1 files changed, 336 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
new file mode 100644
index 000000000000..e8d4ea2fcfa0
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -0,0 +1,336 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Google LLC
+ * Author: Quentin Perret <qperret@google.com>
+ */
+
+#include <linux/kvm_host.h>
+#include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
+#include <asm/kvm_pgtable.h>
+#include <asm/kvm_pkvm.h>
+
+#include <nvhe/early_alloc.h>
+#include <nvhe/fixed_config.h>
+#include <nvhe/gfp.h>
+#include <nvhe/memory.h>
+#include <nvhe/mem_protect.h>
+#include <nvhe/mm.h>
+#include <nvhe/trap_handler.h>
+
+unsigned long hyp_nr_cpus;
+
+#define hyp_percpu_size ((unsigned long)__per_cpu_end - \
+			 (unsigned long)__per_cpu_start)
+
+static void *vmemmap_base;
+static void *hyp_pgt_base;
+static void *host_s2_pgt_base;
+static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
+static struct hyp_pool hpool;
+
+static int divide_memory_pool(void *virt, unsigned long size)
+{
+	unsigned long vstart, vend, nr_pages;
+
+	hyp_early_alloc_init(virt, size);
+
+	hyp_vmemmap_range(__hyp_pa(virt), size, &vstart, &vend);
+	nr_pages = (vend - vstart) >> PAGE_SHIFT;
+	vmemmap_base = hyp_early_alloc_contig(nr_pages);
+	if (!vmemmap_base)
+		return -ENOMEM;
+
+	nr_pages = hyp_s1_pgtable_pages();
+	hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
+	if (!hyp_pgt_base)
+		return -ENOMEM;
+
+	nr_pages = host_s2_pgtable_pages();
+	host_s2_pgt_base = hyp_early_alloc_contig(nr_pages);
+	if (!host_s2_pgt_base)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
+				 unsigned long *per_cpu_base,
+				 u32 hyp_va_bits)
+{
+	void *start, *end, *virt = hyp_phys_to_virt(phys);
+	unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
+	enum kvm_pgtable_prot prot;
+	int ret, i;
+
+	/* Recreate the hyp page-table using the early page allocator */
+	hyp_early_alloc_init(hyp_pgt_base, pgt_size);
+	ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
+				   &hyp_early_alloc_mm_ops);
+	if (ret)
+		return ret;
+
+	ret = hyp_create_idmap(hyp_va_bits);
+	if (ret)
+		return ret;
+
+	ret = hyp_map_vectors();
+	if (ret)
+		return ret;
+
+	ret = hyp_back_vmemmap(phys, size, hyp_virt_to_phys(vmemmap_base));
+	if (ret)
+		return ret;
+
+	ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
+	if (ret)
+		return ret;
+
+	ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
+	if (ret)
+		return ret;
+
+	ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
+	if (ret)
+		return ret;
+
+	ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < hyp_nr_cpus; i++) {
+		struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i);
+		unsigned long hyp_addr;
+
+		start = (void *)kern_hyp_va(per_cpu_base[i]);
+		end = start + PAGE_ALIGN(hyp_percpu_size);
+		ret = pkvm_create_mappings(start, end, PAGE_HYP);
+		if (ret)
+			return ret;
+
+		/*
+		 * Allocate a contiguous HYP private VA range for the stack
+		 * and guard page. The allocation is also aligned based on
+		 * the order of its size.
+		 */
+		ret = pkvm_alloc_private_va_range(PAGE_SIZE * 2, &hyp_addr);
+		if (ret)
+			return ret;
+
+		/*
+		 * Since the stack grows downwards, map the stack to the page
+		 * at the higher address and leave the lower guard page
+		 * unbacked.
+		 *
+		 * Any valid stack address now has the PAGE_SHIFT bit as 1
+		 * and addresses corresponding to the guard page have the
+		 * PAGE_SHIFT bit as 0 - this is used for overflow detection.
+		 */
+		hyp_spin_lock(&pkvm_pgd_lock);
+		ret = kvm_pgtable_hyp_map(&pkvm_pgtable, hyp_addr + PAGE_SIZE,
+					PAGE_SIZE, params->stack_pa, PAGE_HYP);
+		hyp_spin_unlock(&pkvm_pgd_lock);
+		if (ret)
+			return ret;
+
+		/* Update stack_hyp_va to end of the stack's private VA range */
+		params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE);
+	}
+
+	/*
+	 * Map the host's .bss and .rodata sections RO in the hypervisor, but
+	 * transfer the ownership from the host to the hypervisor itself to
+	 * make sure it can't be donated or shared with another entity.
+	 *
+	 * The ownership transition requires matching changes in the host
+	 * stage-2. This will be done later (see finalize_host_mappings()) once
+	 * the hyp_vmemmap is addressable.
