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X-CSE-ConnectionGUID: kiDLxCStS6OzsbDOggJE1w== X-CSE-MsgGUID: pwCT94pzSwOO+GAI+T3qrw== X-IronPort-AV: E=McAfee;i="6800,10657,11493"; a="55023478" X-IronPort-AV: E=Sophos;i="6.16,315,1744095600"; d="scan'208";a="55023478" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jul 2025 21:09:00 -0700 X-CSE-ConnectionGUID: AzIyrgphT4iDuvN4WCqAHQ== X-CSE-MsgGUID: qhm7N5zmQuuzHyzKWfIQMA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,315,1744095600"; d="scan'208";a="162938430" 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; 15 Jul 2025 21:08:45 -0700 Message-ID: Date: Wed, 16 Jul 2025 12:08:42 +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 , kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev Cc: 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: <20250715093350.2584932-3-tabba@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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. > The new name, KVM_GENERIC_GMEM_POPULATE, describes the purpose of the > option: to enable generic guest_memfd population mechanisms. This > improves clarity for developers and ensures the name accurately reflects > the functionality it controls, especially as guest_memfd support expands > beyond purely "private" memory scenarios. > > Reviewed-by: Ira Weiny > Reviewed-by: Gavin Shan > Reviewed-by: Shivank Garg > Reviewed-by: Vlastimil Babka > Co-developed-by: David Hildenbrand > Signed-off-by: David Hildenbrand > Signed-off-by: Fuad Tabba > --- > arch/x86/kvm/Kconfig | 6 +++--- > include/linux/kvm_host.h | 2 +- > virt/kvm/Kconfig | 2 +- > virt/kvm/guest_memfd.c | 2 +- > 4 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index 2eeffcec5382..df1fdbb4024b 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -46,7 +46,7 @@ config KVM_X86 > select HAVE_KVM_PM_NOTIFIER if PM > select KVM_GENERIC_HARDWARE_ENABLING > select KVM_GENERIC_PRE_FAULT_MEMORY > - select KVM_GENERIC_PRIVATE_MEM if KVM_SW_PROTECTED_VM > + select KVM_GENERIC_GMEM_POPULATE if KVM_SW_PROTECTED_VM > select KVM_WERROR if WERROR > > config KVM > @@ -95,7 +95,7 @@ config KVM_SW_PROTECTED_VM > config KVM_INTEL > tristate "KVM for Intel (and compatible) processors support" > depends on KVM && IA32_FEAT_CTL > - select KVM_GENERIC_PRIVATE_MEM if INTEL_TDX_HOST > + select KVM_GENERIC_GMEM_POPULATE if INTEL_TDX_HOST > select KVM_GENERIC_MEMORY_ATTRIBUTES if INTEL_TDX_HOST > help > Provides support for KVM on processors equipped with Intel's VT > @@ -157,7 +157,7 @@ config KVM_AMD_SEV > depends on KVM_AMD && X86_64 > depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m) > select ARCH_HAS_CC_PLATFORM > - select KVM_GENERIC_PRIVATE_MEM > + select KVM_GENERIC_GMEM_POPULATE > select HAVE_KVM_ARCH_GMEM_PREPARE > select HAVE_KVM_ARCH_GMEM_INVALIDATE > help > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 755b09dcafce..359baaae5e9f 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -2556,7 +2556,7 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm, > int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order); > #endif > > -#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM > +#ifdef CONFIG_KVM_GENERIC_GMEM_POPULATE > /** > * kvm_gmem_populate() - Populate/prepare a GPA range with guest data > * > diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig > index 49df4e32bff7..559c93ad90be 100644 > --- a/virt/kvm/Kconfig > +++ b/virt/kvm/Kconfig > @@ -116,7 +116,7 @@ config KVM_GMEM > select XARRAY_MULTI > bool > > -config KVM_GENERIC_PRIVATE_MEM > +config KVM_GENERIC_GMEM_POPULATE > select KVM_GENERIC_MEMORY_ATTRIBUTES > select KVM_GMEM > bool > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > index b2aa6bf24d3a..befea51bbc75 100644 > --- a/virt/kvm/guest_memfd.c > +++ b/virt/kvm/guest_memfd.c > @@ -638,7 +638,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, > } > EXPORT_SYMBOL_GPL(kvm_gmem_get_pfn); > > -#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM > +#ifdef CONFIG_KVM_GENERIC_GMEM_POPULATE > long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long npages, > kvm_gmem_populate_cb post_populate, void *opaque) > {