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X-CSE-ConnectionGUID: tnOl/5TjQXGzGAdPhcXu6Q== X-CSE-MsgGUID: DhDdLTnnQKGcqJ5b5x4tnA== X-IronPort-AV: E=McAfee;i="6800,10657,11493"; a="55026235" X-IronPort-AV: E=Sophos;i="6.16,315,1744095600"; d="scan'208";a="55026235" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jul 2025 22:07:57 -0700 X-CSE-ConnectionGUID: 42ThZuFZT06jHaEFVlQWfw== X-CSE-MsgGUID: /IlBCgamRSmR6+bWLAGcGg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,315,1744095600"; d="scan'208";a="188408979" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.247.1]) ([10.124.247.1]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jul 2025 22:07:43 -0700 Message-ID: <83d124c1-2d1d-4ba4-a72b-82a008a97301@intel.com> Date: Wed, 16 Jul 2025 13:07:38 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v14 03/21] KVM: 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> <20250715093350.2584932-4-tabba@google.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20250715093350.2584932-4-tabba@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: hj8zz8zb998dj5984rhsj41wf4bjix8d X-Rspam-User: X-Rspamd-Queue-Id: 7C4772000B X-Rspamd-Server: rspam02 X-HE-Tag: 1752642479-205869 X-HE-Meta: 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 FipjA5fo j1up0X+OXCLgWM456UCGHEJJxvMP3v/jL1/eOz87cK6fEoVti7zaQKDm7eIfN4ZrHoOO/NKUxSVYutU5gbujsQ0FEZhxUBbh/cU1sx5HdnvR2TYt0FlYaKUKwEVirZkgvAxip41Pt37RcSJfmLseWoSQV4zhIpdvHfnt1WOXQ/BQtgcWxLeowdw1sonRce6tz+vnbDnicM69p0rm3RMOI/xbPX0IQrbUfxJ2kpG1ZfN92nO+b9bawZHmxhY/PRPpig6Hq5Lgbd3OQD+wWNc0wyOoGk9VWasUQa/fE2asUAYQ88BeFt3OzCryrF49W2ISmkgRNXufHLZKE17MkAnpTZXK7xprOk4nA72JrO1Ca0KQZ+gsGl+sPHp3d/b10v/0b4bfYnxHS/QGxn1zOWj8vrMn5plmWS9tpp+C3 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/15/2025 5:33 PM, Fuad Tabba wrote: > Introduce kvm_arch_supports_gmem() to explicitly indicate whether an > architecture supports guest_memfd. > > Previously, kvm_arch_has_private_mem() was used to check for guest_memfd > support. However, this conflated guest_memfd with "private" memory, > implying that guest_memfd was exclusively for CoCo VMs or other private > memory use cases. > > With the expansion of guest_memfd to support non-private memory, such as > shared host mappings, it is necessary to decouple these concepts. The > new kvm_arch_supports_gmem() function provides a clear way to check for > guest_memfd support. > > 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/include/asm/kvm_host.h | 4 +++- > include/linux/kvm_host.h | 11 +++++++++++ > virt/kvm/kvm_main.c | 4 ++-- > 3 files changed, 16 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index acb25f935d84..bde811b2d303 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -2277,8 +2277,10 @@ void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level, > > #ifdef CONFIG_KVM_GMEM > #define kvm_arch_has_private_mem(kvm) ((kvm)->arch.has_private_mem) > +#define kvm_arch_supports_gmem(kvm) kvm_arch_has_private_mem(kvm) > #else > #define kvm_arch_has_private_mem(kvm) false > +#define kvm_arch_supports_gmem(kvm) false > #endif > > #define kvm_arch_has_readonly_mem(kvm) (!(kvm)->arch.has_protected_state) > @@ -2331,7 +2333,7 @@ enum { > #define HF_SMM_INSIDE_NMI_MASK (1 << 2) > > # define KVM_MAX_NR_ADDRESS_SPACES 2 > -/* SMM is currently unsupported for guests with private memory. */ > +/* SMM is currently unsupported for guests with guest_memfd private memory. */ Please don't change the comment. As below, it checks kvm_arch_has_private_mem(). Nothing to do with guest_memfd. Otherwise, Reviewed-by: Xiaoyao Li > # define kvm_arch_nr_memslot_as_ids(kvm) (kvm_arch_has_private_mem(kvm) ? 1 : 2) > # define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0) > # define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm)