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X-CSE-ConnectionGUID: Ahtx2z5wStO9xMrwBr4l+A== X-CSE-MsgGUID: EHyNB14OQVehg9HDz+H/lQ== X-IronPort-AV: E=McAfee;i="6800,10657,11800"; a="91962505" X-IronPort-AV: E=Sophos;i="6.24,174,1774335600"; d="scan'208";a="91962505" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2026 12:50:50 -0700 X-CSE-ConnectionGUID: iUirwk8QQliHxUgn3fd68A== X-CSE-MsgGUID: ubT0feRzTeKbG/jFHV3mKA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,174,1774335600"; d="scan'208";a="242800016" Received: from mvcheng-desk2.amr.corp.intel.com (HELO [10.125.111.73]) ([10.125.111.73]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2026 12:50:49 -0700 Message-ID: Date: Thu, 28 May 2026 12:50:16 -0700 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 2/7] x86/msr: add wrmsrq_on_cpus helper To: "Kalra, Ashish" , Borislav Petkov Cc: tglx@kernel.org, mingo@redhat.com, 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, pbonzini@redhat.com, aik@amd.com, Michael.Roth@amd.com, KPrateek.Nayak@amd.com, Tycho.Andersen@amd.com, Nathan.Fontenot@amd.com, ackerleytng@google.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: <20260527210603.GCahdcu8zvVjfKfGEL@fat_crate.local> <20260528004332.GDahePtGqVp2boiEJL@fat_crate.local> <2d164e19-5cc6-47ca-9150-f4d432dd10c4@amd.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/28/26 12:37, Kalra, Ashish wrote: > A simple loop would be perfectly fine and avoids the need for the wrmsrq_on_cpus() helper entirely: > > for_each_cpu(cpu, &rmpopt_cpumask) > wrmsrq_on_cpu(cpu, MSR_AMD64_RMPOPT_BASE, rmpopt_base); I'm glad we're on the same page finally. I just hope we can get to this point more quickly next time. I started off with exactly this suggestion, but someone chimed in to the thread and said it was "slower": > https://lore.kernel.org/lkml/6a50d050-f602-43fd-a44a-cecedd9823eb@amd.com/