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=1794409121; b=1cY70MOPnrxtFG6IcoedQ+zx/Orycu9DbsXk60xUeTSc9SiXUwNZm69qfXOxoBQbtXEE SRBIBdW0r2akJYJ1C7/VjGCh0YT6glLZfG3NYKbQAsxka/32wPZ/lbA8I5zP5JtBqEqMU o+BBbOrUEx4EGHfJ7P2/KtTGzgFTdKXht230y2TuqKkQLeI8Kw+GPWhfI0UIRctWfBPQg UYXZm0i5cTg+vaHtLT9X6zth5Dy4o/KmSSaTD/+BOw4gKr+YeT1CpaOPInmH/Onq/Y32T qWp5XSKZo2B0GoOawxq9RQiwHWVEpY5eWazhvU9TMGRWqEEx6KxWsdeflhk2rCzNGOg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794409121; 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=WS+BOvXNnqjesrXQlbUlO4v0+iJ7/ISenb/dSRmXOIQ=; b=Uyzjyspan5w4nzTNnw5sJ+oJYQhey3Jddm2iZ3gFWNLgtxrOSukWjY1zf19O1+huq3UV z3CM43tSxi+ikUlF2w3ND5AG6RKJBo0P5g+wSYFUMPcSNCJYeWWiUdNmOkPM/BiBoSvMj TOdsnDIidA3RH8wtrVlKbYW/5H48MCnYEC6jmteWHDrbPFZOKEmtsuys2H/xfxCbsFUf/ bdgsuYsBdQgFGkxgORB3zBjn/y4tFMTkSaIF084cEqP048AHyi5syojaEzmHDzp5gpxoz JDNIn/lx3zsoZch80SjJPDprbx4q2xZDnSQQPH27EHLHPPGFZwgpkyJSECOgyQpWBVA== 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=KlUwYzgX; 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 599F860A2604; Wed, 11 Nov 2026 14:58:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 599F860A2604 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) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=KlUwYzgX 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-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 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