From nobody Mon Apr 6 18:24:01 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A717D3FE656; Wed, 18 Mar 2026 15:55:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773849357; cv=none; b=KdfGpmWrwchgckKUzq/mfT+ocg04s5nZbpKZgv1hbsDe39Icx/Hs3WKhxI0KcMMTLoJ+O9jZlUnbHMWlSLqBojZJP1bry+Fa3gaeeaHe9kfyelD5EiIjYvaBwpBZzsb37xISAEn4QPrSFoFy2Eo80U1bhwicqeVo3Q/K1a/ohb8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773849357; c=relaxed/simple; bh=9pnW0KHBXe2eZkXZnH5GzrFsaF10++mbuJBDirGOo78=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hz3vW1GsDdzwFC4/DdOapfqBQ/K5jcB0e8PiPhpP8UF1cgLH4sQIye0Bd7xbmL3tbKqWZzPPGG9rx1OH65DtyATvdVcLSAzLVrceGHSQhv5KyA0w07b9d4bxk7Jl8LXQNAWvMz89yyLmrTu1xYrgZW3Pu9lBuVKklK4leNsRz18= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B788222BE; Wed, 18 Mar 2026 08:55:43 -0700 (PDT) Received: from e122027.arm.com (unknown [10.57.61.122]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 76F4E3F73B; Wed, 18 Mar 2026 08:55:46 -0700 (PDT) From: Steven Price To: kvm@vger.kernel.org, kvmarm@lists.linux.dev Cc: Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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); =20 #define vcpu_is_protected(vcpu) kvm_vm_is_protected((vcpu)->kvm) =20 +#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); =20 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. =20 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; } =20 +#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 =3D KVM_FILTER_SHARED; + else + range->attr_filter =3D 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) { } --=20 2.43.0