1 files changed, 487 insertions, 0 deletions

diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
new file mode 100644
index 000000000000..d7a0f69a9982
--- /dev/null
+++ b/arch/arm64/kvm/pkvm.c
@@ -0,0 +1,487 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 - Google LLC
+ * Author: Quentin Perret <qperret@google.com>
+ */
+
+#include <linux/init.h>
+#include <linux/interval_tree_generic.h>
+#include <linux/kmemleak.h>
+#include <linux/kvm_host.h>
+#include <asm/kvm_mmu.h>
+#include <linux/memblock.h>
+#include <linux/mutex.h>
+
+#include <asm/kvm_pkvm.h>
+
+#include "hyp_constants.h"
+
+DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
+
+static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory);
+static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr);
+
+phys_addr_t hyp_mem_base;
+phys_addr_t hyp_mem_size;
+
+static int __init register_memblock_regions(void)
+{
+	struct memblock_region *reg;
+
+	for_each_mem_region(reg) {
+		if (*hyp_memblock_nr_ptr >= HYP_MEMBLOCK_REGIONS)
+			return -ENOMEM;
+
+		hyp_memory[*hyp_memblock_nr_ptr] = *reg;
+		(*hyp_memblock_nr_ptr)++;
+	}
+
+	return 0;
+}
+
+void __init kvm_hyp_reserve(void)
+{
+	u64 hyp_mem_pages = 0;
+	int ret;
+
+	if (!is_hyp_mode_available() || is_kernel_in_hyp_mode())
+		return;
+
+	if (kvm_get_mode() != KVM_MODE_PROTECTED)
+		return;
+
+	ret = register_memblock_regions();
+	if (ret) {
+		*hyp_memblock_nr_ptr = 0;
+		kvm_err("Failed to register hyp memblocks: %d\n", ret);
+		return;
+	}
+
+	hyp_mem_pages += hyp_s1_pgtable_pages();
+	hyp_mem_pages += host_s2_pgtable_pages();
+	hyp_mem_pages += hyp_vm_table_pages();
+	hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE);
+	hyp_mem_pages += pkvm_selftest_pages();
+	hyp_mem_pages += hyp_ffa_proxy_pages();
+
+	/*
+	 * Try to allocate a PMD-aligned region to reduce TLB pressure once
+	 * this is unmapped from the host stage-2, and fallback to PAGE_SIZE.
+	 */
+	hyp_mem_size = hyp_mem_pages << PAGE_SHIFT;
+	hyp_mem_base = memblock_phys_alloc(ALIGN(hyp_mem_size, PMD_SIZE),
+					   PMD_SIZE);
+	if (!hyp_mem_base)
+		hyp_mem_base = memblock_phys_alloc(hyp_mem_size, PAGE_SIZE);
+	else
+		hyp_mem_size = ALIGN(hyp_mem_size, PMD_SIZE);
+
+	if (!hyp_mem_base) {
+		kvm_err("Failed to reserve hyp memory\n");
+		return;
+	}
+
+	kvm_info("Reserved %lld MiB at 0x%llx\n", hyp_mem_size >> 20,
+		 hyp_mem_base);
+}
+
+static void __pkvm_destroy_hyp_vm(struct kvm *kvm)
+{
+	if (pkvm_hyp_vm_is_created(kvm)) {
+		WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm,
+					  kvm->arch.pkvm.handle));
+	} else if (kvm->arch.pkvm.handle) {
+		/*
+		 * The VM could have been reserved but hyp initialization has
+		 * failed. Make sure to unreserve it.
+		 */
+		kvm_call_hyp_nvhe(__pkvm_unreserve_vm, kvm->arch.pkvm.handle);
+	}
+
+	kvm->arch.pkvm.handle = 0;
+	kvm->arch.pkvm.is_created = false;
+	free_hyp_memcache(&kvm->arch.pkvm.teardown_mc);
+	free_hyp_memcache(&kvm->arch.pkvm.stage2_teardown_mc);
+}
+
+static int __pkvm_create_hyp_vcpu(struct kvm_vcpu *vcpu)
+{
+	size_t hyp_vcpu_sz = PAGE_ALIGN(PKVM_HYP_VCPU_SIZE);
+	pkvm_handle_t handle = vcpu->kvm->arch.pkvm.handle;
+	void *hyp_vcpu;
+	int ret;
+
+	vcpu->arch.pkvm_memcache.flags |= HYP_MEMCACHE_ACCOUNT_STAGE2;
+
+	hyp_vcpu = alloc_pages_exact(hyp_vcpu_sz, GFP_KERNEL_ACCOUNT);
+	if (!hyp_vcpu)
+		return -ENOMEM;
+
+	ret = kvm_call_hyp_nvhe(__pkvm_init_vcpu, handle, vcpu, hyp_vcpu);
+	if (!ret)
+		vcpu_set_flag(vcpu, VCPU_PKVM_FINALIZED);
+	else
+		free_pages_exact(hyp_vcpu, hyp_vcpu_sz);
+
+	return ret;
+}
+
+/*
+ * Allocates and donates memory for hypervisor VM structs at EL2.
