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AJvYcCULdJKrt8Nhq4B+t2VzncJNHQ9tXCN0nx//FK+w9S+m+Z6mqdjhmAF1dNTXCYlaoskDyHoEekCZQgbMBTClfY/WjVjT X-Gm-Message-State: AOJu0YyGFRxsz9ihvQ3uh26XmhQ8U1WQnJGqaDU4amQTwZ5Pu5IYM4kM XLR0jBvSgQKgZ4m9gwiEwHmUULR7zZOH+zA3Ysf90RCp1V0xtVmuxCu/jIT88Q0OQ22PtYfzifB Mtg== X-Google-Smtp-Source: AGHT+IExCGrJPdAW2GeOLG491SIcrLlhsuV3XsGg9Om6QoQqLDgMtfFqtvcSt+vrYfYHgj0J9CVY23pc2dY= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a65:434d:0:b0:5d8:bb9d:4fd0 with SMTP id k13-20020a65434d000000b005d8bb9d4fd0mr2015pgq.4.1712180203127; Wed, 03 Apr 2024 14:36:43 -0700 (PDT) Date: Wed, 3 Apr 2024 14:36:41 -0700 In-Reply-To: <70d7a20a-72dc-4ded-a35f-684de44eb6e6@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <8f64043a6c393c017347bf8954d92b84b58603ec.1708933498.git.isaku.yamahata@intel.com> <54ae3bbb-34dc-4b10-a14e-2af9e9240ef1@intel.com> <8d79db2af4e0629ad5dea6d8276fc5cda86a890a.camel@intel.com> <70d7a20a-72dc-4ded-a35f-684de44eb6e6@intel.com> Message-ID: Subject: Re: [PATCH v19 007/130] x86/virt/tdx: Export SEAMCALL functions From: Sean Christopherson To: Dave Hansen Cc: Kai Huang , Tina Zhang , Rick P Edgecombe , Hang Yuan , "x86@kernel.org" , Bo2 Chen , "sagis@google.com" , "linux-kernel@vger.kernel.org" , "isaku.yamahata@gmail.com" , Erdem Aktas , "kvm@vger.kernel.org" , "pbonzini@redhat.com" , Isaku Yamahata Content-Type: text/plain; charset="us-ascii" On Wed, Mar 20, 2024, Dave Hansen wrote: > On 3/20/24 05:09, Huang, Kai wrote: > > I can try to do if you guys believe this should be done, and should be done > > earlier than later, but I am not sure _ANY_ optimization around SEAMCALL will > > have meaningful performance improvement. > > I don't think Sean had performance concerns. > > I think he was having a justifiably violent reaction to how much more > complicated the generated code is to do a SEAMCALL versus a good ol' KVM > hypercall. Yep. The code essentially violates the principle of least surprise. I genuinely thought I was dumping the wrong function(s) when I first looked at the output.