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[88.115.161.74]) by smtp.gmail.com with ESMTPSA id k16-20020a2ea270000000b002947028ae7csm1818432ljm.72.2023.03.06.09.34.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Mar 2023 09:34:40 -0800 (PST) Date: Mon, 6 Mar 2023 19:34:39 +0200 From: Zhi Wang To: Steven Price Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, 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 Subject: Re: [RFC PATCH 16/28] arm64: RME: Allow populating initial contents Message-ID: <20230306193439.000048f2@gmail.com> In-Reply-To: <20230127112932.38045-17-steven.price@arm.com> References: <20230127112248.136810-1-suzuki.poulose@arm.com> <20230127112932.38045-1-steven.price@arm.com> <20230127112932.38045-17-steven.price@arm.com> X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 27 Jan 2023 11:29:20 +0000 Steven Price wrote: > 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 > --- > arch/arm64/kvm/rme.c | 366 +++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 366 insertions(+) > > diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c > index 16e0bfea98b1..3405b43e1421 100644 > --- a/arch/arm64/kvm/rme.c > +++ b/arch/arm64/kvm/rme.c > @@ -4,6 +4,7 @@ > */ > > #include > +#include > > #include > #include > @@ -426,6 +427,359 @@ void kvm_realm_unmap_range(struct kvm *kvm, unsigned long ipa, u64 size) > } > } > > +static int realm_create_protected_data_page(struct realm *realm, > + unsigned long ipa, > + struct page *dst_page, > + struct page *tmp_page) > +{ > + phys_addr_t dst_phys, tmp_phys; > + int ret; > + > + copy_page(page_address(tmp_page), page_address(dst_page)); > + > + dst_phys = page_to_phys(dst_page); > + tmp_phys = page_to_phys(tmp_page); > + > + if (rmi_granule_delegate(dst_phys)) > + return -ENXIO; > + > + ret = rmi_data_create(dst_phys, virt_to_phys(realm->rd), ipa, tmp_phys, > + RMI_MEASURE_CONTENT); > + > + if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) { > + /* Create missing RTTs and retry */ > + int level = RMI_RETURN_INDEX(ret); > + > + ret = realm_create_rtt_levels(realm, ipa, level, > + RME_RTT_MAX_LEVEL, NULL); > + if (ret) > + goto err; > + > + ret = rmi_data_create(dst_phys, virt_to_phys(realm->rd), ipa, > + tmp_phys, RMI_MEASURE_CONTENT); > + } > + > + if (ret) > + goto err; > + > + return 0; > + > +err: > + if (WARN_ON(rmi_granule_undelegate(dst_phys))) { > + /* Page can't be returned to NS world so is lost */ > + get_page(dst_page); > + } > + return -ENXIO; > +} > + > +static int fold_rtt(phys_addr_t rd, unsigned long addr, int level, > + struct realm *realm) > +{ > + struct rtt_entry rtt; > + phys_addr_t rtt_addr; > + > + if (rmi_rtt_read_entry(rd, addr, level, &rtt)) > + return -ENXIO; > + > + if (rtt.state != RMI_TABLE) > + return -EINVAL; > + > + rtt_addr = rmi_rtt_get_phys(&rtt); > + if (rmi_rtt_fold(rtt_addr, rd, addr, level + 1)) > + return -ENXIO; > + > + free_delegated_page(realm, rtt_addr); > + > + return 0; > +} > + > +int realm_map_protected(struct realm *realm, > + unsigned long hva, > + unsigned long base_ipa, > + struct page *dst_page, > + unsigned long map_size, > + struct kvm_mmu_memory_cache *memcache) > +{ > + phys_addr_t dst_phys = page_to_phys(dst_page); > + phys_addr_t rd = virt_to_phys(realm->rd); > + unsigned long phys = dst_phys; > + unsigned long ipa = base_ipa; > + unsigned long size; > + int map_level; > + int ret = 0; > + > + if (WARN_ON(!IS_ALIGNED(ipa, map_size))) > + return -EINVAL; > + > + switch (map_size) { > + case PAGE_SIZE: > + map_level = 