[PATCH v16 25/45] KVM: arm64: CCA: Create the realm descriptor

[Steven Price <steven.price@arm.com>]

Creating a realm involves first creating a realm descriptor (RD). This
involves passing the configuration information to the RMM. Do this as
part of realm_ensure_created() so that the realm is created when it is
first needed. The call to realm_ensure_created() will be added in a
later patch.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v15:
 * The page for realm parameters is now only temporarily allocated in
   realm_create_rd().
 * Deal with negative error codes.
Changes since v14:
 * Explicitly set hash_algo = RMI_HASH_SHA_256 (which is the default).
 * Support SRO flow during realm creation.
Changes since v13:
 * The RMM no longer uses AUX granules, so no need to ask it how many it
   needs.
 * Adapted to other changes.
Changes since v12:
 * Since RMM page size is now equal to the host's page size various
   calculations are simplified.
 * Switch to using range based APIs to delegate/undelegate.
 * VMID handling is now handled entirely by the RMM.
---
 arch/arm64/kvm/rmi.c | 95 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)

diff --git a/arch/arm64/kvm/rmi.c b/arch/arm64/kvm/rmi.c
index a7202054c8e6..31eedf78a752 100644
--- a/arch/arm64/kvm/rmi.c
+++ b/arch/arm64/kvm/rmi.c
@@ -462,6 +462,83 @@ static void realm_unmap_shared_range(struct kvm *kvm,
 			     start, end);
 }
 
+static int realm_create_rd(struct kvm *kvm)
+{
+	struct realm *realm = &kvm->arch.realm;
+	struct realm_params *params __free(free_page) = NULL;
+	void *rd = NULL;
+	phys_addr_t rd_phys, params_phys, top_delegated;
+	size_t pgd_size = kvm_pgtable_stage2_pgd_size(kvm->arch.mmu.vtcr);
+	long rmi_ret;
+	int r;
+
+	realm->ia_bits = VTCR_EL2_IPA(kvm->arch.mmu.vtcr);
+
+	if (WARN_ON(realm->rd))
+		return -EEXIST;
+
+	params = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
+	if (!params)
+		return -ENOMEM;
+
+	rd = (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
+	if (!rd)
+		return -ENOMEM;
+
+	rd_phys = virt_to_phys(rd);
+	if (rmi_delegate_page(rd_phys)) {
+		r = -ENXIO;
+		goto free_rd;
+	}
+
+	if (rmi_delegate_range(kvm->arch.mmu.pgd_phys, pgd_size,
+			       &top_delegated)) {
+		r = -ENXIO;
+		goto out_undelegate_tables;
+	}
+
+	params->s2sz = VTCR_EL2_IPA(kvm->arch.mmu.vtcr);
+	params->rtt_level_start = get_start_level(realm);
+	params->rtt_num_start = pgd_size / PAGE_SIZE;
+	params->rtt_base = kvm->arch.mmu.pgd_phys;
+	params->hash_algo = RMI_HASH_SHA_256;
+
+	if (kvm->arch.arm_pmu) {
+		params->pmu_num_ctrs = kvm->arch.nr_pmu_counters;
+		params->flags0 |= RMI_REALM_PARAM_FLAG_PMU;
+	}
+
+	if (kvm_lpa2_is_enabled())
+		params->flags0 |= RMI_REALM_PARAM_FLAG_LPA2;
+
+	params_phys = virt_to_phys(params);
+
+	rmi_ret = rmi_realm_create(rd_phys, params_phys, realm->sro);
+	if (rmi_ret) {
+		r = rmi_ret < 0 ? rmi_ret : -ENXIO;
+		goto out_undelegate_tables;
+	}
+
+	realm->rd = rd;
+	kvm_set_realm_state(kvm, REALM_STATE_NEW);
+
+	return 0;
+
+out_undelegate_tables:
+	if (WARN_ON(rmi_undelegate_range(kvm->arch.mmu.pgd_phys,
+					 top_delegated - kvm->arch.mmu.pgd_phys))) {
+		/* Leak the pages if they cannot be returned */
+		kvm->arch.mmu.pgt = NULL;
+	}
+	if (WARN_ON(rmi_undelegate_page(rd_phys))) {
+		/* Leak the page if it isn't returned */
+		return r;
+	}
+free_rd:
+	free_page((unsigned long)rd);
+	return r;
+}
+
 static void realm_unmap_private_range(struct kvm *kvm,
 				      unsigned long start,
 				      unsigned long end,
@@ -632,6 +709,24 @@ static int realm_set_ipa_state(struct kvm_vcpu *vcpu,
 	return ret;
 }
 
+static int __maybe_unused realm_ensure_created(struct kvm *kvm)
+{
+	lockdep_assert_held(&kvm->arch.config_lock);
+
+	switch (kvm_realm_state(kvm)) {
+	case REALM_STATE_NONE:
+		break;
+	case REALM_STATE_NEW:
+		return 0;
+	case REALM_STATE_DEAD:
+		return -ENXIO;
+	default:
+		return -EBUSY;
+	}
+
+	return realm_create_rd(kvm);
+}
+
 static int kvm_complete_ripas_change(struct kvm_vcpu *vcpu)
 {
 	struct kvm *kvm = vcpu->kvm;
-- 
2.43.0