From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.19]) (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 8B3D53469F6; Wed, 20 May 2026 19:35:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779305711; cv=none; b=ni+kYSpUXeGHKYpFr1RJ3OhPpo6WeI84OIRDEckd4PqoWCEDuuD8aI5hY7e6SrvdS1sgAaB3HDUP2mP74WtWVVfg0VeoQScvsWZ1AO57xKQdZgiFlsFr5X5tw9xRImWaG4hEweylC9FDgLOn7kbpiY2zjCNZE4o1O8jEE41ZAok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779305711; c=relaxed/simple; bh=RdcZ8ZY+8Tul4HDDN6hC6F7eMjzVrJ13hT5KbVvvu0o=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=l4KnoEdyfYXlYya2FpFMtUB2GK+kDG0E8pw7dfgJ8k8kT571Ne32VknOy++qDA548KXJNT3JSbwfTLa0uTmR8U+JjegsHcYEKCEv/MTkcLhap0nQnQ1jxe3maNziBNRWGZWtRVT1m6fw42lZ9+BW3Zj/mNO6wzfIJji/bGePCMk= 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=ZFmyN6mn; arc=none smtp.client-ip=198.175.65.19 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="ZFmyN6mn" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1779305710; x=1810841710; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=RdcZ8ZY+8Tul4HDDN6hC6F7eMjzVrJ13hT5KbVvvu0o=; b=ZFmyN6mnrWLnR3kqtz8r05ee5eMM5RfsSid0nU/FvE0j9kNPuMUqnjtt wW47rgNPwiUIDZBJrzWA/aSgFH/ChKIdYSs24wrzyTXzC0ykSNkQKqEAZ R2bYBQt82FI4RBA329tF+5Es4CSML/6mzbMn/RrzYc+7QYdpudaIOkxtr clvxsdfYRfEEsCda8AKjrloxbfYpSmb1NpRip/xSjj+tCm9tWMG56hmzU YroTjV/BKQ1ZXEFybcsrdaUTUlWItOjkOO24IW+hZmqnlNkJuTLI+KYJe 73hDeplZl/KtOrPpEdYcyA4acYYBe0Yy6cjX725xjq/a/iOVi97s9LPbR w==; X-CSE-ConnectionGUID: Qd+rDAmZQe+jQK1qkhLpqQ== X-CSE-MsgGUID: r/tMsR9MTcGJQUsZqWmCGQ== X-IronPort-AV: E=McAfee;i="6800,10657,11792"; a="80182711" X-IronPort-AV: E=Sophos;i="6.23,244,1770624000"; d="scan'208";a="80182711" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2026 12:35:09 -0700 X-CSE-ConnectionGUID: uHBEFyT4T4GuXcowqdFFVA== X-CSE-MsgGUID: 9or94R8nSQm0LbaROot03Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,244,1770624000"; d="scan'208";a="245274820" Received: from spandruv-mobl5.amr.corp.intel.com (HELO [10.125.109.190]) ([10.125.109.190]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 May 2026 12:35:09 -0700 Message-ID: Date: Wed, 20 May 2026 12:35:13 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 22/25] x86/virt/tdx: Reject updates during compatibility-sensitive operations To: Chao Gao , kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org Cc: binbin.wu@linux.intel.com, dave.hansen@linux.intel.com, djbw@kernel.org, ira.weiny@intel.com, kai.huang@intel.com, kas@kernel.org, nik.borisov@suse.com, paulmck@kernel.org, pbonzini@redhat.com, reinette.chatre@intel.com, rick.p.edgecombe@intel.com, sagis@google.com, seanjc@google.com, tony.lindgren@linux.intel.com, vannapurve@google.com, vishal.l.verma@intel.com, yilun.xu@linux.intel.com, xiaoyao.li@intel.com, yan.y.zhao@intel.com, Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" References: <20260520133909.409394-1-chao.gao@intel.com> <20260520133909.409394-23-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: <20260520133909.409394-23-chao.gao@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/20/26 06:38, Chao Gao wrote: > int tdx_module_shutdown(void) > { > struct tdx_sys_info_handoff handoff = {}; > struct tdx_module_args args = {}; > int ret, cpu; > + u64 err; > > ret = get_tdx_sys_info_handoff(&handoff); > WARN_ON_ONCE(ret); > @@ -1288,9 +1291,30 @@ int tdx_module_shutdown(void) > * module can produce and most likely supported by newer modules. > */ > args.rcx = handoff.module_hv; > - ret = seamcall_prerr(TDH_SYS_SHUTDOWN, &args); > - if (ret) > - return ret; > + > + /* > + * This flag tells the TDX module to reject shutdown if it races > + * with a "sensitive" ongoing operation. That eliminates exposure > + * to a TDX erratum which can corrupt TDX guest states. > + * > + * This flag is not supported by all TDX modules and may cause > + * the shutdown (and subsequent update procedure) to fail. > + */ > + args.rcx |= TDX_SYS_SHUTDOWN_AVOID_COMPAT_SENSITIVE; > + > + err = seamcall(TDH_SYS_SHUTDOWN, &args); > + > + /* > + * The shutdown ran into a "sensitive" ongoing operation. Signal > + * to userspace that it can retry. > + */ > + if ((err & TDX_SEAMCALL_STATUS_MASK) == TDX_UPDATE_COMPAT_SENSITIVE) > + return -EBUSY; > + > + if (err) { > + seamcall_err(TDH_SYS_SHUTDOWN, err, &args); > + return -EIO; > + } This function is pretty tidy. More or less: ret = get_tdx_sys_info_handoff(&handoff); if (ret) return args.foo = handoff.bar; ret = seamcall_prerr(TDH_SYS_SHUTDOWN, &args); if (ret) return memset(&tdx_module_state, 0, sizeof(tdx_module_state)); for_each_possible_cpu(cpu) per_cpu(tdx_lp_initialized, cpu) = false; The logic's not bad, right? Get the handoff data, hand it off to something, then go set some fields. Then what does this patch do? It goes and globs a just huge blob of TDH_SYS_SHUTDOWN errata handling and implementation details right smack in the middle. Our tidy little function is no more. I really with this would trigger folks' gag reflexes. It's *SO* easy to fix. It's *so* easy to keep the code tidy and hide the dead bodies so that the logic can still be followed. I'm probably going to drop this for now.