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[2003:cb:c739:d200:8745:c520:8bf6:b587]) by smtp.gmail.com with ESMTPSA id p19-20020a05600c469300b003f7f475c3bcsm22876375wmo.1.2023.06.20.04.14.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 20 Jun 2023 04:14:37 -0700 (PDT) Message-ID: <193d0e6d-27b6-b50e-8a3e-35c1816b20fc@redhat.com> Date: Tue, 20 Jun 2023 13:14:36 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v11 06/20] x86/virt/tdx: Handle SEAMCALL running out of entropy error To: "Huang, Kai" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Cc: "Hansen, Dave" , "Luck, Tony" , "bagasdotme@gmail.com" , "ak@linux.intel.com" , "Wysocki, Rafael J" , "kirill.shutemov@linux.intel.com" , "Christopherson,, Sean" , "Chatre, Reinette" , "pbonzini@redhat.com" , "tglx@linutronix.de" , "linux-mm@kvack.org" , "Yamahata, Isaku" , "peterz@infradead.org" , "Shahar, Sagi" , "imammedo@redhat.com" , "Gao, Chao" , "Brown, Len" , "sathyanarayanan.kuppuswamy@linux.intel.com" , "Huang, Ying" , "Williams, Dan J" References: <9b3582c9f3a81ae68b32d9997fcd20baecb63b9b.1685887183.git.kai.huang@intel.com> <1cc1879691fcd077fed1a485de799594d751a8ec.camel@intel.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <1cc1879691fcd077fed1a485de799594d751a8ec.camel@intel.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: twcrsqeeibf4zomhz1tddpcpu7nmxfti X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: CB316180020 X-Rspam-User: X-HE-Tag: 1687259683-724172 X-HE-Meta: U2FsdGVkX1/Z2iwiEw+yb8s/3YYbj/LkNINNoyhA0mv3gYQXvjJ3rFXA7sXFkS4eq1DM5t55g01mD+T++noYyo4rKT5g/y0bHNgR3/8PcDCdI1FNxKRKyN3LzHaPd2JlGoCUqD2mpuHFPp8OOrzzm4Olw9YhDVtRB2zW5ulSeb2tk3boR6+boJmyqadigOE7fwxajrRhNfV2SDHno14/y3S6O+k/+gfDZMOHbrVoA6zbFtt9YDN6tZ+ASyzAm+UBciMQ0zydMELuMqlos8xkwBKWa7yNhtxBBu27zm0oBRS1dZ3AdLXbqa10tEGvJtuCWXjuOb0oHG7cJhtIKzB4J3IGzDDTtGZRaj5cWWTDn161f3DH2todmTFGaAIzh8zeYdW713DnXM5cFlbY5C9n0uZ700RSxCDh7dKLa7vg7+VmMZBKB0WM2Fr4tDp2KJMRRoITUCA+eHgbp2nu7EPs4hTEdRwiW2vvt943AIPdSn9oSuK+1VEbpD+VaNGjPiz8uenED8GtPMPK+TYHWvNkSKw0bttOIVT3Gprl5thywGv2mZm7Pl/W8/u+c0wgGljCfzCbymH5WelH2mnqNs/Q59mutKRLzWzPZ25k+ACtd3tac4OX14XQywTnmocBkaQ5M3/P4T3mrI/0mD52FAthet6jIm+DbOtjqp3fbiTF9dBKOgBfTJgniLRnH6yNOgfQtWnCzdFlX6m1MZY1f4yMhNduiipA+XMxI5XYnYR9wfObZl2Wvvm44MZJawHwCuAO2zo0uqCQ448dSw0WnvPJehD+rQSTCl9/FnwdxaWx6I8smwwd3DE5wHaUmbhqxN0qJVJyQe/w7on8o3/+byaUl0RwnXTprlPLU+DIWy6debHqK1Dg7Fju89lMY5ZP3Ezc3eyL9zcfuoMvTLzuLOE419EAuiVoU2arRoJmg/D9v0h2QB3HTglKA7g2IG7vdWZJESvZSIiCXi0qR4lebS4 MsXIbweq 7UBVUgyofB4NGveZ3DvabQ0X9lyQ1Wh7rnLIczIWdLYIFL+hY08BhKDOv6caVSopfXVRry6kQSS1n/0oLEhLdNTJPag5GOTpjTZEkhkeMjk4m1qk1rp+Ux0aAJfg7g58VN+f69SUxB6iZgdFUuroBcmgE026SaF+E4O2pReosTU7vgnJNhmKtOgS++vNWtjZ5sFqElwEQ8CSDWAl/7ACVjf0fv4E+fHoFn0VhZXlGwUXireSmcBtyUUM5AqHHkXhMuDQChbRk2Awe87q8dL5r4kWe7TRUxHjnQWkWw4cpOTmAeddcUk8xHFXYajM6RknVwk6+fSpG2PLQDSPQ/MpFvKcfOB2OK4xkHfEcyDTKW2xANUJ1SNZqAqJepGFBx8TnkN2VI9WFQi1v245/k83T89cCZ0et0j1lE+BoOEWKpU6lstE= 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 20.06.23 12:39, Huang, Kai wrote: > >>> @@ -33,12 +34,24 @@ static int __always_unused seamcall(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, >>> struct tdx_module_output *out) >>> { >>> int cpu, ret = 0; >>> + int retry; >>> u64 sret; >>> >>> /* Need a stable CPU id for printing error message */ >>> cpu = get_cpu(); >>> >>> - sret = __seamcall(fn, rcx, rdx, r8, r9, out); >>> + /* >>> + * Certain SEAMCALL leaf functions may return error due to >>> + * running out of entropy, in which case the SEAMCALL should >>> + * be retried. Handle this in SEAMCALL common function. >>> + * >>> + * Mimic the existing rdrand_long() to retry >>> + * RDRAND_RETRY_LOOPS times. >>> + */ >>> + retry = RDRAND_RETRY_LOOPS; >> >> Nit: I'd just do a "int retry = RDRAND_RETRY_LOOPS" and simplify this >> comment to "Mimic rdrand_long() retry behavior." > > OK will do. > > But I think you are talking about replacing the second paragraph but not the > entire comment? > Yes. -- Cheers, David / dhildenb