From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id ABF70431A33; Mon, 3 Aug 2026 13:46:24 +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=1785764786; cv=none; b=dh8p90eYs/PVzk7MJvdphrojpuZjhFEwoDB6TYGrgjeJfGpcjLU2a/BxRxu2yLzmPM1MNqs5J1GxvgqoxsJQNqMBxGeQT+6BJyj0H2Jlz3t5dyK1Enas+n7SxJ5SgoLGGbezmlu1ziGhtWdhBFdF/uAuAWsVQGUKYjdlSPfII+M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785764786; c=relaxed/simple; bh=eKE4/Sm5/GuxJ8UFVqD6W1rOa6RVJlIeYRdiWlAXcYM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZigbDDfS3L99jX1buyQu8rZwVX+wBGmsq7wudExKVp4gvxNIwmKszJW35baoRkcj30BlZl0fCUgoN1LwwNyZALxkOvhvnZP24pMAZ03iukRMpCCq734PYwQJ9pmDjhfsJfWramaDE137yVcdyJ5v3P9UGanru92c+xmq5xIo9aE= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=lnKop/iQ; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="lnKop/iQ" 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 327EE1476; Mon, 3 Aug 2026 06:46:20 -0700 (PDT) Received: from e122027.cambridge.arm.com (e122027.cambridge.arm.com [10.1.25.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B3CEB3F66F; Mon, 3 Aug 2026 06:46:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785764784; bh=eKE4/Sm5/GuxJ8UFVqD6W1rOa6RVJlIeYRdiWlAXcYM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lnKop/iQ1vBgwO3c98+NFveOLzdZl5BN79cNYbyzjdR0a5hDnfW+j44/XXRARHA1F MnJAghBGoIZx63J99eUKA+YLh71dsj20fxRkv5vZoZLEwwgzb52ROJTE9HtVnOdsYl 1YaophYOu1qIb8iM84RtUxb7aCN6sJywHCpAQ+fY= 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 v16 27/45] KVM: arm64: CCA: Allow populating initial contents Date: Mon, 3 Aug 2026 14:43:43 +0100 Message-ID: <20260803134403.80630-28-steven.price@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260803134403.80630-1-steven.price@arm.com> References: <20260803134403.80630-1-steven.price@arm.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The VMM needs to populate the realm with some data before starting (e.g. a kernel and initrd). This is measured by the RMM and used as part of the attestation later on. Signed-off-by: Steven Price --- Changes since v15: * Handle negative error codes Changes since v14: * Holding of locks slots_lock and config_lock have been moved up the callstack with lockdesp assertions placed in the lower functions. * Add overflow check into kvm_arm_rmi_populate(). Changes since v13: * Rename realm_create_protected_data_page() to realm_data_map_init(). Changes since v12: * The ioctl now updates the structure with the amount populated rather than returning this through the ioctl return code. * Use the new RMM v2.0 range based RMI calls. * Adapt to upstream changes in kvm_gmem_populate(). Changes since v11: * The multiplex CAP is gone and there's a new ioctl which makes use of the generic kvm_gmem_populate() functionality. Changes since v7: * Improve the error codes. * Other minor changes from review. Changes since v6: * Handle host potentially having a larger page size than the RMM granule. * Drop historic "par" (protected address range) from populate_par_region() - it doesn't exist within the current architecture. * Add a cond_resched() call in kvm_populate_realm(). Changes since v5: * Refactor to use PFNs rather than tracking struct page in realm_create_protected_data_page(). * Pull changes from a later patch (in the v5 series) for accessing pages from a guest memfd. * Do the populate in chunks to avoid holding locks for too long and triggering RCU stall warnings. --- arch/arm64/include/asm/kvm_rmi.h | 4 ++ arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/arm.c | 13 ++++ arch/arm64/kvm/rmi.c | 119 +++++++++++++++++++++++++++++++ 4 files changed, 137 insertions(+) diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_rmi.h index 90563183a717..03f8bd2d13a2 100644 --- a/arch/arm64/include/asm/kvm_rmi.h +++ b/arch/arm64/include/asm/kvm_rmi.h @@ -108,6 +108,10 @@ int kvm_rec_exit(struct kvm_vcpu *vcpu, int rec_run_status); int kvm_rec_handle_request(struct kvm_vcpu *vcpu); bool kvm_rec_handle_hvc(struct kvm_vcpu *vcpu, int *ret); +struct kvm_arm_rmi_populate; + +int kvm_arm_rmi_populate(struct kvm *kvm, + struct kvm_arm_rmi_populate *arg); void kvm_realm_unmap_range(struct kvm *kvm, unsigned long ipa, unsigned long size, diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 189e8ad78b22..83b95e836b4d 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -37,6 +37,7 @@ menuconfig KVM select