+ *
+ * Allocates space for the VM state, which includes the hyp vm as well as
+ * the hyp vcpus.
+ *
+ * Stores an opaque handler in the kvm struct for future reference.
+ *
+ * Return 0 on success, negative error code on failure.
+ */
+static int __pkvm_create_hyp_vm(struct kvm *kvm)
+{
+	size_t pgd_sz, hyp_vm_sz;
+	void *pgd, *hyp_vm;
+	int ret;
+
+	if (kvm->created_vcpus < 1)
+		return -EINVAL;
+
+	pgd_sz = kvm_pgtable_stage2_pgd_size(kvm->arch.mmu.vtcr);
+
+	/*
+	 * The PGD pages will be reclaimed using a hyp_memcache which implies
+	 * page granularity. So, use alloc_pages_exact() to get individual
+	 * refcounts.
+	 */
+	pgd = alloc_pages_exact(pgd_sz, GFP_KERNEL_ACCOUNT);
+	if (!pgd)
+		return -ENOMEM;
+
+	/* Allocate memory to donate to hyp for vm and vcpu pointers. */
+	hyp_vm_sz = PAGE_ALIGN(size_add(PKVM_HYP_VM_SIZE,
+					size_mul(sizeof(void *),
+						 kvm->created_vcpus)));
+	hyp_vm = alloc_pages_exact(hyp_vm_sz, GFP_KERNEL_ACCOUNT);
+	if (!hyp_vm) {
+		ret = -ENOMEM;
+		goto free_pgd;
+	}
+
+	/* Donate the VM memory to hyp and let hyp initialize it. */
+	ret = kvm_call_hyp_nvhe(__pkvm_init_vm, kvm, hyp_vm, pgd);
+	if (ret)
+		goto free_vm;
+
+	kvm->arch.pkvm.is_created = true;
+	kvm->arch.pkvm.stage2_teardown_mc.flags |= HYP_MEMCACHE_ACCOUNT_STAGE2;
+	kvm_account_pgtable_pages(pgd, pgd_sz / PAGE_SIZE);
+
+	return 0;
+free_vm:
+	free_pages_exact(hyp_vm, hyp_vm_sz);
+free_pgd:
+	free_pages_exact(pgd, pgd_sz);
+	return ret;
+}
+
+bool pkvm_hyp_vm_is_created(struct kvm *kvm)
+{
+	return READ_ONCE(kvm->arch.pkvm.is_created);
+}
+
+int pkvm_create_hyp_vm(struct kvm *kvm)
+{
+	int ret = 0;
+
+	mutex_lock(&kvm->arch.config_lock);
+	if (!pkvm_hyp_vm_is_created(kvm))
+		ret = __pkvm_create_hyp_vm(kvm);
+	mutex_unlock(&kvm->arch.config_lock);
+
+	return ret;
+}
+
+int pkvm_create_hyp_vcpu(struct kvm_vcpu *vcpu)
+{
+	int ret = 0;
+
+	mutex_lock(&vcpu->kvm->arch.config_lock);
+	if (!vcpu_get_flag(vcpu, VCPU_PKVM_FINALIZED))
+		ret = __pkvm_create_hyp_vcpu(vcpu);
+	mutex_unlock(&vcpu->kvm->arch.config_lock);
+
+	return ret;
+}
+
+void pkvm_destroy_hyp_vm(struct kvm *kvm)
+{
+	mutex_lock(&kvm->arch.config_lock);
+	__pkvm_destroy_hyp_vm(kvm);
+	mutex_unlock(&kvm->arch.config_lock);
+}
+
+int pkvm_init_host_vm(struct kvm *kvm)
+{
+	int ret;
+
+	if (pkvm_hyp_vm_is_created(kvm))
+		return -EINVAL;
+
+	/* VM is already reserved, no need to proceed. */
+	if (kvm->arch.pkvm.handle)
+		return 0;
+
+	/* Reserve the VM in hyp and obtain a hyp handle for the VM. */
+	ret = kvm_call_hyp_nvhe(__pkvm_reserve_vm);
+	if (ret < 0)
+		return ret;
+
+	kvm->arch.pkvm.handle = ret;
+
+	return 0;
+}
+
+static void __init _kvm_host_prot_finalize(void *arg)
+{
+	int *err = arg;
+
+	if (WARN_ON(kvm_call_hyp_nvhe(__pkvm_prot_finalize)))
+		WRITE_ONCE(*err, -EINVAL);
+}
+
+static int __init pkvm_drop_host_privileges(void)
+{
+	int ret = 0;
+
+	/*
+	 * Flip the static key upfront as that may no longer be possible
+	 * once the host stage 2 is installed.
