From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5380833B6E0; Wed, 28 Jan 2026 23:54:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.21 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769644482; cv=none; b=PQf9XNnNwmqPdLK01HthJ3Jag4JeUao351yEBUbcR2LwliZZm5U1MhQsKEDpxsEDUoQZdLdl0C+nOCq3o34oi4pjg5jlSmsUN0t35/vZiAS/ux58NVy0oxy9lVnMhBg5haAOeGEyBrbtoYmuk1M4tWwR15gbrPqTHmulHRM1O1g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769644482; c=relaxed/simple; bh=0Cps4VFJ+P+DErVNWpvKHm3iAAy6qEtS67CdVWyN6oI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=J/Eppx6cEb/cO/YtK+3fpqrgm1LR30vnXcRUssjV0/D3uCYsqH4Pg75n+SsTrHnMBAi06lY5to2Chqcsg3zFUPzfaS2dwMb7bB57h4KoNGQMfMpM0g/qEbp+kHwDomqQ8rG5ukpECk6pKEBchhC/uwkpV3L9ZqpdSO5qnzWvjK4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Lrr1nAbR; arc=none smtp.client-ip=198.175.65.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Lrr1nAbR" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1769644481; x=1801180481; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=0Cps4VFJ+P+DErVNWpvKHm3iAAy6qEtS67CdVWyN6oI=; b=Lrr1nAbR6v2XDulcdGsxkER0z1vUoJZ8NMugAN9F1NzZs1A7hdOY//Yu 4rbfw6Dsv/TyQCee7Pc2cVASnXvkzHQm9nuQJ3abbyUQ/nP2lz1ZVgrOd QCTKaSHrQVgsXYjxw66kw05PzlkkBBp+NRwxoTu9yina0LyKoMMbqJJFO eIz0Pv147g+aXI6HgUUMYeFoKcCMpn8b2a0VCUfIw7ln/w3N5cj1uavBc k2w+i78BOS+0spg49oOSglh7VYSYZN1cITcqYsBWG+zi/h1iUWMxlmfGm xN31W4nG3A2iF+hREUZixnMqZcAzuRO06SqpMeqbMOqNkiWr+oZZNIQLb A==; X-CSE-ConnectionGUID: HhWRVrkfR02ccO3Vslz0KA== X-CSE-MsgGUID: y8autz/1Taqi6lWMaShsyQ== X-IronPort-AV: E=McAfee;i="6800,10657,11685"; a="70774998" X-IronPort-AV: E=Sophos;i="6.21,258,1763452800"; d="scan'208";a="70774998" Received: from orviesa004.jf.intel.com ([10.64.159.144]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2026 15:54:40 -0800 X-CSE-ConnectionGUID: sG4t/9zyQ9SSLWRMcMXrIw== X-CSE-MsgGUID: MSApCQ3MSUmS7ixGrnbxNQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,258,1763452800"; d="scan'208";a="212951292" Received: from kcaccard-desk.amr.corp.intel.com (HELO [10.125.109.190]) ([10.125.109.190]) by orviesa004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jan 2026 15:54:39 -0800 Message-ID: Date: Wed, 28 Jan 2026 15:54:38 -0800 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 08/26] x86/virt/seamldr: Retrieve P-SEAMLDR information To: Chao Gao , linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org Cc: reinette.chatre@intel.com, ira.weiny@intel.com, kai.huang@intel.com, dan.j.williams@intel.com, yilun.xu@linux.intel.com, sagis@google.com, vannapurve@google.com, paulmck@kernel.org, nik.borisov@suse.com, zhenzhong.duan@intel.com, seanjc@google.com, rick.p.edgecombe@intel.com, kas@kernel.org, dave.hansen@linux.intel.com, vishal.l.verma@intel.com, Farrah Chen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" References: <20260123145645.90444-1-chao.gao@intel.com> <20260123145645.90444-9-chao.gao@intel.