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AJvYcCUQOH3GQF21BhEdWql/VgCkt3K3oYAvN07qKcU6rSmZd2mIiBUgGVaqInVbrDzLWm4nUpRtIDY=@lists.linux.dev X-Gm-Message-State: AOJu0Yz+kuHxEqCH7LSjSAv4XW4o5Yl0oZegEyxT9oODU+lUl6c240Yq /a02+f4qjatmp+TzYjvdkhhbIJc6zdYu7j9xsxD7TWI9vFUBo1gyXEtfw52sqKyNKG1ZVTYRSW0 nUg== X-Google-Smtp-Source: AGHT+IEXYs7T9kwp4zt9Q6duZzuD37c0z/m16xiUI6ublpH8MZEPzSJPqggoJ+YdDeQOgE64Wo1Xc33Ecg== X-Received: from edip15.prod.google.com ([2002:a50:cd8f:0:b0:60c:7ccc:867c]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:4308:b0:606:dee2:42df with SMTP id 4fb4d7f45d1cf-611e8490658mr14145606a12.17.1752572038209; Tue, 15 Jul 2025 02:33:58 -0700 (PDT) Date: Tue, 15 Jul 2025 10:33:32 +0100 In-Reply-To: <20250715093350.2584932-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250715093350.2584932-1-tabba@google.com> X-Mailer: git-send-email 2.50.0.727.gbf7dc18ff4-goog Message-ID: <20250715093350.2584932-4-tabba@google.com> Subject: [PATCH v14 03/21] KVM: Introduce kvm_arch_supports_gmem() From: Fuad Tabba To: 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, xiaoyao.li@intel.com, 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, tabba@google.com Content-Type: text/plain; charset="UTF-8" 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. */ # 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) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 359baaae5e9f..ab1bde048034 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -729,6 +729,17 @@ static inline bool kvm_arch_has_private_mem(struct kvm *kvm) } #endif +/* + * Arch code must define kvm_arch_supports_gmem if support for guest_memfd is + * enabled. + */ +#if !defined(kvm_arch_supports_gmem) && !IS_ENABLED(CONFIG_KVM_GMEM) +static inline bool kvm_arch_supports_gmem(struct kvm *kvm) +{ + return false; +} +#endif + #ifndef kvm_arch_has_readonly_mem static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm) { diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d5f0ec2d321f..162e2a69cc49 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1588,7 +1588,7 @@ static int check_memory_region_flags(struct kvm *kvm, { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; - if (kvm_arch_has_private_mem(kvm)) + if (kvm_arch_supports_gmem(kvm)) valid_flags |= KVM_MEM_GUEST_MEMFD; /* Dirty logging private memory is not currently supported. */ @@ -4915,7 +4915,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg) #endif #ifdef CONFIG_KVM_GMEM case KVM_CAP_GUEST_MEMFD: - return !kvm || kvm_arch_has_private_mem(kvm); + return !kvm || kvm_arch_supports_gmem(kvm); #endif default: break; -- 2.50.0.727.gbf7dc18ff4-goog