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AJvYcCUOvKoc0QYP+cVIeA7vQEWKGb4FJ7yomifXKsvjEpQmLfP/sESn9iwvN5uGVO3Vlg8zkj+Ld16Ry2kiKUC4@vger.kernel.org X-Gm-Message-State: AOJu0YwUe3m1Xx/8V6KkpihitVWQEvl8Bl6YSVt+l2NnTx42GupolbLn gDjL+wSk8b7m9SAXr4gJ95text+Jm7wtHxcDYKsTdakOl+qlNNe7fxI6HS9w7YZZbdiDgoM2tEq pTQ== X-Google-Smtp-Source: AGHT+IHjMKXCvTmBxoiQUc3S0//vqXVb77uBJR4SvhxKOwINqq6jYrFaYhNl/XwH/tFcftUafwOB/rmHeg== X-Received: from wmbhc7.prod.google.com ([2002:a05:600c:8707:b0:442:f482:bba5]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:1e89:b0:44b:eb56:1d45 with SMTP id 5b1f17b1804b1-451f0aa7ff9mr75040805e9.15.1749137913905; Thu, 05 Jun 2025 08:38:33 -0700 (PDT) Date: Thu, 5 Jun 2025 16:37:57 +0100 In-Reply-To: <20250605153800.557144-1-tabba@google.com> Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250605153800.557144-1-tabba@google.com> X-Mailer: git-send-email 2.49.0.1266.g31b7d2e469-goog Message-ID: <20250605153800.557144-16-tabba@google.com> Subject: [PATCH v11 15/18] KVM: arm64: Enable host mapping of shared guest_memfd memory 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 Enable the host mapping of guest_memfd-backed memory on arm64. This applies to all current arm64 VM types that support guest_memfd. Future VM types can restrict this behavior via the kvm_arch_gmem_supports_shared_mem() hook if needed. Acked-by: David Hildenbrand Signed-off-by: Fuad Tabba Reviewed-by: James Houghton --- arch/arm64/include/asm/kvm_host.h | 5 +++++ arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/mmu.c | 7 +++++++ 3 files changed, 13 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 08ba91e6fb03..8add94929711 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1593,4 +1593,9 @@ static inline bool kvm_arch_has_irq_bypass(void) return true; } +#ifdef CONFIG_KVM_GMEM +#define kvm_arch_supports_gmem(kvm) true +#define kvm_arch_supports_gmem_shared_mem(kvm) IS_ENABLED(CONFIG_KVM_GMEM_SHARED_MEM) +#endif + #endif /* __ARM64_KVM_HOST_H__ */ diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 096e45acadb2..8c1e1964b46a 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -38,6 +38,7 @@ menuconfig KVM select HAVE_KVM_VCPU_RUN_PID_CHANGE select SCHED_INFO select GUEST_PERF_EVENTS if PERF_EVENTS + select KVM_GMEM_SHARED_MEM help Support hosting virtualized guest machines. diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index f14925fe6144..19aca1442bbf 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2281,6 +2281,13 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if ((new->base_gfn + new->npages) > (kvm_phys_size(&kvm->arch.mmu) >> PAGE_SHIFT)) return -EFAULT; + /* + * Only support guest_memfd backed memslots with shared memory, since + * there aren't any CoCo VMs that support only private memory on arm64. + */ + if (kvm_slot_has_gmem(new) && !kvm_gmem_memslot_supports_shared(new)) + return -EINVAL; + hva = new->userspace_addr; reg_end = hva + (new->npages << PAGE_SHIFT);