3; > + break; > + case RME_L2_BLOCK_SIZE: > + map_level = 2; > + break; > + default: > + return -EINVAL; > + } > + > + if (map_level < RME_RTT_MAX_LEVEL) { > + /* > + * A temporary RTT is needed during the map, precreate it, > + * however if there is an error (e.g. missing parent tables) > + * this will be handled below. > + */ > + realm_create_rtt_levels(realm, ipa, map_level, > + RME_RTT_MAX_LEVEL, memcache); > + } > + > + for (size = 0; size < map_size; size += PAGE_SIZE) { > + if (rmi_granule_delegate(phys)) { > + struct rtt_entry rtt; > + > + /* > + * It's possible we raced with another VCPU on the same > + * fault. If the entry exists and matches then exit > + * early and assume the other VCPU will handle the > + * mapping. > + */ > + if (rmi_rtt_read_entry(rd, ipa, RME_RTT_MAX_LEVEL, &rtt)) > + goto err; > + > + // FIXME: For a block mapping this could race at level > + // 2 or 3... > + if (WARN_ON((rtt.walk_level != RME_RTT_MAX_LEVEL || > + rtt.state != RMI_ASSIGNED || > + rtt.desc != phys))) { > + goto err; > + } > + > + return 0; > + } > + > + ret = rmi_data_create_unknown(phys, rd, ipa); > + > + if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) { > + /* Create missing RTTs and retry */ > + int level = RMI_RETURN_INDEX(ret); > + > + ret = realm_create_rtt_levels(realm, ipa, level, > + RME_RTT_MAX_LEVEL, > + memcache); > + WARN_ON(ret); > + if (ret) > + goto err_undelegate; > + > + ret = rmi_data_create_unknown(phys, rd, ipa); > + } > + WARN_ON(ret); > + > + if (ret) > + goto err_undelegate; > + > + phys += PAGE_SIZE; > + ipa += PAGE_SIZE; > + } > + > + if (map_size == RME_L2_BLOCK_SIZE) > + ret = fold_rtt(rd, base_ipa, map_level, realm); > + if (WARN_ON(ret)) > + goto err; > + > + return 0; > + > +err_undelegate: > + if (WARN_ON(rmi_granule_undelegate(phys))) { > + /* Page can't be returned to NS world so is lost */ > + get_page(phys_to_page(phys)); > + } > +err: > + while (size > 0) { > + phys -= PAGE_SIZE; > + size -= PAGE_SIZE; > + ipa -= PAGE_SIZE; > + > + rmi_data_destroy(rd, ipa); > + > + if (WARN_ON(rmi_granule_undelegate(phys))) { > + /* Page can't be returned to NS world so is lost */ > + get_page(phys_to_page(phys)); > + } > + } > + return -ENXIO; > +} > + There seems no caller to the function above. Better move it to the related patch. > +static int populate_par_region(struct kvm *kvm, > + phys_addr_t ipa_base, > + phys_addr_t ipa_end) > +{ > + struct realm *realm = &kvm->arch.realm; > + struct kvm_memory_slot *memslot; > + gfn_t base_gfn, end_gfn; > + int idx; > + phys_addr_t ipa; > + int ret = 0; > + struct page *tmp_page; > + phys_addr_t rd = virt_to_phys(realm->rd); > + > + base_gfn = gpa_to_gfn(ipa_base); > + end_gfn = gpa_to_gfn(ipa_end); > + > + idx = srcu_read_lock(&kvm->srcu); > + memslot = gfn_to_memslot(kvm, base_gfn); > + if (!memslot) { > + ret = -EFAULT; > + goto out; > + } > + > + /* We require the region to be contained within a single memslot */ > + if (memslot->base_gfn + memslot->npages < end_gfn) { > + ret = -EINVAL; > + goto out; > + } > + > + tmp_page = alloc_page(GFP_KERNEL); > + if (!tmp_page) { > + ret = -ENOMEM; > + goto out; > + } > + > + mmap_read_lock(current->mm); > + > + ipa = ipa_base; > + > + while (ipa < ipa_end) { > + struct vm_area_struct *vma; > + unsigned long map_size; > + unsigned int vma_shift; > + unsigned long offset; > + unsigned long hva; > + struct page *page; > + kvm_pfn_t pfn; > + int level; > + > + hva = gfn_to_hva_memslot(memslot, gpa_to_gfn(ipa)); > + vma = vma_lookup(current->mm, hva); > + if (!vma) { > + ret = -EFAULT; > + break; > + } > + > + if (is_vm_hugetlb_page(vma)) > + vma_shift = huge_page_shift(hstate_vma(vma)); > + else > + vma_shift = PAGE_SHIFT; > + > + map_size = 1 << vma_shift; > + > + /* > + * FIXME: This causes over mapping, but there's no good > + * solution here with the ABI as it stands > + */ > + ipa = ALIGN_DOWN(ipa, map_size); > + > + switch (map_size) { > + case RME_L2_BLOCK_SIZE: > + level = 2; > + break; > + case PAGE_SIZE: > + level = 3; > + break; > + default: > + WARN_ONCE(1, "Unsupport vma_shift %d", vma_shift); > + ret = -EFAULT; > + break; > + } > + > + pfn = gfn_to_pfn_memslot(memslot, gpa_to_gfn(ipa)); > + > + if (is_error_pfn(pfn)) { > + ret = -EFAULT; > + break; > + } > + > + ret = rmi_rtt_init_ripas(rd, ipa, level); > + if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) { > + ret = realm_create_rtt_levels(realm, ipa, > + RMI_RETURN_INDEX(ret), > + level, NULL); > + if (ret) > + break; > + ret = rmi_rtt_init_ripas(rd, ipa, level); > + if (ret) { > + ret = -ENXIO; > + break; > + } > + } > + > + if (level < RME_RTT_MAX_LEVEL) { > + /* > + * A temporary RTT is needed during the map, precreate > + * it, however if there is an error (e.g. missing > + * parent tables) this will be handled in the > + * realm_create_protected_data_page() call. > + */ > + realm_create_rtt_levels(realm, ipa, level, > + RME_RTT_MAX_LEVEL, NULL); > + } > + > + page = pfn_to_page(pfn); > + > + for (offset = 0; offset < map_size && !ret; > + offset += PAGE_SIZE, page++) { > + phys_addr_t page_ipa = ipa + offset; > + > + ret = realm_create_protected_data_page(realm, page_ipa, > + page, tmp_page); > + } > + if (ret) > + goto err_release_pfn; > + > + if (level == 2) { > + ret = fold_rtt(rd, ipa, level, realm); > + if (ret) > + goto err_release_pfn; > + } > + > + ipa += map_size; > + kvm_set_pfn_accessed(pfn); > + kvm_set_pfn_dirty(pfn); kvm_release_pfn_dirty() has already called kvm_set_pfn_{accessed, dirty}(). > + kvm_release_pfn_dirty(pfn); > +err_release_pfn: > + if (ret) { > + kvm_release_pfn_clean(pfn); > + break; > + } > + } > + > + mmap_read_unlock(current->mm); > + __free_page(tmp_page); > + > +out: > + srcu_read_unlock(&kvm->srcu, idx); > + return ret; > +} > + > +static int kvm_populate_realm(struct kvm *kvm, > + struct kvm_cap_arm_rme_populate_realm_args *args) > +{ > + phys_addr_t ipa_base, ipa_end; > + Check kvm_is_realm(kvm) here or in the kvm_realm_enable_cap(). > + if (kvm_realm_state(kvm) != REALM_STATE_NEW) > + return -EBUSY; Maybe -EINVAL? The realm hasn't been created (RMI_REALM_CREATE is not called yet). The userspace shouldn't reach this path. > + > + if (!IS_ALIGNED(args->populate_ipa_base, PAGE_SIZE) || > + !IS_ALIGNED(args->populate_ipa_size, PAGE_SIZE)) > + return -EINVAL; > + > + ipa_base = args->populate_ipa_base; > + ipa_end = ipa_base + args->populate_ipa_size; > + > + if (ipa_end < ipa_base) > + return -EINVAL; > + > + return populate_par_region(kvm, ipa_base, ipa_end); > +} > + > static int set_ipa_state(struct kvm_vcpu *vcpu, > unsigned long ipa, > unsigned long end, > @@ -748,6 +1102,18 @@ int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap) > r = kvm_init_ipa_range_realm(kvm, &args); > break; > } > + case KVM_CAP_ARM_RME_POPULATE_REALM: { > + struct kvm_cap_arm_rme_populate_realm_args args; > + void __user *argp = u64_to_user_ptr(cap->args[1]); > + > + if (copy_from_user(&args, argp, sizeof(args))) { > + r = -EFAULT; > + break; > + } > + > + r = kvm_populate_realm(kvm, &args); > + break; > + } > default: > r = -EINVAL; > break;