From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B31F606B229 for ; Wed, 11 Nov 2026 14:58:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=FO0jzEGH; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=KlUwYzgX DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=WS+BOvXNnqjesrXQlbUlO4v0+iJ7/ISenb/dSRmXOIQ=; b=FO0jzEGHku7Wtu Fyesj5KWjCqDky1nEy+jweois0hMMjuo+Sqh5fCfLlFnmeOUPSAV8JZ0qlwXt0C3IeTFyFL9QUZ9J V9IpoLJobYsRgWdc+jc3IO6pwBYxKz4pbSUE25SrnLO89B8e35EwlfJbykUfRrhmKlXrN415Un2xt E3H0r2RPrSYil/ao+eqxj54hjS4r7uQxl0HdYt3rK61gz379qo2pcv25832W9yhC4AFCnyhVW3QdB xxNYuSQE3UmOZvEOagFlCHWvpQnfalFOZiqpG3fgRLFvE6lzLiHj070pD421JzAY7zOMhxusr2vtc SRD9Ni2vlmG2ieN/hrXA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xR9mf-000000071US-3q7E; Wed, 11 Nov 2026 14:58:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xR9mc-000000071Ru-1sqd for linux-arm-kernel@lists.infradead.org; Wed, 11 Nov 2026 14:58:43 +0000 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 BC72B1576; Wed, 11 Nov 2026 06:58:37 -0800 (PST) Received: from e122027.arm.com (unknown [10.57.58.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9BD533F632; Wed, 11 Nov 2026 06:58:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794409120; bh=LaJOVJB2rkRduR7O+9+vC56tNogP0ivGfTcT2Ms8OxY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KlUwYzgXi+VEPu9Iw4GmIu1XpN2UTJ+rmYbpura6Jm5aMPOWOoGzFevyTRewkrTad dNLZ2lTx4XzlF7QGRgjZ51QUE0uY64gsRLKrlsd1EEy8oYnr66JT2mLOqXNq2VrFd+ ItljTKKyaysM0xXoPuwrT5GD6Zk5oDpX8699rXno= 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 , WeiLin.Chang@arm.com, Lorenzo Pieralisi , Kohei Enju Subject: [PATCH v2 06/12] KVM: arm64: CCA: Add basic infrastructure for creating a realm Date: Wed, 11 Nov 2026 14:57:50 +0000 Message-ID: <20261111145758.217946-7-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261111145758.217946-1-steven.price@arm.com> References: <20261111145758.217946-1-steven.price@arm.com> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261111_065842_804539_C7109E86 X-CRM114-Status: GOOD ( 23.06 ) X-Spam-Score: -4.4 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Introduce the skeleton functions for creating and destroying a realm. The requested IPA size is checked against both the KVM and RMM limits. The actual work of constructing the realm will be added in future patches. Signed-off-by: Steven Price --- Changes since v1: - Cap the Realm IPA size at the smaller KVM and RMM limit, and record the selected IPA size when initializing Realm state. --- arch/arm64/include/asm/kvm_rmi.h | 20 +++++++++++ arch/arm64/kvm/arm.c | 9 +++++ arch/arm64/kvm/mmu.c | 18 ++++++++-- arch/arm64/kvm/rmi.c | 57 ++++++++++++++++++++++++++++++++ 4 files changed, 102 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_rmi.h index 3194daaacf2b..f1a1ed6b91f5 100644 --- a/arch/arm64/include/asm/kvm_rmi.h +++ b/arch/arm64/include/asm/kvm_rmi.h @@ -6,6 +6,9 @@ #ifndef __ASM_KVM_RMI_H #define __ASM_KVM_RMI_H +#include +#include + /** * enum realm_state - State of a Realm * @@ -50,12 +53,29 @@ enum realm_state { /** * struct realm - Additional per VM data for a Realm * + * @rd: Kernel mapping of the RMM-managed Realm Descriptor (RD) granule + * @sro: Preallocated SRO state context for Realm MMU operations * @state: The lifetime state machine for the realm + * @ia_bits: Number of valid Input Address bits in the IPA */ struct realm { + void *rd; + /* + * Reused by RTT map/unmap SRO commands. Those commands are only + * issued from Realm stage-2 map/unmap paths while kvm->mmu_lock is + * held for write, including Realm fault handling where + * kvm_fault_lock() takes the write side, so concurrent use is + * serialized. + */ + struct rmi_sro_state *sro; enum realm_state state; + unsigned int ia_bits; }; void kvm_init_rmi(void); +u32 kvm_rmm_ipa_limit(void); + +int kvm_init_realm(struct kvm *kvm); +void kvm_destroy_realm(struct kvm *kvm); #endif /* __ASM_KVM_RMI_H */ diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 318e8a4b19f8..b65a83ab31d8 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -303,6 +303,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) bitmap_zero(kvm->arch.vcpu_features, KVM_VCPU_MAX_FEATURES); + /* Initialise the realm bits after the generic bits are enabled */ + if (kvm_vm_is_realm(kvm)) { + ret = kvm_init_realm(kvm); + if (ret) + goto err_uninit_mmu; + } + return 0; err_uninit_mmu: @@ -367,6 +374,8 @@ void kvm_arch_destroy_vm(struct kvm *kvm) kvm_destroy_nested(kvm); kvm_arm_teardown_hypercalls(kvm); + if (kvm_vm_is_realm(kvm)) + kvm_destroy_realm(kvm); } static bool kvm_has_full_ptr_auth(void) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index c5aeb3a58417..9df3f8d5b4ef 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -981,10 +981,14 @@ static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = { static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type) { + struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu); u32 kvm_ipa_limit = get_kvm_ipa_limit(); u64 mmfr0, mmfr1; u32 phys_shift; + if (kvm_vm_is_realm(kvm)) + kvm_ipa_limit = min(kvm_ipa_limit, kvm_rmm_ipa_limit()); + phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type); if (is_protected_kvm_enabled()) { phys_shift = kvm_ipa_limit; @@ -1034,9 +1038,18 @@ static void stage2_destroy_range(struct kvm_pgtable *pgt, phys_addr_t addr, static void kvm_stage2_destroy(struct kvm_pgtable *pgt) { + struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu); unsigned int ia_bits = VTCR_EL2_IPA(pgt->mmu->vtcr); - stage2_destroy_range(pgt, 0, BIT(ia_bits)); + /* + * Realm RTTs are inaccessible to the host and may contain stale data + * after the RMM has released them. The non-root RTTs are explicitly + * destroyed through RMI before the RD is destroyed; only the root PGD + * pages remain to be freed here. + */ + if (!kvm_vm_is_realm(kvm)) + stage2_destroy_range(pgt, 0, BIT(ia_bits)); + KVM_PGT_FN(kvm_pgtable_stage2_destroy_pgd)(pgt); } @@ -1084,6 +1097,8 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t return -EINVAL; } + mmu->arch = &kvm->arch; + err = kvm_init_ipa_range(mmu, type); if (err) return err; @@ -1092,7 +1107,6 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t if (!pgt) return -ENOMEM; - mmu->arch = &kvm->arch; err = KVM_PGT_FN(kvm_pgtable_stage2_init)(pgt, mmu, &kvm_s2_mm_ops); if (err) goto out_free_pgtable; diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c index f4c45021c6f7..69c628cfb6c7 100644 --- a/arch/arm64/kvm/rmi.c +++ b/arch/arm64/kvm/rmi.c @@ -6,9 +6,66 @@ #include #include +#include +#include #include #include +u32 kvm_rmm_ipa_limit(void) +{ + return u64_get_bits(rmi_feat_reg(0), RMI_FEATURE_REGISTER_0_S2SZ); +} + +void kvm_destroy_realm(struct kvm *kvm) +{ + struct realm *realm = &kvm->arch.realm; + size_t pgd_size = kvm_pgtable_stage2_pgd_size(kvm->arch.mmu.vtcr); + + if (!kvm_realm_is_created(kvm)) { + kfree(realm->sro); + realm->sro = NULL; + return; + } + + kvm_set_realm_state(kvm, REALM_STATE_DYING); + + if (realm->rd) { + phys_addr_t rd_phys = virt_to_phys(realm->rd); + + if (WARN_ON(rmi_realm_terminate(rd_phys, realm->sro))) + return; + + if (WARN_ON(rmi_realm_destroy(rd_phys, realm->sro))) + return; + rmi_free_delegated_page(rd_phys); + realm->rd = NULL; + } + + if (WARN_ON(rmi_undelegate_range(kvm->arch.mmu.pgd_phys, + pgd_size))) + return; + + kvm_set_realm_state(kvm, REALM_STATE_DEAD); + + /* Now that the realm is destroyed, free the entry-level RTTs. */ + kvm_free_stage2_pgd(&kvm->arch.mmu); + + kfree(realm->sro); + realm->sro = NULL; +} + +int kvm_init_realm(struct kvm *kvm) +{ + struct realm *realm = &kvm->arch.realm; + + realm->ia_bits = VTCR_EL2_IPA(kvm->arch.mmu.vtcr); + realm->sro = kmalloc_obj(*realm->sro); + if (!realm->sro) + return -ENOMEM; + + return 0; +} + static int rmm_check_features(void) { if (kvm_lpa2_is_enabled() && -- 2.43.0