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzUVEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gKEludGVsIFdvcmsgQWRkcmVzcykgPGRhdmUuaGFuc2VuQGludGVs LmNvbT7CwXgEEwECACIFAlQ+9J0CGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEGg1 lTBwyZKwLZUP/0dnbhDc229u2u6WtK1s1cSd9WsflGXGagkR6liJ4um3XCfYWDHvIdkHYC1t MNcVHFBwmQkawxsYvgO8kXT3SaFZe4ISfB4K4CL2qp4JO+nJdlFUbZI7cz/Td9z8nHjMcWYF IQuTsWOLs/LBMTs+ANumibtw6UkiGVD3dfHJAOPNApjVr+M0P/lVmTeP8w0uVcd2syiaU5jB aht9CYATn+ytFGWZnBEEQFnqcibIaOrmoBLu2b3fKJEd8Jp7NHDSIdrvrMjYynmc6sZKUqH2 I1qOevaa8jUg7wlLJAWGfIqnu85kkqrVOkbNbk4TPub7VOqA6qG5GCNEIv6ZY7HLYd/vAkVY E8Plzq/NwLAuOWxvGrOl7OPuwVeR4hBDfcrNb990MFPpjGgACzAZyjdmYoMu8j3/MAEW4P0z F5+EYJAOZ+z212y1pchNNauehORXgjrNKsZwxwKpPY9qb84E3O9KYpwfATsqOoQ6tTgr+1BR CCwP712H+E9U5HJ0iibN/CDZFVPL1bRerHziuwuQuvE0qWg0+0SChFe9oq0KAwEkVs6ZDMB2 P16MieEEQ6StQRlvy2YBv80L1TMl3T90Bo1UUn6ARXEpcbFE0/aORH/jEXcRteb+vuik5UGY 5TsyLYdPur3TXm7XDBdmmyQVJjnJKYK9AQxj95KlXLVO38lczsFNBFRjzmoBEACyAxbvUEhd GDGNg0JhDdezyTdN8C9BFsdxyTLnSH31NRiyp1QtuxvcqGZjb2trDVuCbIzRrgMZLVgo3upr MIOx1CXEgmn23Zhh0EpdVHM8IKx9Z7V0r+rrpRWFE8/wQZngKYVi49PGoZj50ZEifEJ5qn/H Nsp2+Y+bTUjDdgWMATg9DiFMyv8fvoqgNsNyrrZTnSgoLzdxr89FGHZCoSoAK8gfgFHuO54B lI8QOfPDG9WDPJ66HCodjTlBEr/Cwq6GruxS5i2Y33YVqxvFvDa1tUtl+iJ2SWKS9kCai2DR 3BwVONJEYSDQaven/EHMlY1q8Vln3lGPsS11vSUK3QcNJjmrgYxH5KsVsf6PNRj9mp8Z1kIG qjRx08+nnyStWC0gZH6NrYyS9rpqH3j+hA2WcI7De51L4Rv9pFwzp161mvtc6eC/GxaiUGuH BNAVP0PY0fqvIC68p3rLIAW3f97uv4ce2RSQ7LbsPsimOeCo/5vgS6YQsj83E+AipPr09Caj 0hloj+hFoqiticNpmsxdWKoOsV0PftcQvBCCYuhKbZV9s5hjt9qn8CE86A5g5KqDf83Fxqm/ vXKgHNFHE5zgXGZnrmaf6resQzbvJHO0Fb0CcIohzrpPaL3YepcLDoCCgElGMGQjdCcSQ+Ci FCRl0Bvyj1YZUql+ZkptgGjikQARAQABwsFfBBgBAgAJBQJUY85qAhsMAAoJEGg1lTBwyZKw l4IQAIKHs/9po4spZDFyfDjunimEhVHqlUt7ggR1Hsl/tkvTSze8pI1P6dGp2XW6AnH1iayn yRcoyT0ZJ+Zmm4xAH1zqKjWplzqdb/dO28qk0bPso8+1oPO8oDhLm1+tY+cOvufXkBTm+whm +AyNTjaCRt6aSMnA/QHVGSJ8grrTJCoACVNhnXg/R0g90g8iV8Q+IBZyDkG0tBThaDdw1B2l asInUTeb9EiVfL/Zjdg5VWiF9LL7iS+9hTeVdR09vThQ/DhVbCNxVk+DtyBHsjOKifrVsYep WpRGBIAu3bK8eXtyvrw1igWTNs2wazJ71+0z2jMzbclKAyRHKU9JdN6Hkkgr2nPb561yjcB8 sIq1pFXKyO+nKy6SZYxOvHxCcjk2fkw6UmPU6/j/nQlj2lfOAgNVKuDLothIxzi8pndB8Jju KktE5HJqUUMXePkAYIxEQ0mMc8Po7tuXdejgPMwgP7x65xtfEqI0RuzbUioFltsp1jUaRwQZ MTsCeQDdjpgHsj+P2ZDeEKCbma4m6Ez/YWs4+zDm1X8uZDkZcfQlD9NldbKDJEXLIjYWo1PH hYepSffIWPyvBMBTW2W5FRjJ4vLRrJSUoEfJuPQ3vW9Y73foyo/qFoURHO48AinGPZ7PC7TF vUaNOTjKedrqHkaOcqB185ahG2had0xnFsDPlx5y In-Reply-To: <20260123145645.90444-9-chao.gao@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/23/26 06:55, Chao Gao wrote: > P-SEAMLDR returns its information e.g., version and supported features, in > response to the SEAMLDR.INFO SEAMCALL. > > This information is useful for userspace. For example, the admin can decide > which TDX module versions are compatible with the P-SEAMLDR according to > the P-SEAMLDR version. > > Add and export seamldr_get_info() which retrieves P-SEAMLDR information by I don't