1 files changed, 436 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 85d3b7ae720f..a06ece14a6d8 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -7,8 +7,17 @@
 #include <linux/kvm_host.h>
 #include <linux/mm.h>
 #include <nvhe/fixed_config.h>
+#include <nvhe/mem_protect.h>
+#include <nvhe/memory.h>
+#include <nvhe/pkvm.h>
 #include <nvhe/trap_handler.h>
 
+/* Used by icache_is_vpipt(). */
+unsigned long __icache_flags;
+
+/* Used by kvm_get_vttbr(). */
+unsigned int kvm_arm_vmid_bits;
+
 /*
  * Set trap register values based on features in ID_AA64PFR0.
  */
@@ -183,3 +192,430 @@ void __pkvm_vcpu_init_traps(struct kvm_vcpu *vcpu)
 	pvm_init_traps_aa64mmfr0(vcpu);
 	pvm_init_traps_aa64mmfr1(vcpu);
 }
+
+/*
+ * Start the VM table handle at the offset defined instead of at 0.
+ * Mainly for sanity checking and debugging.
+ */
+#define HANDLE_OFFSET 0x1000
+
+static unsigned int vm_handle_to_idx(pkvm_handle_t handle)
+{
+	return handle - HANDLE_OFFSET;
+}
+
+static pkvm_handle_t idx_to_vm_handle(unsigned int idx)
+{
+	return idx + HANDLE_OFFSET;
+}
+
+/*
+ * Spinlock for protecting state related to the VM table. Protects writes
+ * to 'vm_table' and 'nr_table_entries' as well as reads and writes to
+ * 'last_hyp_vcpu_lookup'.
+ */
+static DEFINE_HYP_SPINLOCK(vm_table_lock);
+
+/*
+ * The table of VM entries for protected VMs in hyp.
+ * Allocated at hyp initialization and setup.
+ */
+static struct pkvm_hyp_vm **vm_table;
+
+void pkvm_hyp_vm_table_init(void *tbl)
+{
+	WARN_ON(vm_table);
+	vm_table = tbl;
+}
+
+/*
+ * Return the hyp vm structure corresponding to the handle.
+ */
+static struct pkvm_hyp_vm *get_vm_by_handle(pkvm_handle_t handle)
+{
+	unsigned int idx = vm_handle_to_idx(handle);
+
+	if (unlikely(idx >= KVM_MAX_PVMS))
+		return NULL;
+
+	return vm_table[idx];
+}
+
+struct pkvm_hyp_vcpu *pkvm_load_hyp_vcpu(pkvm_handle_t handle,
+					 unsigned int vcpu_idx)
+{
+	struct pkvm_hyp_vcpu *hyp_vcpu = NULL;
+	struct pkvm_hyp_vm *hyp_vm;
+
+	hyp_spin_lock(&vm_table_lock);
+	hyp_vm = get_vm_by_handle(handle);
+	if (!hyp_vm || hyp_vm->nr_vcpus <= vcpu_idx)
+		goto unlock;
+
+	hyp_vcpu = hyp_vm->vcpus[vcpu_idx];
+	hyp_page_ref_inc(hyp_virt_to_page(hyp_vm));
+unlock:
+	hyp_spin_unlock(&vm_table_lock);
+	return hyp_vcpu;
+}
+
+void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
+{
+	struct pkvm_hyp_vm *hyp_vm = pkvm_hyp_vcpu_to_hyp_vm(hyp_vcpu);
+
+	hyp_spin_lock(&vm_table_lock);
+	hyp_page_ref_dec(hyp_virt_to_page(hyp_vm));
