From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793628839; b=1lK45SAuN0T8weX9dwGaVztrYH4yJzLYGSG1xGqrT3CHzJrnwiXn9UOEMmhZhI8oqFW6 yEVTbU0fLA3NExrM/J4bCeWDmZzJGbC7RVCdd64/VXKkbMjGdco1xzbEnD55yf88dWu52 ht1c8BNj9hN8cC6ncnTubMDYT+IXPO9XXLv1t6oaZxRAtQAq+lKscbnToHZHuql5rKZMf 1Pm+CGexJXEwp34acqOyu+0+fgYJOcFc/RQpkZd/dYIpwVZ/4uBJUBPIWmPnEtDWrFUJI 1Hw/++kxsQsW6HPVnxmL6VtudExKcaJhymiSNw2iFejLq4yBgjheos5nCpq0EXLKIVw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793628839; h=DMARC-Filter:Received:Received:DKIM-Signature:From:To:Cc:Subject: Date:Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=P7s5fTYbabCx65o9vZqOXbEWaMwo2qqeJ1k/3DDHPeg=; b=Vguc+9Bh809YJNh6FHIkODcPYZCtMr94bFSLk4+HjM2JtHJtMcdPMvEXmYxQscPjyzY7 +uJa0ZCfwnUCrAWwWQ3b8d7yidTRY0R1yIayqeyEB4ze9r002PTBzQlyew9+pXmzy42j0 aAu9tQ/xJDPFwrGE9coWrbrKdFIR6fLHYCX39SlANTJ2+D4hrrhr1isEOMwsNUj0CgcUn aoNsI0lS/n5i4brtmQQJK9ykhRNWS0D7Os++OrngR5ZZ+ds/G5uiha+I38GaZpV4sZBbm XS2lr8wnxLnQFsKONbAFgQTuOB9pFJarYxrwwzCmSl18FUWKgCPU6hMfrFA+e8ci6yA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=jErUH5qQ; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id AC59D60A2607; Mon, 2 Nov 2026 14:13:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org AC59D60A2607 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=jErUH5qQ 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 E716D1691; Mon, 2 Nov 2026 06:13:54 -0800 (PST) Received: from e122027.arm.com (unknown [10.57.58.9]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 33E273F59E; Mon, 2 Nov 2026 06:13:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1793628838; bh=yKWmeyNxwmUK+L/EPoppbmafGzFD1IiTBcY7YvGJPYw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jErUH5qQcDMkfm+742/DyqdPY5qpqOpoY8e/WOp2e3TO0ciRvmUUKejg4nul2aZZ/ TOV6gDOvms5ktgs20ntV2b3NL8N8ssLZuZfvEfRLFiodpM10QCzxOs19vhevbDpKWU R9ke8vqq763JW06yL4AJD2VrHwMiZi04sH1WD5RM= 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 Subject: [PATCH 06/11] KVM: arm64: CCA: Add basic infrastructure for creating a realm Date: Mon, 2 Nov 2026 14:12:57 +0000 Message-ID: <20261102141304.126883-7-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261102141304.126883-1-steven.price@arm.com> References: <20261102141304.126883-1-steven.price@arm.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Introduce the skeleton functions for creating and destroying a realm. The IPA size requested is checked against what the RMM supports. The actual work of constructing the realm will be added in future patches. Signed-off-by: Steven Price --- 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 | 56 ++++++++++++++++++++++++++++++++ 4 files changed, 101 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 c8599fed5902..9a7bbfaf9675 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 1301c563d705..b049ea67d9af 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 = 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 5b07beff8bc9..45ecbaa467d1 100644 --- a/arch/arm64/kvm/rmi.c +++ b/arch/arm64/kvm/rmi.c @@ -6,6 +6,8 @@ #include #include +#include +#include #include #include @@ -14,6 +16,60 @@ static bool rmi_has_feature(int reg, unsigned long feature) return !!u64_get_bits(rmi_feat_reg(reg), feature); } +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->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