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X-CSE-ConnectionGUID: ZJMuvWbDSNyC9P/QB0fTmw== X-CSE-MsgGUID: 1rbQYLVbRFqb6Qqxx86uwA== X-IronPort-AV: E=McAfee;i="6800,10657,11475"; a="53380637" X-IronPort-AV: E=Sophos;i="6.16,267,1744095600"; d="scan'208";a="53380637" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jun 2025 07:46:56 -0700 X-CSE-ConnectionGUID: 8+rRqYoXR/yClCRd1+gTtQ== X-CSE-MsgGUID: DzhWelVySNmH0eJh8vyXAw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,267,1744095600"; d="scan'208";a="151959823" Received: from spandruv-desk1.amr.corp.intel.com (HELO [10.125.109.24]) ([10.125.109.24]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jun 2025 07:46:57 -0700 Message-ID: <3e55fd58-1d1c-437a-9e0a-72ac92facbb5@intel.com> Date: Thu, 26 Jun 2025 07:46:55 -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: [PATCHv2 01/12] x86/tdx: Consolidate TDX error handling To: "kirill.shutemov@linux.intel.com" , Sean Christopherson Cc: Rick P Edgecombe , "pbonzini@redhat.com" , "dave.hansen@linux.intel.com" , Chao Gao , "bp@alien8.de" , Kai Huang , "x86@kernel.org" , "mingo@redhat.com" , Yan Y Zhao , "tglx@linutronix.de" , "kvm@vger.kernel.org" , "linux-coco@lists.linux.dev" , Isaku Yamahata , "linux-kernel@vger.kernel.org" References: <20250609191340.2051741-1-kirill.shutemov@linux.intel.com> <20250609191340.2051741-2-kirill.shutemov@linux.intel.com> <5cfb2e09-7ecb-4144-9122-c11152b18b5e@intel.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/26/25 02:25, kirill.shutemov@linux.intel.com wrote: >> Can we turn them into macros that make it super obvious they are checking if the >> error code *is* xyz? E.g. >> >> #define IS_TDX_ERR_OPERAND_BUSY >> #define IS_TDX_ERR_OPERAND_INVALID >> #define IS_TDX_ERR_NO_ENTROPY >> #define IS_TDX_ERR_SW_ERROR >>>> As is, it's not at all clear that things like tdx_success() are >> simply checks, as opposed to commands. > I remember Dave explicitly asked for inline functions over macros > where possible. > > Can we keep them as functions, but give the naming scheme you > proposing (but lowercase)? Macros versus function isn't super important. I think Sean was asking if we could do: if (err == IS_TDX_ERR_OPERAND_BUSY) ... instead of: if (tdx_operand_busy(err)) ... We can do that, bu we first need to know that the whole bottom of the return code register is empty. Unfortunately, a quick grep of the TDX module source shows a bunch of these: > return_val = api_error_with_operand_id(TDX_OPERAND_BUSY, OPERAND_ID_MIGSC); I'll refrain from casting judgement on why the TDX module needs such fancy, fine-grained error codes and our little hobby kernel over here mostly gets by on a couple errno's ... but I digress. Those fancy pants error codes are why we need: static inline u64 tdx_status(u64 err) { return err & TDX_STATUS_MASK; } and can't just check the err directly. We need to mask out the fancy pants bits first. To get to what Sean is asking for, we'd have to do the tdx_status() masking in the low-level SEAMCALL helpers and have them all return a masked error code. Or maybe just bite the bullet and mostly move over to errno's. That wouldn't be horrible. For errno's or a masked TDX-format err, callers could always go digging in tdx_module_args if they need the bits that got masked out. But it would take some work.