+	 */
+	static_branch_enable(&kvm_protected_mode_initialized);
+	on_each_cpu(_kvm_host_prot_finalize, &ret, 1);
+	return ret;
+}
+
+static int __init finalize_pkvm(void)
+{
+	int ret;
+
+	if (!is_protected_kvm_enabled() || !is_kvm_arm_initialised())
+		return 0;
+
+	/*
+	 * Exclude HYP sections from kmemleak so that they don't get peeked
+	 * at, which would end badly once inaccessible.
+	 */
+	kmemleak_free_part(__hyp_bss_start, __hyp_bss_end - __hyp_bss_start);
+	kmemleak_free_part(__hyp_data_start, __hyp_data_end - __hyp_data_start);
+	kmemleak_free_part(__hyp_rodata_start, __hyp_rodata_end - __hyp_rodata_start);
+	kmemleak_free_part_phys(hyp_mem_base, hyp_mem_size);
+
+	ret = pkvm_drop_host_privileges();
+	if (ret)
+		pr_err("Failed to finalize Hyp protection: %d\n", ret);
+
+	return ret;
+}
+device_initcall_sync(finalize_pkvm);
+
+static u64 __pkvm_mapping_start(struct pkvm_mapping *m)
+{
+	return m->gfn * PAGE_SIZE;
+}
+
+static u64 __pkvm_mapping_end(struct pkvm_mapping *m)
+{
+	return (m->gfn + m->nr_pages) * PAGE_SIZE - 1;
+}
+
+INTERVAL_TREE_DEFINE(struct pkvm_mapping, node, u64, __subtree_last,
+		     __pkvm_mapping_start, __pkvm_mapping_end, static,
+		     pkvm_mapping);
+
+/*
+ * __tmp is updated to iter_first(pkvm_mappings) *before* entering the body of the loop to allow
+ * freeing of __map inline.
+ */
+#define for_each_mapping_in_range_safe(__pgt, __start, __end, __map)				\
+	for (struct pkvm_mapping *__tmp = pkvm_mapping_iter_first(&(__pgt)->pkvm_mappings,	\
+								  __start, __end - 1);		\
+	     __tmp && ({									\
+				__map = __tmp;							\
+				__tmp = pkvm_mapping_iter_next(__map, __start, __end - 1);	\
+				true;								\
+		       });									\
+	    )
+
+int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
+			     struct kvm_pgtable_mm_ops *mm_ops)
+{
+	pgt->pkvm_mappings	= RB_ROOT_CACHED;
+	pgt->mmu		= mmu;
+
+	return 0;
+}
+
+static int __pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 start, u64 end)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	pkvm_handle_t handle = kvm->arch.pkvm.handle;
+	struct pkvm_mapping *mapping;
+	int ret;
+
+	if (!handle)
+		return 0;
+
+	for_each_mapping_in_range_safe(pgt, start, end, mapping) {
+		ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn,
+					mapping->nr_pages);
+		if (WARN_ON(ret))
+			return ret;
+		pkvm_mapping_remove(mapping, &pgt->pkvm_mappings);
+		kfree(mapping);
+	}
+
+	return 0;
+}
+
+void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt,
+					u64 addr, u64 size)
+{
+	__pkvm_pgtable_stage2_unmap(pgt, addr, addr + size);
+}
+
+void pkvm_pgtable_stage2_destroy_pgd(struct kvm_pgtable *pgt)
+{
+	/* Expected to be called after all pKVM mappings have been released. */
+	WARN_ON_ONCE(!RB_EMPTY_ROOT(&pgt->pkvm_mappings.rb_root));
+}
+
+int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
+			   u64 phys, enum kvm_pgtable_prot prot,
+			   void *mc, enum kvm_pgtable_walk_flags flags)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	struct pkvm_mapping *mapping = NULL;
+	struct kvm_hyp_memcache *cache = mc;
+	u64 gfn = addr >> PAGE_SHIFT;
+	u64 pfn = phys >> PAGE_SHIFT;
+	int ret;
+
+	if (size != PAGE_SIZE && size != PMD_SIZE)
+		return -EINVAL;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+
+	/*
+	 * Calling stage2_map() on top of existing mappings is either happening because of a race
+	 * with another vCPU, or because we're changing between page and block mappings. As per
+	 * user_mem_abort(), same-size permission faults are handled in the relax_perms() path.
