From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (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 72CD31A38EE for ; Tue, 10 Sep 2024 19:54:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725998083; cv=none; b=obG/PcERa9xdwsZCeOVAKPi1BN2Q6j0S8RdRQWBGSWJtYDv6txp8MDff2I8pO9B3RDQQCAeI0NjNMve+/e1F8FJkLgrMXTs94tG/DUar3dJz1I9d9UGn5vyV5a2yr3c+0qnBqiIOSODS6qG+lYjVx7gRcHeSnHKpIlTEeS2yh+U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725998083; c=relaxed/simple; bh=jpKvKU2Xh/kvgsUOqxFMwQUdES/MaS9Mwm4xp7/CYzE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=h5vUgWkXg7SKzp0lrGJB8Jz41GwNxUFnMpstjeQffj7aJBxcjBB24BiXfYmPJ5BEVIUqW8ZH2IDARVk9d/wUYftEN7DOw26pMhaLSOvamG4sz8xmKf2g/M5x1IkE5dwrNLhY8SIYhlVQDb+CN28twnWcBTgQIkFnPb/TP1jAYQg= 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=X4EvO5fH; arc=none smtp.client-ip=192.198.163.12 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="X4EvO5fH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1725998080; x=1757534080; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=jpKvKU2Xh/kvgsUOqxFMwQUdES/MaS9Mwm4xp7/CYzE=; b=X4EvO5fH+c0oiVkS+zatd4PZhZN461hudKKS7FXpg7n1jD/ZkZylMqJA /t0K1ncCxn0E2iw/skqnTGJSiuOsDypNuSLJYcNvJ9XXNI7isb0qvxgyo N9zZO824Eh0lUO8Iii3lMSkqE+aerCsac5SZjiWG1mjNe6o7TgIhm+eQI T2vKVbKpr6p8/3LxCzfqjuLdosRaOjYV6ih6SbOqCmtlsmPjhrBCg9qBi 9PxAo8VWaK0rzUagKDBYSe94RhXlK3aMsqUD8Uszr6GvGuIBb7vdLzjBJ ZOqynNGfLjsZyg9BN91nq+UskMCX5rgqPgjAxZkToTov13jfybFyF04e/ Q==; X-CSE-ConnectionGUID: iu60DvZ7RJOcy3Z41wSEvw== X-CSE-MsgGUID: qn6Z5qUkTjWh8G4hhd5O1w== X-IronPort-AV: E=McAfee;i="6700,10204,11191"; a="28659489" X-IronPort-AV: E=Sophos;i="6.10,218,1719903600"; d="scan'208";a="28659489" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 12:54:39 -0700 X-CSE-ConnectionGUID: qzGg5+0YTauTCOWOGUdDTg== X-CSE-MsgGUID: nvPZHRgdSZ+dcoOWuwvZVQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,218,1719903600"; d="scan'208";a="97825280" Received: from dgramcko-desk.amr.corp.intel.com (HELO [10.124.223.101]) ([10.124.223.101]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Sep 2024 12:54:39 -0700 Message-ID: <24ec1497-af03-4e65-abb4-db89590fb28e@intel.com> Date: Tue, 10 Sep 2024 12:54:19 -0700 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 1/6] x86/tdx: Fix "in-kernel MMIO" check To: Alexey Gladkov , linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , "Kirill A. Shutemov" , Andrew Morton , Yuan Yao , Geert Uytterhoeven , Yuntao Wang , Kai Huang , Baoquan He , Oleg Nesterov , cho@microsoft.com, decui@microsoft.com, John.Starks@microsoft.com, stable@vger.kernel.org References: <398de747c81e06be4d3f3602ee11a7e2881f31ed.1725622408.git.legion@kernel.org> 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: <398de747c81e06be4d3f3602ee11a7e2881f31ed.1725622408.git.legion@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/6/24 04:49, Alexey Gladkov wrote: > +static inline bool is_kernel_addr(unsigned long addr) > +{ > + return (long)addr < 0; > +} > + > static int handle_mmio(struct pt_regs *regs, struct ve_info *ve) > { > unsigned long *reg, val, vaddr; > @@ -434,6 +439,11 @@ static int handle_mmio(struct pt_regs *regs, struct ve_info *ve) > return -EINVAL; > } > > + if (!user_mode(regs) && !is_kernel_addr(ve->gla)) { > + WARN_ONCE(1, "Access to userspace address is not supported"); > + return -EINVAL; > + } Should we really be open-coding a "is_kernel_addr" check? I mean, TASK_SIZE_MAX is there for a reason. While I doubt we'd ever change the positive vs. negative address space convention on 64-bit, I don't see a good reason to write a 64-bit x86-specific is_kernel_addr() when a more generic, portable and conventional idiom would do. So, please use either a: addr < TASK_SIZE_MAX check, or use fault_in_kernel_space() directly.