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X-IronPort-AV: E=McAfee;i="6600,9927,10746"; a="362277235" X-IronPort-AV: E=Sophos;i="6.00,255,1681196400"; d="scan'208";a="362277235" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jun 2023 18:06:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10746"; a="858376029" X-IronPort-AV: E=Sophos;i="6.00,255,1681196400"; d="scan'208";a="858376029" Received: from alaird-mobl2.amr.corp.intel.com (HELO [10.212.177.39]) ([10.212.177.39]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Jun 2023 18:06:30 -0700 Message-ID: <4069285d-1653-4cbf-a3b3-24727697754b@intel.com> Date: Mon, 19 Jun 2023 18:06:30 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH v11 18/20] x86: Handle TDX erratum to reset TDX private memory during kexec() and reboot Content-Language: en-US To: "Huang, Kai" , "kirill.shutemov@linux.intel.com" Cc: "kvm@vger.kernel.org" , "Luck, Tony" , "david@redhat.com" , "bagasdotme@gmail.com" , "ak@linux.intel.com" , "Wysocki, Rafael J" , "linux-kernel@vger.kernel.org" , "Chatre, Reinette" , "Christopherson,, Sean" , "pbonzini@redhat.com" , "tglx@linutronix.de" , "linux-mm@kvack.org" , "Yamahata, Isaku" , "Shahar, Sagi" , "peterz@infradead.org" , "imammedo@redhat.com" , "Gao, Chao" , "Brown, Len" , "sathyanarayanan.kuppuswamy@linux.intel.com" , "Huang, Ying" , "Williams, Dan J" References: <5aa7506d4fedbf625e3fe8ceeb88af3be1ce97ea.1685887183.git.kai.huang@intel.com> <20230609132301.uvvp27yr5kpenl6f@box.shutemov.name> <58f34b4b81b6d6b37d3386dec0f073e6eb7a97ff.camel@intel.com> <20230612075830.jbrdd6ysz4qq7wdf@box.shutemov.name> <4c7effc3abe71aa1cbee41f3bd46b97aed40be26.camel@intel.com> <48d5a29a-878c-665d-6ac2-6f0563bf6f3c@intel.com> <5782c8c2bb3e76a802e4a81c553a21edbaee7c47.camel@intel.com> <20230619144651.kvmscndienyfr3my@box.shutemov.name> <63477d22-26ef-dd08-a3b0-93931b7d1d16@intel.com> <0be5634f390015ee6badb3f2b2154ad90eb70434.camel@intel.com> From: Dave Hansen In-Reply-To: <0be5634f390015ee6badb3f2b2154ad90eb70434.camel@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 53A8E16001B X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: 63i3nu757wxgxiyg7br3dfnjjc8go6em X-HE-Tag: 1687223193-861322 X-HE-Meta: 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 h+PNQmMm RH3eNkMsGUgWdRmLnEanr4761M55kvFIRcpcZ6D1yFTNEXToPwOOdOrjR4mRIU1gZbOd/RAX0lYdah89ZSKg8n0cmE7fpRyvVkvOeEOAKlbRE55V5M8yYlTDkenSSPqEGq8dc2L2i25e2uZr/vPDyf8n+3z1mp0d9a/SW76lIYabVeE0vHOdP2DyFvYncuBUa3pWJ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 6/19/23 17:56, Huang, Kai wrote: > Any comments to below? Nothing that I haven't already said in this thread: > Just use a normal old atomic_t or set_bit()/test_bit(). They have > built-in memory barriers are are less likely to get botched. I kinda made a point of literally suggesting "atomic_t or set_bit()/test_bit()". I even told you why: "built-in memory barriers". Guess what READ/WRITE_ONCE() *don't* have. Memory barriers.