+	 */
+	mapping = pkvm_mapping_iter_first(&pgt->pkvm_mappings, addr, addr + size - 1);
+	if (mapping) {
+		if (size == (mapping->nr_pages * PAGE_SIZE))
+			return -EAGAIN;
+
+		/* Remove _any_ pkvm_mapping overlapping with the range, bigger or smaller. */
+		ret = __pkvm_pgtable_stage2_unmap(pgt, addr, addr + size);
+		if (ret)
+			return ret;
+		mapping = NULL;
+	}
+
+	ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, size / PAGE_SIZE, prot);
+	if (WARN_ON(ret))
+		return ret;
+
+	swap(mapping, cache->mapping);
+	mapping->gfn = gfn;
+	mapping->pfn = pfn;
+	mapping->nr_pages = size / PAGE_SIZE;
+	pkvm_mapping_insert(mapping, &pgt->pkvm_mappings);
+
+	return ret;
+}
+
+int pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
+{
+	lockdep_assert_held_write(&kvm_s2_mmu_to_kvm(pgt->mmu)->mmu_lock);
+
+	return __pkvm_pgtable_stage2_unmap(pgt, addr, addr + size);
+}
+
+int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	pkvm_handle_t handle = kvm->arch.pkvm.handle;
+	struct pkvm_mapping *mapping;
+	int ret = 0;
+
+	lockdep_assert_held(&kvm->mmu_lock);
+	for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) {
+		ret = kvm_call_hyp_nvhe(__pkvm_host_wrprotect_guest, handle, mapping->gfn,
+					mapping->nr_pages);
+		if (WARN_ON(ret))
+			break;
+	}
+
+	return ret;
+}
+
+int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	struct pkvm_mapping *mapping;
+
+	lockdep_assert_held(&kvm->mmu_lock);
+	for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
+		__clean_dcache_guest_page(pfn_to_kaddr(mapping->pfn),
+					  PAGE_SIZE * mapping->nr_pages);
+
+	return 0;
+}
+
+bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64 size, bool mkold)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	pkvm_handle_t handle = kvm->arch.pkvm.handle;
+	struct pkvm_mapping *mapping;
+	bool young = false;
+
+	lockdep_assert_held(&kvm->mmu_lock);
+	for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
+		young |= kvm_call_hyp_nvhe(__pkvm_host_test_clear_young_guest, handle, mapping->gfn,
+					   mapping->nr_pages, mkold);
+
+	return young;
+}
+
+int pkvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, enum kvm_pgtable_prot prot,
+				    enum kvm_pgtable_walk_flags flags)
+{
+	return kvm_call_hyp_nvhe(__pkvm_host_relax_perms_guest, addr >> PAGE_SHIFT, prot);
+}
+
+void pkvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
+				 enum kvm_pgtable_walk_flags flags)
+{
+	WARN_ON(kvm_call_hyp_nvhe(__pkvm_host_mkyoung_guest, addr >> PAGE_SHIFT));
+}
+
+void pkvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level)
+{
+	WARN_ON_ONCE(1);
+}
+
+kvm_pte_t *pkvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, u64 phys, s8 level,
+					enum kvm_pgtable_prot prot, void *mc, bool force_pte)
+{
+	WARN_ON_ONCE(1);
+	return NULL;
+}
+
+int pkvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
+			      struct kvm_mmu_memory_cache *mc)
+{
+	WARN_ON_ONCE(1);
+	return -EINVAL;
+}