SCHED_INFO select GUEST_PERF_EVENTS if PERF_EVENTS select KVM_GUEST_MEMFD + select HAVE_KVM_ARCH_GMEM_POPULATE select ARM_RMM help Support hosting virtualized guest machines. diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index b7c308817d45..f1b26b263bf0 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -2154,6 +2154,19 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg) return -EFAULT; return kvm_vm_ioctl_get_reg_writable_masks(kvm, &range); } + case KVM_ARM_RMI_POPULATE: { + struct kvm_arm_rmi_populate req; + int ret; + + if (!kvm_is_realm(kvm)) + return -ENXIO; + if (copy_from_user(&req, argp, sizeof(req))) + return -EFAULT; + ret = kvm_arm_rmi_populate(kvm, &req); + if (copy_to_user(argp, &req, sizeof(req))) + return -EFAULT; + return ret; + } default: return -EINVAL; } diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c index c8ec766d3dc0..d18c241f7eb2 100644 --- a/arch/arm64/kvm/rmi.c +++ b/arch/arm64/kvm/rmi.c @@ -609,6 +609,76 @@ void kvm_realm_unmap_range(struct kvm *kvm, unsigned long start, realm_unmap_private_range(kvm, start, end, may_block); } +static int realm_data_map_init(struct kvm *kvm, unsigned long ipa, + kvm_pfn_t dst_pfn, kvm_pfn_t src_pfn, + unsigned long flags) +{ + struct realm *realm = &kvm->arch.realm; + phys_addr_t rd = virt_to_phys(realm->rd); + phys_addr_t dst_phys, src_phys; + long ret; + + lockdep_assert_held(&kvm->slots_lock); + lockdep_assert_held(&kvm->arch.config_lock); + + dst_phys = __pfn_to_phys(dst_pfn); + src_phys = __pfn_to_phys(src_pfn); + + if (rmi_delegate_page(dst_phys)) + return -ENXIO; + +retry: + ret = rmi_rtt_data_map_init(rd, dst_phys, ipa, src_phys, flags); + if (ret >= 0 && RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) { + /* Create missing RTTs and retry */ + int level = RMI_RETURN_INDEX(ret); + + KVM_BUG_ON(level >= KVM_PGTABLE_LAST_LEVEL, kvm); + + ret = realm_create_rtt_levels(realm, ipa, level, + level + 1, NULL); + if (!ret) + goto retry; + } + + if (ret && WARN_ON(rmi_undelegate_page(dst_phys))) { + /* Leak the page if the undelegate fails */ + get_page(pfn_to_page(dst_pfn)); + } + + return ret <= 0 ? ret : -ENXIO; +} + +static int populate_region_cb(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, + struct page *src_page, void *opaque) +{ + unsigned long data_flags = *(unsigned long *)opaque; + phys_addr_t ipa = gfn_to_gpa(gfn); + + return realm_data_map_init(kvm, ipa, pfn, page_to_pfn(src_page), + data_flags); +} + +static long populate_region(struct kvm *kvm, + gfn_t base_gfn, + unsigned long pages, + u64 uaddr, + unsigned long data_flags) +{ + long ret = 0; + + lockdep_assert_held(&kvm->slots_lock); + lockdep_assert_held(&kvm->arch.config_lock); + + if (!uaddr) + return -EINVAL; + + ret = kvm_gmem_populate(kvm, base_gfn, u64_to_user_ptr(uaddr), pages, + false, populate_region_cb, &data_flags); + + return ret; +} + enum ripas_action { RIPAS_INIT, RIPAS_SET, @@ -727,6 +797,55 @@ static int realm_ensure_created(struct kvm *kvm) return realm_create_rd(kvm); } +int kvm_arm_rmi_populate(struct kvm *kvm, + struct kvm_arm_rmi_populate *args) +{ + unsigned long data_flags = 0; + unsigned long ipa_start = args->base; + unsigned long ipa_end = ipa_start + args->size; + long pages_populated; + int ret; + + if (args->reserved || + (args->flags & ~KVM_ARM_RMI_POPULATE_FLAGS_MEASURE) || + args->base + args->size < args->base || + !IS_ALIGNED(ipa_start, PAGE_SIZE) || + !IS_ALIGNED(ipa_end, PAGE_SIZE) || + !IS_ALIGNED(args->source_uaddr, PAGE_SIZE)) + return -EINVAL; + + if (args->flags & KVM_ARM_RMI_POPULATE_FLAGS_MEASURE) + data_flags |= RMI_MEASURE_CONTENT; + + mutex_lock(&kvm->slots_lock); + mutex_lock(&kvm->arch.config_lock); + + ret = realm_ensure_created(kvm); + if (ret) + goto out_unlock; + + if (args->size == 0) + goto out_unlock; + + pages_populated = populate_region(kvm, gpa_to_gfn(ipa_start), + args->size >> PAGE_SHIFT, + args->source_uaddr, data_flags); + + if (pages_populated < 0) { + ret = pages_populated; + goto out_unlock; + } + + args->size -= pages_populated << PAGE_SHIFT; + args->source_uaddr += pages_populated << PAGE_SHIFT; + args->base += pages_populated << PAGE_SHIFT; + +out_unlock: + mutex_unlock(&kvm->arch.config_lock); + mutex_unlock(&kvm->slots_lock); + return ret; +} + static int kvm_complete_ripas_change(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; -- 2.43.0