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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 Content-Language: en-US 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> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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