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 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 | 9 ++ arch/arm64/kvm/rmi.c | 175 +++++++++++++++++++++++++++++++ 4 files changed, 189 insertions(+) diff --git a/arch/arm64/include/asm/kvm_rmi.h b/arch/arm64/include/asm/kvm_rmi.h index 8a862fc1a99d..b5e36344975c 100644 --- a/arch/arm64/include/asm/kvm_rmi.h +++ b/arch/arm64/include/asm/kvm_rmi.h @@ -99,6 +99,10 @@ int kvm_rec_enter(struct kvm_vcpu *vcpu); int kvm_rec_pre_enter(struct kvm_vcpu *vcpu); int handle_rec_exit(struct kvm_vcpu *vcpu, int rec_run_status); +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 1cac6dfc0972..b495dfd3a8b4 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -39,6 +39,7 @@ menuconfig KVM select GUEST_PERF_EVENTS if PERF_EVENTS select KVM_GUEST_MEMFD select KVM_GENERIC_MEMORY_ATTRIBUTES + select HAVE_KVM_ARCH_GMEM_POPULATE help Support hosting virtualized guest machines. diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 7927181887cf..0a06ed9d1a64 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -2037,6 +2037,15 @@ 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; + + if (!kvm_is_realm(kvm)) + return -EPERM; + if (copy_from_user(&req, argp, sizeof(req))) + return -EFAULT; + return kvm_arm_rmi_populate(kvm, &req); + } default: return -EINVAL; } diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c index fe15b400091c..39577e956a59 100644 --- a/arch/arm64/kvm/rmi.c +++ b/arch/arm64/kvm/rmi.c @@ -558,6 +558,150 @@ void kvm_realm_unmap_range(struct kvm *kvm, unsigned long start, realm_unmap_private_range(kvm, start, end, may_block); } +static int realm_create_protected_data_granule(struct realm *realm, + unsigned long ipa, + phys_addr_t dst_phys, + phys_addr_t src_phys, + unsigned long flags) +{ + phys_addr_t rd = virt_to_phys(realm->rd); + int ret; + + if (rmi_granule_delegate(dst_phys)) + return -ENXIO; + + ret = rmi_data_create(rd, dst_phys, ipa, src_phys, flags); + if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) { + /* Create missing RTTs and retry */ + int level = RMI_RETURN_INDEX(ret); + + WARN_ON(level == RMM_RTT_MAX_LEVEL); + + ret = realm_create_rtt_levels(realm, ipa, level, + RMM_RTT_MAX_LEVEL, NULL); + if (ret) + return -EIO; + + ret = rmi_data_create(rd, dst_phys, ipa, src_phys, flags); + } + if (ret) + return -EIO; + + return 0; +} + +static int realm_create_protected_data_page(struct realm *realm, + unsigned long ipa, + kvm_pfn_t dst_pfn, + kvm_pfn_t src_pfn, + unsigned long flags) +{ + unsigned long rd = virt_to_phys(realm->rd); + phys_addr_t dst_phys, src_phys; + bool undelegate_failed = false; + int ret, offset; + + dst_phys = __pfn_to_phys(dst_pfn); + src_phys = __pfn_to_phys(src_pfn); + + for (offset = 0; offset < PAGE_SIZE; offset += RMM_PAGE_SIZE) { + ret = realm_create_protected_data_granule(realm, + ipa, + dst_phys, + src_phys, + flags); + if (ret) + goto err; + + ipa += RMM_PAGE_SIZE; + dst_phys += RMM_PAGE_SIZE; + src_phys += RMM_PAGE_SIZE; + } + + return 0; + +err: + if (ret == -EIO) { + /* current offset needs undelegating */ + if (WARN_ON(rmi_granule_undelegate(dst_phys))) + undelegate_failed = true; + } + while (offset > 0) { + ipa -= RMM_PAGE_SIZE; + offset -= RMM_PAGE_SIZE; + dst_phys -= RMM_PAGE_SIZE; + + rmi_data_destroy(rd, ipa, NULL, NULL); + + if (WARN_ON(rmi_granule_undelegate(dst_phys))) + undelegate_failed = true; + } + + if (undelegate_failed) { + /* + * A granule could not be undelegated, + * so the page has to be leaked + */ + get_page(pfn_to_page(dst_pfn)); + } + + return -ENXIO; +} + +static int populate_region_cb(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, + void __user *src, int order, void *opaque) +{ + struct realm *realm = &kvm->arch.realm; + unsigned long data_flags = *(unsigned long *)opaque; + phys_addr_t ipa = gfn_to_gpa(gfn); + int npages = (1 << order); + int i; + + for (i = 0; i < npages; i++) { + struct page *src_page; + int ret; + + ret = get_user_pages((unsigned long)src, 1, 0, &src_page); + if (ret < 0) + return ret; + if (ret != 1) + return -ENOMEM; + + ret = realm_create_protected_data_page(realm, ipa, pfn, + page_to_pfn(src_page), + data_flags); + + put_page(src_page); + + if (ret) + return ret; + + ipa += PAGE_SIZE; + pfn++; + src += PAGE_SIZE; + } + + return 0; +} + +static long populate_region(struct kvm *kvm, + gfn_t base_gfn, + unsigned long pages, + u64 uaddr, + unsigned long data_flags) +{ + long ret = 0; + + mutex_lock(&kvm->slots_lock); + mmap_read_lock(current->mm); + ret = kvm_gmem_populate(kvm, base_gfn, u64_to_user_ptr(uaddr), pages, + populate_region_cb, &data_flags); + mmap_read_unlock(current->mm); + mutex_unlock(&kvm->slots_lock); + + return ret; +} + enum ripas_action { RIPAS_INIT, RIPAS_SET, @@ -655,6 +799,37 @@ static int realm_ensure_created(struct kvm *kvm) return -ENXIO; } +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; + int ret; + + if (args->reserved || + (args->flags & ~KVM_ARM_RMI_POPULATE_FLAGS_MEASURE) || + !IS_ALIGNED(ipa_start, PAGE_SIZE) || + !IS_ALIGNED(ipa_end, PAGE_SIZE)) + return -EINVAL; + + ret = realm_ensure_created(kvm); + if (ret) + return ret; + + if (args->flags & KVM_ARM_RMI_POPULATE_FLAGS_MEASURE) + data_flags |= RMI_MEASURE_CONTENT; + + ret = populate_region(kvm, gpa_to_gfn(ipa_start), + args->size >> PAGE_SHIFT, + args->source_uaddr, args->flags); + + if (ret < 0) + return ret; + + return ret * PAGE_SIZE; +} + static void kvm_complete_ripas_change(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; -- 2.43.0