+	hyp_spin_unlock(&vm_table_lock);
+}
+
+static void unpin_host_vcpu(struct kvm_vcpu *host_vcpu)
+{
+	if (host_vcpu)
+		hyp_unpin_shared_mem(host_vcpu, host_vcpu + 1);
+}
+
+static void unpin_host_vcpus(struct pkvm_hyp_vcpu *hyp_vcpus[],
+			     unsigned int nr_vcpus)
+{
+	int i;
+
+	for (i = 0; i < nr_vcpus; i++)
+		unpin_host_vcpu(hyp_vcpus[i]->host_vcpu);
+}
+
+static void init_pkvm_hyp_vm(struct kvm *host_kvm, struct pkvm_hyp_vm *hyp_vm,
+			     unsigned int nr_vcpus)
+{
+	hyp_vm->host_kvm = host_kvm;
+	hyp_vm->kvm.created_vcpus = nr_vcpus;
+	hyp_vm->kvm.arch.vtcr = host_mmu.arch.vtcr;
+}
+
+static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu,
+			      struct pkvm_hyp_vm *hyp_vm,
+			      struct kvm_vcpu *host_vcpu,
+			      unsigned int vcpu_idx)
+{
+	int ret = 0;
+
+	if (hyp_pin_shared_mem(host_vcpu, host_vcpu + 1))
+		return -EBUSY;
+
+	if (host_vcpu->vcpu_idx != vcpu_idx) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	hyp_vcpu->host_vcpu = host_vcpu;
+
+	hyp_vcpu->vcpu.kvm = &hyp_vm->kvm;
+	hyp_vcpu->vcpu.vcpu_id = READ_ONCE(host_vcpu->vcpu_id);
+	hyp_vcpu->vcpu.vcpu_idx = vcpu_idx;
+
+	hyp_vcpu->vcpu.arch.hw_mmu = &hyp_vm->kvm.arch.mmu;
+	hyp_vcpu->vcpu.arch.cflags = READ_ONCE(host_vcpu->arch.cflags);
+done:
+	if (ret)
+		unpin_host_vcpu(host_vcpu);
+	return ret;
+}
+
+static int find_free_vm_table_entry(struct kvm *host_kvm)
+{
+	int i;
+
+	for (i = 0; i < KVM_MAX_PVMS; ++i) {
+		if (!vm_table[i])
+			return i;
+	}
+
+	return -ENOMEM;
+}
+
+/*
+ * Allocate a VM table entry and insert a pointer to the new vm.
+ *
+ * Return a unique handle to the protected VM on success,
+ * negative error code on failure.
+ */
+static pkvm_handle_t insert_vm_table_entry(struct kvm *host_kvm,
+					   struct pkvm_hyp_vm *hyp_vm)
+{
+	struct kvm_s2_mmu *mmu = &hyp_vm->kvm.arch.mmu;
+	int idx;
+
+	hyp_assert_lock_held(&vm_table_lock);
+
+	/*
+	 * Initializing protected state might have failed, yet a malicious
+	 * host could trigger this function. Thus, ensure that 'vm_table'
+	 * exists.
+	 */
+	if (unlikely(!vm_table))
+		return -EINVAL;
+
+	idx = find_free_vm_table_entry(host_kvm);
+	if (idx < 0)
+		return idx;
+
+	hyp_vm->kvm.arch.pkvm.handle = idx_to_vm_handle(idx);
+
+	/* VMID 0 is reserved for the host */
+	atomic64_set(&mmu->vmid.id, idx + 1);
+
+	mmu->arch = &hyp_vm->kvm.arch;
+	mmu->pgt = &hyp_vm->pgt;
+
+	vm_table[idx] = hyp_vm;
+	return hyp_vm->kvm.arch.pkvm.handle;
+}
+
+/*
+ * Deallocate and remove the VM table entry corresponding to the handle.
