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X-CSE-ConnectionGUID: 3x2roPuXQN6yJPLNJnAPLg== X-CSE-MsgGUID: 2XfYa+pkRyysW5DYhZGkzQ== X-IronPort-AV: E=McAfee;i="6800,10657,11493"; a="72450042" X-IronPort-AV: E=Sophos;i="6.16,315,1744095600"; d="scan'208";a="72450042" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jul 2025 22:19:11 -0700 X-CSE-ConnectionGUID: j7EXiFajTcaQq4oFn8LIVg== X-CSE-MsgGUID: 2VAAn0VzTD6hSHKhcdVWfA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,315,1744095600"; d="scan'208";a="156804591" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.247.1]) ([10.124.247.1]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jul 2025 22:18:55 -0700 Message-ID: Date: Wed, 16 Jul 2025 13:18:51 +0800 Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v14 04/21] KVM: x86: Introduce kvm->arch.supports_gmem 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> <20250715093350.2584932-5-tabba@google.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20250715093350.2584932-5-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: > Introduce a new boolean member, supports_gmem, to kvm->arch. > > Previously, the has_private_mem boolean within kvm->arch was implicitly > used to indicate whether guest_memfd was supported for a KVM instance. > However, with the broader support for guest_memfd, it's not exclusively > for private or confidential memory. Therefore, it's necessary to > distinguish between a VM's general guest_memfd capabilities and its > support for private memory. > > This new supports_gmem member will now explicitly indicate guest_memfd > support for a given VM, allowing has_private_mem to represent only > support for private memory. > > 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 Reviewed-by: Xiaoyao Li Btw, it seems that supports_gmem can be enabled for all the types of VM? Even without mmap support, allow all the types of VM to create guest_memfd seems not something wrong. It's just that the guest_memfd allocated might not be used, e.g., for KVM_X86_DEFAULT_VM.