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AJvYcCWHMT5Z/CZwEEjACZBPfO3rIZD6UiOQlUHqzz2+3O2U4yvAe9dMFs9Iz/j3tEhfGZNt2fR7XPj3qEeCYFA=@vger.kernel.org X-Gm-Message-State: AOJu0Yw8LVEiWdM6xY0VSp+Ck/ItZpCN+Z2mAYkJ3zNWf+8kEOn/qRAW 4TMhzhtNEZjZpnINNSjev5zPF717y+OJB5T+IxJXkwBZU89PARuNx7Oeem0xHrNW/+rd3YKGV9B zH39axw== X-Google-Smtp-Source: AGHT+IEXfNMzWFuUnpYP1cCz6K5G+b+u3Xc0/pqStPWs0koB9KyFWEn1m6GJPyVim24B5D399fJqjTxhm1s= X-Received: from pjyr14.prod.google.com ([2002:a17:90a:e18e:b0:31c:2fe4:33b7]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:562b:b0:311:c939:c851 with SMTP id 98e67ed59e1d1-31f5de2e6dcmr1392130a91.4.1753829765637; Tue, 29 Jul 2025 15:56:05 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 29 Jul 2025 15:54:51 -0700 In-Reply-To: <20250729225455.670324-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250729225455.670324-1-seanjc@google.com> X-Mailer: git-send-email 2.50.1.552.g942d659e1b-goog Message-ID: <20250729225455.670324-21-seanjc@google.com> Subject: [PATCH v17 20/24] KVM: arm64: Enable support for guest_memfd backed memory From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Sean Christopherson Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, Ira Weiny , Gavin Shan , Shivank Garg , Vlastimil Babka , Xiaoyao Li , David Hildenbrand , Fuad Tabba , Ackerley Tng , Tao Chan , James Houghton Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Fuad Tabba Now that the infrastructure is in place, enable guest_memfd for arm64. * Select CONFIG_KVM_GUEST_MEMFD in KVM/arm64 Kconfig. * Enforce KVM_MEMSLOT_GMEM_ONLY for guest_memfd on arm64: Ensure that guest_memfd-backed memory slots on arm64 are only supported if they are intended for shared memory use cases (i.e., kvm_memslot_is_gmem_only() is true). This design reflects the current arm64 KVM ecosystem where guest_memfd is primarily being introduced for VMs that support shared memory. Reviewed-by: James Houghton Reviewed-by: Gavin Shan Reviewed-by: Marc Zyngier Acked-by: David Hildenbrand Signed-off-by: Fuad Tabba Signed-off-by: Sean Christopherson --- arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/mmu.c | 7 +++++++ 2 files changed, 8 insertions(+) diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 713248f240e0..bff62e75d681 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -37,6 +37,7 @@ menuconfig KVM select HAVE_KVM_VCPU_RUN_PID_CHANGE select SCHED_INFO select GUEST_PERF_EVENTS if PERF_EVENTS + select KVM_GUEST_MEMFD help Support hosting virtualized guest machines. =20 diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 8c82df80a835..85559b8a0845 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2276,6 +2276,13 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if ((new->base_gfn + new->npages) > (kvm_phys_size(&kvm->arch.mmu) >> PAG= E_SHIFT)) return -EFAULT; =20 + /* + * Only support guest_memfd backed memslots with mappable memory, since + * there aren't any CoCo VMs that support only private memory on arm64. + */ + if (kvm_slot_has_gmem(new) && !kvm_memslot_is_gmem_only(new)) + return -EINVAL; + hva =3D new->userspace_addr; reg_end =3D hva + (new->npages << PAGE_SHIFT); =20 --=20 2.50.1.552.g942d659e1b-goog