+ */
+static void remove_vm_table_entry(pkvm_handle_t handle)
+{
+	hyp_assert_lock_held(&vm_table_lock);
+	vm_table[vm_handle_to_idx(handle)] = NULL;
+}
+
+static size_t pkvm_get_hyp_vm_size(unsigned int nr_vcpus)
+{
+	return size_add(sizeof(struct pkvm_hyp_vm),
+		size_mul(sizeof(struct pkvm_hyp_vcpu *), nr_vcpus));
+}
+
+static void *map_donated_memory_noclear(unsigned long host_va, size_t size)
+{
+	void *va = (void *)kern_hyp_va(host_va);
+
+	if (!PAGE_ALIGNED(va))
+		return NULL;
+
+	if (__pkvm_host_donate_hyp(hyp_virt_to_pfn(va),
+				   PAGE_ALIGN(size) >> PAGE_SHIFT))
+		return NULL;
+
+	return va;
+}
+
+static void *map_donated_memory(unsigned long host_va, size_t size)
+{
+	void *va = map_donated_memory_noclear(host_va, size);
+
+	if (va)
+		memset(va, 0, size);
+
+	return va;
+}
+
+static void __unmap_donated_memory(void *va, size_t size)
+{
+	WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(va),
+				       PAGE_ALIGN(size) >> PAGE_SHIFT));
+}
+
+static void unmap_donated_memory(void *va, size_t size)
+{
+	if (!va)
+		return;
+
+	memset(va, 0, size);
+	__unmap_donated_memory(va, size);
+}
+
+static void unmap_donated_memory_noclear(void *va, size_t size)
+{
+	if (!va)
+		return;
+
+	__unmap_donated_memory(va, size);
+}
+
+/*
+ * Initialize the hypervisor copy of the protected VM state using the
+ * memory donated by the host.
+ *
+ * Unmaps the donated memory from the host at stage 2.
+ *
+ * host_kvm: A pointer to the host's struct kvm.
+ * vm_hva: The host va of the area being donated for the VM state.
+ *	   Must be page aligned.
+ * pgd_hva: The host va of the area being donated for the stage-2 PGD for
+ *	    the VM. Must be page aligned. Its size is implied by the VM's
+ *	    VTCR.
+ *
+ * Return a unique handle to the protected VM on success,
+ * negative error code on failure.
+ */
+int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva,
+		   unsigned long pgd_hva)
+{
+	struct pkvm_hyp_vm *hyp_vm = NULL;
+	size_t vm_size, pgd_size;
+	unsigned int nr_vcpus;
+	void *pgd = NULL;
+	int ret;
+
+	ret = hyp_pin_shared_mem(host_kvm, host_kvm + 1);
+	if (ret)
+		return ret;
+
+	nr_vcpus = READ_ONCE(host_kvm->created_vcpus);
+	if (nr_vcpus < 1) {
+		ret = -EINVAL;
+		goto err_unpin_kvm;
+	}
+
+	vm_size = pkvm_get_hyp_vm_size(nr_vcpus);
+	pgd_size = kvm_pgtable_stage2_pgd_size(host_mmu.arch.vtcr);
+
+	ret = -ENOMEM;
+
+	hyp_vm = map_donated_memory(vm_hva, vm_size);
+	if (!hyp_vm)
+		goto err_remove_mappings;
+
+	pgd = map_donated_memory_noclear(pgd_hva, pgd_size);
+	if (!pgd)
+		goto err_remove_mappings;
+
+	init_pkvm_hyp_vm(host_kvm, hyp_vm, nr_vcpus);
+
+	hyp_spin_lock(&vm_table_lock);
+	ret = insert_vm_table_entry(host_kvm, hyp_vm);
+	if (ret < 0)
+		goto err_unlock;
+
+	ret = kvm_guest_prepare_stage2(hyp_vm, pgd);
+	if (ret)
+		goto err_remove_vm_table_entry;
+	hyp_spin_unlock(&vm_table_lock);
+
+	return hyp_vm->kvm.arch.pkvm.handle;
+
+err_remove_vm_table_entry:
+	remove_vm_table_entry(hyp_vm->kvm.arch.pkvm.handle);
+err_unlock:
+	hyp_spin_unlock(&vm_table_lock);
+err_remove_mappings:
+	unmap_donated_memory(hyp_vm, vm_size);
+	unmap_donated_memory(pgd, pgd_size);
+err_unpin_kvm:
+	hyp_unpin_shared_mem(host_kvm, host_kvm + 1);
+	return ret;
+}
+
+/*
+ * Initialize the hypervisor copy of the protected vCPU state using the
+ * memory donated by the host.
+ *
+ * handle: The handle for the protected vm.
+ * host_vcpu: A pointer to the corresponding host vcpu.
+ * vcpu_hva: The host va of the area being donated for the vcpu state.
