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V" , Emi Kisanuki , Vishal Annapurve Subject: [PATCH v13 23/48] KVM: arm64: Expose support for private memory Date: Wed, 18 Mar 2026 15:53:47 +0000 Message-ID: <20260318155413.793430-24-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260318155413.793430-1-steven.price@arm.com> References: <20260318155413.793430-1-steven.price@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260318_155553_774609_6806D033 X-CRM114-Status: GOOD ( 11.10 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Select KVM_GENERIC_MEMORY_ATTRIBUTES and provide the necessary support functions. Signed-off-by: Steven Price --- Changes since v12: * Only define kvm_arch_has_private_mem() when CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES is set to avoid build issues when KVM is disabled. Changes since v10: * KVM_GENERIC_PRIVATE_MEM replacd with KVM_GENERIC_MEMORY_ATTRIBUTES. Changes since v9: * Drop the #ifdef CONFIG_KVM_PRIVATE_MEM guard from the definition of kvm_arch_has_private_mem() Changes since v2: * Switch kvm_arch_has_private_mem() to a macro to avoid overhead of a function call. * Guard definitions of kvm_arch_{pre,post}_set_memory_attributes() with #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES. * Early out in kvm_arch_post_set_memory_attributes() if the WARN_ON should trigger. --- arch/arm64/include/asm/kvm_host.h | 4 ++++ arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/mmu.c | 24 ++++++++++++++++++++++++ 3 files changed, 29 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 64304848aad4..1efea996f474 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1486,6 +1486,10 @@ struct kvm *kvm_arch_alloc_vm(void); #define vcpu_is_protected(vcpu) kvm_vm_is_protected((vcpu)->kvm) +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +#define kvm_arch_has_private_mem(kvm) ((kvm)->arch.is_realm) +#endif + int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature); bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 4f803fd1c99a..1cac6dfc0972 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -38,6 +38,7 @@ menuconfig KVM select SCHED_INFO select GUEST_PERF_EVENTS if PERF_EVENTS select KVM_GUEST_MEMFD + select KVM_GENERIC_MEMORY_ATTRIBUTES help Support hosting virtualized guest machines. diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index b705ad6c6c8b..bad93938acdb 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2494,6 +2494,30 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return ret; } +#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES +bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range) +{ + WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm)); + return false; +} + +bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, + struct kvm_gfn_range *range) +{ + if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm))) + return false; + + if (range->arg.attributes & KVM_MEMORY_ATTRIBUTE_PRIVATE) + range->attr_filter = KVM_FILTER_SHARED; + else + range->attr_filter = KVM_FILTER_PRIVATE; + kvm_unmap_gfn_range(kvm, range); + + return false; +} +#endif + void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) { } -- 2.43.0