need to know what the function name is. That's in the code. > invoking SEAMLDR.INFO SEAMCALL in preparation for exposing P-SEAMLDR > version and other necessary information to userspace. I also want to know what spec you are getting this out of. I think it's also worth calling out that there are SEAMLDR calls for both: SEAMLDR_INFO and SEAMLDR_SEAMINFO Which is astonishingly confusing. Please have mercy on folks that are looking through the docs for the first time and explain this. > diff --git a/arch/x86/include/asm/seamldr.h b/arch/x86/include/asm/seamldr.h > new file mode 100644 > index 000000000000..d1e9f6e16e8d > --- /dev/null > +++ b/arch/x86/include/asm/seamldr.h > @@ -0,0 +1,27 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef _ASM_X86_SEAMLDR_H > +#define _ASM_X86_SEAMLDR_H > + > +#include > + > +struct seamldr_info { /* * This called the "SEAMLDR_INFO" data structure and is defined * in "SEAM Loader (SEAMLDR) Interface Specification". */ > + u32 version; > + u32 attributes; > + u32 vendor_id; > + u32 build_date; > + u16 build_num; > + u16 minor_version; > + u16 major_version; > + u16 update_version; > + u8 reserved0[4]; Why not label this: u32 acm_x2apicid: /* unused by kernel */ ? > + u32 num_remaining_updates; > + u8 reserved1[224]; > +} __packed; > + > +#ifdef CONFIG_INTEL_TDX_MODULE_UPDATE > +const struct seamldr_info *seamldr_get_info(void); > +#else > +static inline const struct seamldr_info *seamldr_get_info(void) { return NULL; } > +#endif > + > +#endif > diff --git a/arch/x86/virt/vmx/tdx/seamldr.c b/arch/x86/virt/vmx/tdx/seamldr.c > index b99d73f7bb08..6a83ae405fac 100644 > --- a/arch/x86/virt/vmx/tdx/seamldr.c > +++ b/arch/x86/virt/vmx/tdx/seamldr.c > @@ -9,9 +9,16 @@ > #include > #include > > +#include > + > #include "seamcall.h" > > -static __maybe_unused int seamldr_call(u64 fn, struct tdx_module_args *args) > +/* P-SEAMLDR SEAMCALL leaf function */ > +#define P_SEAMLDR_INFO 0x8000000000000000 /* * The SEAMLDR.INFO documentation requires * this to be aligned to a 256-byte boundary. */ > +static struct seamldr_info seamldr_info __aligned(256); > + > +static inline int seamldr_call(u64 fn, struct tdx_module_args *args) > { > unsigned long flags; > u64 vmcs; > @@ -54,3 +61,11 @@ static __maybe_unused int seamldr_call(u64 fn, struct tdx_module_args *args) > WARN_ONCE(1, "Failed to save/restore the current VMCS"); > return -EIO; > } > + > +const struct seamldr_info *seamldr_get_info(void) > +{ > + struct tdx_module_args args = { .rcx = __pa(&seamldr_info) }; > + > + return seamldr_call(P_SEAMLDR_INFO, &args) ? NULL : &seamldr_info; > +} > +EXPORT_SYMBOL_FOR_MODULES(seamldr_get_info, "tdx-host"); I'd also prefer a BUILD_BUG_ON(sizeof(struct seamldr_info) != 2048); just as a sanity check. It doesn't cost anything and it makes sure that as you muck around with reserved fields and padding that there's at least one check making sure it's OK.