+ *	     Must be page aligned. The size of the area must be equal to
+ *	     the page-aligned size of 'struct pkvm_hyp_vcpu'.
+ * Return 0 on success, negative error code on failure.
+ */
+int __pkvm_init_vcpu(pkvm_handle_t handle, struct kvm_vcpu *host_vcpu,
+		     unsigned long vcpu_hva)
+{
+	struct pkvm_hyp_vcpu *hyp_vcpu;
+	struct pkvm_hyp_vm *hyp_vm;
+	unsigned int idx;
+	int ret;
+
+	hyp_vcpu = map_donated_memory(vcpu_hva, sizeof(*hyp_vcpu));
+	if (!hyp_vcpu)
+		return -ENOMEM;
+
+	hyp_spin_lock(&vm_table_lock);
+
+	hyp_vm = get_vm_by_handle(handle);
+	if (!hyp_vm) {
+		ret = -ENOENT;
+		goto unlock;
+	}
+
+	idx = hyp_vm->nr_vcpus;
+	if (idx >= hyp_vm->kvm.created_vcpus) {
+		ret = -EINVAL;
+		goto unlock;
+	}
+
+	ret = init_pkvm_hyp_vcpu(hyp_vcpu, hyp_vm, host_vcpu, idx);
+	if (ret)
+		goto unlock;
+
+	hyp_vm->vcpus[idx] = hyp_vcpu;
+	hyp_vm->nr_vcpus++;
+unlock:
+	hyp_spin_unlock(&vm_table_lock);
+
+	if (ret)
+		unmap_donated_memory(hyp_vcpu, sizeof(*hyp_vcpu));
+
+	return ret;
+}
+
+static void
+teardown_donated_memory(struct kvm_hyp_memcache *mc, void *addr, size_t size)
+{
+	size = PAGE_ALIGN(size);
+	memset(addr, 0, size);
+
+	for (void *start = addr; start < addr + size; start += PAGE_SIZE)
+		push_hyp_memcache(mc, start, hyp_virt_to_phys);
+
+	unmap_donated_memory_noclear(addr, size);
+}
+
+int __pkvm_teardown_vm(pkvm_handle_t handle)
+{
+	struct kvm_hyp_memcache *mc;
+	struct pkvm_hyp_vm *hyp_vm;
+	struct kvm *host_kvm;
+	unsigned int idx;
+	size_t vm_size;
+	int err;
+
+	hyp_spin_lock(&vm_table_lock);
+	hyp_vm = get_vm_by_handle(handle);
+	if (!hyp_vm) {
+		err = -ENOENT;
+		goto err_unlock;
+	}
+
+	if (WARN_ON(hyp_page_count(hyp_vm))) {
+		err = -EBUSY;
+		goto err_unlock;
+	}
+
+	host_kvm = hyp_vm->host_kvm;
+
+	/* Ensure the VMID is clean before it can be reallocated */
+	__kvm_tlb_flush_vmid(&hyp_vm->kvm.arch.mmu);
+	remove_vm_table_entry(handle);
+	hyp_spin_unlock(&vm_table_lock);
+
+	/* Reclaim guest pages (including page-table pages) */
+	mc = &host_kvm->arch.pkvm.teardown_mc;
+	reclaim_guest_pages(hyp_vm, mc);
+	unpin_host_vcpus(hyp_vm->vcpus, hyp_vm->nr_vcpus);
+
+	/* Push the metadata pages to the teardown memcache */
+	for (idx = 0; idx < hyp_vm->nr_vcpus; ++idx) {
+		struct pkvm_hyp_vcpu *hyp_vcpu = hyp_vm->vcpus[idx];
+
+		teardown_donated_memory(mc, hyp_vcpu, sizeof(*hyp_vcpu));
+	}
+
+	vm_size = pkvm_get_hyp_vm_size(hyp_vm->kvm.created_vcpus);
+	teardown_donated_memory(mc, hyp_vm, vm_size);
+	hyp_unpin_shared_mem(host_kvm, host_kvm + 1);
+	return 0;
+
+err_unlock:
+	hyp_spin_unlock(&vm_table_lock);
+	return err;
+}