+	 */
+	prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED);
+	ret = pkvm_create_mappings(__start_rodata, __end_rodata, prot);
+	if (ret)
+		return ret;
+
+	ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, prot);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void update_nvhe_init_params(void)
+{
+	struct kvm_nvhe_init_params *params;
+	unsigned long i;
+
+	for (i = 0; i < hyp_nr_cpus; i++) {
+		params = per_cpu_ptr(&kvm_init_params, i);
+		params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
+		dcache_clean_inval_poc((unsigned long)params,
+				    (unsigned long)params + sizeof(*params));
+	}
+}
+
+static void *hyp_zalloc_hyp_page(void *arg)
+{
+	return hyp_alloc_pages(&hpool, 0);
+}
+
+static void hpool_get_page(void *addr)
+{
+	hyp_get_page(&hpool, addr);
+}
+
+static void hpool_put_page(void *addr)
+{
+	hyp_put_page(&hpool, addr);
+}
+
+static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level,
+					 kvm_pte_t *ptep,
+					 enum kvm_pgtable_walk_flags flag,
+					 void * const arg)
+{
+	struct kvm_pgtable_mm_ops *mm_ops = arg;
+	enum kvm_pgtable_prot prot;
+	enum pkvm_page_state state;
+	kvm_pte_t pte = *ptep;
+	phys_addr_t phys;
+
+	if (!kvm_pte_valid(pte))
+		return 0;
+
+	/*
+	 * Fix-up the refcount for the page-table pages as the early allocator
+	 * was unable to access the hyp_vmemmap and so the buddy allocator has
+	 * initialised the refcount to '1'.
+	 */
+	mm_ops->get_page(ptep);
+	if (flag != KVM_PGTABLE_WALK_LEAF)
+		return 0;
+
+	if (level != (KVM_PGTABLE_MAX_LEVELS - 1))
+		return -EINVAL;
+
+	phys = kvm_pte_to_phys(pte);
+	if (!addr_is_memory(phys))
+		return -EINVAL;
+
+	/*
+	 * Adjust the host stage-2 mappings to match the ownership attributes
+	 * configured in the hypervisor stage-1.
+	 */
+	state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(pte));
+	switch (state) {
+	case PKVM_PAGE_OWNED:
+		return host_stage2_set_owner_locked(phys, PAGE_SIZE, pkvm_hyp_id);
+	case PKVM_PAGE_SHARED_OWNED:
+		prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED);
+		break;
+	case PKVM_PAGE_SHARED_BORROWED:
+		prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return host_stage2_idmap_locked(phys, PAGE_SIZE, prot);
+}
+
+static int finalize_host_mappings(void)
+{
+	struct kvm_pgtable_walker walker = {
+		.cb	= finalize_host_mappings_walker,
+		.flags	= KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
+		.arg	= pkvm_pgtable.mm_ops,
+	};
+	int i, ret;
+
+	for (i = 0; i < hyp_memblock_nr; i++) {
+		struct memblock_region *reg = &hyp_memory[i];
+		u64 start = (u64)hyp_phys_to_virt(reg->base);
+
+		ret = kvm_pgtable_walk(&pkvm_pgtable, start, reg->size, &walker);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+void __noreturn __pkvm_init_finalise(void)
+{
+	struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
+	struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt;
+	unsigned long nr_pages, reserved_pages, pfn;
+	int ret;
+
+	/* Now that the vmemmap is backed, install the full-fledged allocator */
+	pfn = hyp_virt_to_pfn(hyp_pgt_base);
+	nr_pages = hyp_s1_pgtable_pages();
+	reserved_pages = hyp_early_alloc_nr_used_pages();
+	ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
+	if (ret)
+		goto out;
+
+	ret = kvm_host_prepare_stage2(host_s2_pgt_base);
+	if (ret)
+		goto out;
+
+	pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
+		.zalloc_page = hyp_zalloc_hyp_page,
+		.phys_to_virt = hyp_phys_to_virt,
+		.virt_to_phys = hyp_virt_to_phys,
+		.get_page = hpool_get_page,
+		.put_page = hpool_put_page,
+		.page_count = hyp_page_count,
+	};
+	pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
+
+	ret = finalize_host_mappings();
+	if (ret)
+		goto out;
+
+out:
+	/*
+	 * We tail-called to here from handle___pkvm_init() and will not return,
+	 * so make sure to propagate the return value to the host.
+	 */
+	cpu_reg(host_ctxt, 1) = ret;
+
+	__host_enter(host_ctxt);
+}
+
+int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
+		unsigned long *per_cpu_base, u32 hyp_va_bits)
+{
+	struct kvm_nvhe_init_params *params;
+	void *virt = hyp_phys_to_virt(phys);
+	void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
+	int ret;
+
+	BUG_ON(kvm_check_pvm_sysreg_table());
+
+	if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
+		return -EINVAL;
+
+	hyp_spin_lock_init(&pkvm_pgd_lock);
+	hyp_nr_cpus = nr_cpus;
+
+	ret = divide_memory_pool(virt, size);
+	if (ret)
+		return ret;
+
+	ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
+	if (ret)
+		return ret;
+
+	update_nvhe_init_params();
+
+	/* Jump in the idmap page to switch to the new page-tables */
+	params = this_cpu_ptr(&kvm_init_params);
+	fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
+	fn(__hyp_pa(params), __pkvm_init_finalise);
+
+	unreachable();
+}