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X-CSE-ConnectionGUID: XP0hD86kRMGdbkfQ4MUwGA== X-CSE-MsgGUID: 6KPrFpDFQwqlxgoK5x9yGg== X-IronPort-AV: E=McAfee;i="6800,10657,11493"; a="65955342" X-IronPort-AV: E=Sophos;i="6.16,315,1744095600"; d="scan'208";a="65955342" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2025 01:31:33 -0700 X-CSE-ConnectionGUID: nVOQ/N/PSSSwhIizbLv+DA== X-CSE-MsgGUID: O80dBXWoQ8GoQDCI749OMQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,315,1744095600"; d="scan'208";a="162986525" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.247.1]) ([10.124.247.1]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2025 01:31:18 -0700 Message-ID: <418ddbbd-c25e-4047-9317-c05735e02807@intel.com> Date: Wed, 16 Jul 2025 16:31:15 +0800 Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v14 02/21] KVM: Rename CONFIG_KVM_GENERIC_PRIVATE_MEM to CONFIG_KVM_GENERIC_GMEM_POPULATE To: Fuad Tabba Cc: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev, pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, peterx@redhat.com, pankaj.gupta@amd.com, ira.weiny@intel.com References: <20250715093350.2584932-1-tabba@google.com> <20250715093350.2584932-3-tabba@google.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/16/2025 4:11 PM, Fuad Tabba wrote: > On Wed, 16 Jul 2025 at 05:09, Xiaoyao Li wrote: >> On 7/15/2025 5:33 PM, Fuad Tabba wrote: >>> The original name was vague regarding its functionality. This Kconfig >>> option specifically enables and gates the kvm_gmem_populate() function, >>> which is responsible for populating a GPA range with guest data. >> Well, I disagree. >> >> The config KVM_GENERIC_PRIVATE_MEM was introduced by commit 89ea60c2c7b5 >> ("KVM: x86: Add support for "protected VMs" that can utilize private >> memory"), which is a convenient config for vm types that requires >> private memory support, e.g., SNP, TDX, and KVM_X86_SW_PROTECTED_VM. >> >> It was commit e4ee54479273 ("KVM: guest_memfd: let kvm_gmem_populate() >> operate only on private gfns") that started to use >> CONFIG_KVM_GENERIC_PRIVATE_MEM gates kvm_gmem_populate() function. But >> CONFIG_KVM_GENERIC_PRIVATE_MEM is not for kvm_gmem_populate() only. >> >> If using CONFIG_KVM_GENERIC_PRIVATE_MEM to gate kvm_gmem_populate() is >> vague and confusing, we can introduce KVM_GENERIC_GMEM_POPULATE to gate >> kvm_gmem_populate() and select KVM_GENERIC_GMEM_POPULATE under >> CONFIG_KVM_GENERIC_PRIVATE_MEM. >> >> Directly replace CONFIG_KVM_GENERIC_PRIVATE_MEM with >> KVM_GENERIC_GMEM_POPULATE doesn't look correct to me. > I'll quote David's reply to an earlier version of this patch [*]: It's not related to my concern. My point is that CONFIG_KVM_GENERIC_PRIVATE_MEM is used for selecting the private memory support. Rename it to KVM_GENERIC_GMEM_POPULATE is not correct. Current code uses CONFIG_KVM_GENERIC_PRIVATE_MEM to gate kvm_gmem_populate() because kvm_gmem_populate() requires both gmem and memory attributes support and CONFIG_KVM_GENERIC_PRIVATE_MEM can ensure it. But CONFIG_KVM_GENERIC_PRIVATE_MEM was not only for gating kvm_gmem_populate(). >>> I'm curious what generic means in this name? >> That an architecture wants to use the generic version and not provide >> it's own alternative implementation. >> >> We frequently use that term in this context, see GENERIC_IOREMAP as one >> example. > [*]https://lore.kernel.org/all/b6355951-5f9d-4ca9-850f-79e767d8caa2@redhat.com/ > > Thanks, > /fuad