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X-CSE-ConnectionGUID: NxbUgUTbSEGtgvWBhm45cQ== X-CSE-MsgGUID: JPCsV7C4THCIe70hycz44A== X-IronPort-AV: E=McAfee;i="6800,10657,11697"; a="71796612" X-IronPort-AV: E=Sophos;i="6.21,283,1763452800"; d="scan'208";a="71796612" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Feb 2026 14:19:14 -0800 X-CSE-ConnectionGUID: uad6dQ42T/GX63q9Se1gtw== X-CSE-MsgGUID: LtYRWZYJTV+ueNGWx3TBFA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,283,1763452800"; d="scan'208";a="216559668" Received: from unknown (HELO [10.24.81.14]) ([10.24.81.14]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Feb 2026 14:19:14 -0800 Message-ID: <4fe6121b-6fe3-4c97-b796-806533ed6806@intel.com> Date: Tue, 10 Feb 2026 14:19:13 -0800 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: [RFC PATCH v5 16/45] x86/virt/tdx: Add tdx_alloc/free_control_page() helpers To: "Edgecombe, Rick P" , "seanjc@google.com" , "x86@kernel.org" , "dave.hansen@linux.intel.com" , "kas@kernel.org" , "bp@alien8.de" , "mingo@redhat.com" , "tglx@kernel.org" , "pbonzini@redhat.com" Cc: "Huang, Kai" , "ackerleytng@google.com" , "sagis@google.com" , "Annapurve, Vishal" , "linux-kernel@vger.kernel.org" , "Zhao, Yan Y" , "Li, Xiaoyao" , "kvm@vger.kernel.org" , "linux-coco@lists.linux.dev" , "Yamahata, Isaku" , "binbin.wu@linux.intel.com" References: <20260129011517.3545883-1-seanjc@google.com> <20260129011517.3545883-17-seanjc@google.com> <655724f8-0098-40ee-a097-ce4c0249933d@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 2/10/26 14:15, Edgecombe, Rick P wrote: > I'm wasn't familiar with atomic_dec_and_lock(). I'm guess the atomic > part doesn't cover both decrementing *and* taking the lock? Right. Only 1=>0 is under the lock. All other decs are outside the lock. It doesn't do the atomic and the lock "atomically together" somehow.