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[2003:cb:c739:d200:8745:c520:8bf6:b587]) by smtp.gmail.com with ESMTPSA id f14-20020adfe90e000000b003111a9a8dbfsm1924320wrm.44.2023.06.20.05.39.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 20 Jun 2023 05:39:41 -0700 (PDT) Message-ID: <8ea65567-ec8a-3361-e78c-c51a1d8aad47@redhat.com> Date: Tue, 20 Jun 2023 14:39:39 +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 05/20] x86/virt/tdx: Add SEAMCALL infrastructure To: "kirill.shutemov@linux.intel.com" , "Huang, Kai" Cc: "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Hansen, Dave" , "Luck, Tony" , "bagasdotme@gmail.com" , "ak@linux.intel.com" , "Wysocki, Rafael J" , "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: <759e3af5-6aec-7e50-c432-c5e0a0c3cf36@redhat.com> <8e7d6b83347688bb013d7ebb660d0a74a1949d52.camel@intel.com> <20230620122012.mnlgko443qrpfrzg@box.shutemov.name> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20230620122012.mnlgko443qrpfrzg@box.shutemov.name> 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-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 51AE24001B X-Stat-Signature: dbzzq6z7y8ewdgd14gzjhzcuikqutha5 X-Rspam-User: X-HE-Tag: 1687264785-164679 X-HE-Meta: U2FsdGVkX19oY5r0Hcpx80Vo+FsbQunhRvOxdfAKfBbjaFk0lMSOdirx9vqVMTJzp/TIcKZx+tQW5DlRwM8zmy70vqfrCE++CLWgDf9NUs6r/JzmF1bdM8fSWG3oxlteceSkKNvFbZBRVzHrlLzbiq83DEV/kP+JouZ1guydmFAK741ooobagqA0mq44JCVue8tYTvw+XndNAkdEucl5RttD+ky6dNH+uECC6UV66PDd/nifF7NVsKI4W2HEKd89YK2BTb/ABA/V+dGgGLp9VD0Q0TLGSqYqG7W08KnQ5+PA0MyutLaxVp4Y90tsWFYjOVGp9fC5CTW3klPcN2FPR4Zu/swFg+G+WpULoBxcasPHsUONCJYyN6briSZFfqCKFDX6VoIrMQjVAuhp2QyOkyi3Jnr43hP/g0LmOSGk8/57o7Iua4u11atb3cAjAJZ7bvnEe1mlU1+uRReEQ2u7ADXC6vZTHGvf3e1hF4umHZKIuIq5KS8P+ns8QUNFcWNclCqmm+llcjlYDHwdL0u+Qp0fGJCQv673sa0RWpaZ11kcAqpz3rz0VQ+BXOgIz6R6e/1AW0hLxexTQGyWoj4N3Ze4MOIQsBAQi4TTarvxshMEWxV5I7Br3UFn6L662CmW+ZzsWpRC5TdV7pgOc8dZz+w4Ox72WDHgbeHHgj49ra6iXL1r4vJbtyORVsWTfAMrjvFDGgF24lnZdT+ii0ivOTAY7Ub0v9bNIYMrsTDhk5pJ1DL0VT2SCwsSEkUiIsuaj8cSUPGp4Nrguiu1nfvWA4gwfG9pCP9qSZiBOZnXPvPZ+5ciENZyK+h5jR27EgXIP6W/B2vJdHaEuJepWgAmh1iIzg01G/MjSfNCUz9v71y9Kf5ovYSbr+jIZWymZAJrRjsTPMR2KpLqWZrR1iM8tgpiPADQ5WR2+l77ZWr79yj5EPyvb2+5plTH6oZyimwcsyip5qaR+z3gktxNhcB ci0ewUBc DtNM3PPyYVFH462nI05uGoUg3fJO2TsE5Gci5554TwEnxnnrw4UG72Gxl0I/AU461oydWCYO+nLz/84mrdFIc/Fv9GPRvdu/YdaixCXapV2kaRVAQEcvt3ADiD1RhVSCzSm6v3gnNNBJaehNoL6jXcJ/570ifDFhIAzwRR6ZcpZ3T6lB7iVijEZromYeOiuEPrlcfq9rtbxCGqfGels+QL7TK9qUUilMKiRHaAebh27g8Nl8wLBC7s3tMOXpu7rGB8yrp3a/0o6oqBWOxj8vsFbYKimAwU0WEFn70kgpSDxUyY0z9Nu+txmF1pquvqn0DefZ0Y9fk1UbSz/a77quq0MaxCq9+kji+huJhhVSZg2674d4RJJxVYUPgKSLvjqFQKtlTB1b7fiJDCP2dXT2r9rXLhYJOat4of2tILCuZVAZuHI3VBSrlQXxIgTZOAsaWASaq 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 14:20, kirill.shutemov@linux.intel.com wrote: > On Tue, Jun 20, 2023 at 10:37:16AM +0000, Huang, Kai wrote: >>>> + /* >>>> + * SEAMCALL caused #GP or #UD. By reaching here %eax contains >>>> + * the trap number. Convert the trap number to the TDX error >>>> + * code by setting TDX_SW_ERROR to the high 32-bits of %rax. >>>> + * >>>> + * Note cannot OR TDX_SW_ERROR directly to %rax as OR instruction >>>> + * only accepts 32-bit immediate at most. >>> >>> Not sure if that comment is really helpful here. It's a common pattern >>> for large immediates, no? >> >> I am not sure. I guess I am not expert of x86 assembly but only casual writer. >> >> Hi Dave, Kirill, >> >> Are you OK to remove it? > > I would rather keep it. I wanted to ask why separate MOV is needed here, > before I read the comment. Also size of $TDX_SW_ERROR is not visible here, > so it contributes to possible confusion without the comment. > Fine with me, but I'd assume that the assembler will simply complain in case we'd try to use a large immediate. -- Cheers, David / dhildenb