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X-CSE-ConnectionGUID: HgEWt9ghQyu3zSGUIgXNgg== X-CSE-MsgGUID: +CbGrzt6SJWkomAKrpCRPA== X-IronPort-AV: E=McAfee;i="6800,10657,11744"; a="86532130" X-IronPort-AV: E=Sophos;i="6.23,150,1770624000"; d="scan'208";a="86532130" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2026 15:38:48 -0700 X-CSE-ConnectionGUID: THD89Wr5T66a4xS9yJYAXg== X-CSE-MsgGUID: snb9CbzCRziWHzsivKtP2w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,150,1770624000"; d="scan'208";a="223307417" Received: from schen9-mobl4.amr.corp.intel.com (HELO [10.125.111.27]) ([10.125.111.27]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Mar 2026 15:38:45 -0700 Message-ID: <4bbc9ab2-1450-4bd1-982d-3f4ca2cc04f6@intel.com> Date: Mon, 30 Mar 2026 15:38:51 -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 v3 2/6] x86/sev: Add support for enabling RMPOPT To: Ashish Kalra , 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: <0f6539b8fd4c4e7d40fb19e6b3255a120664bfb4.1774755884.git.ashish.kalra@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 3/30/26 15:26, Ashish Kalra wrote: > From: Ashish Kalra > > The new RMPOPT instruction helps manage per-CPU RMP optimization > structures inside the CPU. It takes a 1GB-aligned physical address > and either returns the status of the optimizations or tries to enable > the optimizations. > > Per-CPU RMPOPT tables support at most 2 TB of addressable memory for > RMP optimizations. > > Initialize the per-CPU RMPOPT table base to the starting physical > address. This enables RMP optimization for up to 2 TB of system RAM on > all CPUs. Isn't the Subject: more appropriately something like: x86/sev: Initialize RMPOPT configuration MSRs The subject is too generic as-is. > diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h > index be3e3cc963b2..9c8a6dfd7891 100644 > --- a/arch/x86/include/asm/msr-index.h > +++ b/arch/x86/include/asm/msr-index.h > @@ -758,6 +758,9 @@ > #define MSR_AMD64_SEG_RMP_ENABLED_BIT 0 > #define MSR_AMD64_SEG_RMP_ENABLED BIT_ULL(MSR_AMD64_SEG_RMP_ENABLED_BIT) > #define MSR_AMD64_RMP_SEGMENT_SHIFT(x) (((x) & GENMASK_ULL(13, 8)) >> 8) > +#define MSR_AMD64_RMPOPT_BASE 0xc0010139 > +#define MSR_AMD64_RMPOPT_ENABLE_BIT 0 > +#define MSR_AMD64_RMPOPT_ENABLE BIT_ULL(MSR_AMD64_RMPOPT_ENABLE_BIT) > > #define MSR_SVSM_CAA 0xc001f000 > > diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c > index e35fac0a8a3d..dc6a8e102cdc 100644 > --- a/arch/x86/virt/svm/sev.c > +++ b/arch/x86/virt/svm/sev.c > @@ -477,6 +477,30 @@ static bool __init setup_rmptable(void) > return true; > } > > +static __init void configure_and_enable_rmpopt(void) > +{ Nit: just "setup_rmpopt()" would be fine, IMNHO. We have plenty of "setup_foo()" functions that configure and enable CPU features. > + phys_addr_t pa_start = ALIGN_DOWN(PFN_PHYS(min_low_pfn), SZ_1G); > + u64 rmpopt_base = pa_start | MSR_AMD64_RMPOPT_ENABLE; > + int cpu; > + > + if (!cpu_feature_enabled(X86_FEATURE_RMPOPT)) > + return; > + > + if (!(rmp_cfg & MSR_AMD64_SEG_RMP_ENABLED)) { > + pr_notice("RMPOPT optimizations not enabled, segmented RMP required\n"); > + return; > + } > + > + /* > + * Per-CPU RMPOPT tables support at most 2 TB of addressable memory > + * for RMP optimizations. Initialize the per-CPU RMPOPT table base > + * to the starting physical address to enable RMP optimizations for > + * up to 2 TB of system RAM on all CPUs. > + */ > + for_each_online_cpu(cpu) > + wrmsrq_on_cpu(cpu, MSR_AMD64_RMPOPT_BASE, rmpopt_base); > +} > + With those nits fixed: Reviewed-by: Dave Hansen