASSEMBLY__ =20 /* - * Used to gather the output registers values of the TDCALL and SEAMCALL + * Used to gather input/output registers of the TDCALL and SEAMCALL * instructions when requesting services from the TDX module. * * This is a software only structure and not part of the TDX module/VMM AB= I. */ -struct tdx_module_output { +struct tdx_module_args { + /* input/output */ u64 rcx; u64 rdx; u64 r8; u64 r9; + /* additional output */ u64 r10; u64 r11; }; @@ -56,8 +58,8 @@ struct ve_info { void __init tdx_early_init(void); =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 void tdx_get_ve_info(struct ve_info *ve); =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 b5ab919c7fa8..0af1374ad8f5 100644 --- a/arch/x86/virt/vmx/tdx/tdxcall.S +++ b/arch/x86/virt/vmx/tdx/tdxcall.S @@ -17,34 +17,33 @@ * 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-R9 - 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: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 - * 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 =20 .if \host seamcall @@ -65,34 +64,15 @@ 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 .Lno_output_struct - - /* 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) - -.Lno_output_struct: - /* Restore the state of R12 register */ - pop %r12 + .if \ret + /* Copy output regs 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 =20 FRAME_END RET --=20 2.41.0