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b=NcQX6wJ1j3744KGLOzs5UpIxmu0ayz7XOden3QuCrMVOseViESrvulijZnj2cO7kWysFhPMb6gjmm21WHkGEc8V5+EOCoTzR3X0jV6fgZyVZswCeyH1M7lZbBEtTfMIRmfsCinjBprenK7IghouwewzJORyqD+bRs4hs9FmUjqQ= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BL3PR12MB9049.namprd12.prod.outlook.com (2603:10b6:208:3b8::21) by BL1PR12MB5923.namprd12.prod.outlook.com (2603:10b6:208:39a::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9654.19; Mon, 2 Mar 2026 23:12:00 +0000 Received: from BL3PR12MB9049.namprd12.prod.outlook.com ([fe80::ae6a:9bdd:af5b:e9ad]) by BL3PR12MB9049.namprd12.prod.outlook.com ([fe80::ae6a:9bdd:af5b:e9ad%5]) with mapi id 15.20.9654.022; Mon, 2 Mar 2026 23:12:00 +0000 Message-ID: <6c2b6e6c-f321-436c-b4d6-c29195951592@amd.com> Date: Mon, 2 Mar 2026 17:11:56 -0600 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/7] x86/sev: add support for enabling RMPOPT To: Dave Hansen , tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, peterz@infradead.org, thomas.lendacky@amd.com, herbert@gondor.apana.org.au, davem@davemloft.net, ardb@kernel.org Cc: pbonzini@redhat.com, aik@amd.com, Michael.Roth@amd.com, KPrateek.Nayak@amd.com, Tycho.Andersen@amd.com, Nathan.Fontenot@amd.com, jackyli@google.com, pgonda@google.com, rientjes@google.com, jacobhxu@google.com, xin@zytor.com, pawan.kumar.gupta@linux.intel.com, babu.moger@amd.com, dyoung@redhat.com, nikunj@amd.com, john.allen@amd.com, darwi@linutronix.de, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev References: <85aec55af41957678d214e9629eb6249b064fa87.1772486459.git.ashish.kalra@amd.com> <6a50d050-f602-43fd-a44a-cecedd9823eb@amd.com> <86bcca73-0c1b-405f-a72d-debb3c696333@intel.com> Content-Language: en-US From: "Kalra, Ashish" In-Reply-To: <86bcca73-0c1b-405f-a72d-debb3c696333@intel.com> Content-Type: text/plain; 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>>> ... >>> for_each_online_cpu(cpu) >>> wrmsrq_on_cpu(cpu, MSR_AMD64_RMPOPT_BASE, rmpopt_base); >>> >>> Then there's at least no ugly casting. >>> >> RMOPT_BASE MSRs don't need to be set serially, therefore, by >> using the cpu_online_mask and on_each_cpu_mask(), we can setup the MSRs >> concurrently and in parallel. Using for_each_online_cpu() will be slower than >> doing on_each_cpu_mask() as it doesn't send IPIs in parallel, right. > > If that's the case and you *need* performance, then please go add a > wrmsrq_on_cpumask() function to do things in parallel. Sure. Thanks, Ashish