static int init_hyp_mode()

in kvm/arm.c [1878:2026]

• 100 lines of code
• 17 McCabe index (conditional complexity)

static int init_hyp_mode(void)
{
	u32 hyp_va_bits;
	int cpu;
	int err = -ENOMEM;

	/*
	 * The protected Hyp-mode cannot be initialized if the memory pool
	 * allocation has failed.
	 */
	if (is_protected_kvm_enabled() && !hyp_mem_base)
		goto out_err;

	/*
	 * Allocate Hyp PGD and setup Hyp identity mapping
	 */
	err = kvm_mmu_init(&hyp_va_bits);
	if (err)
		goto out_err;

	/*
	 * Allocate stack pages for Hypervisor-mode
	 */
	for_each_possible_cpu(cpu) {
		unsigned long stack_page;

		stack_page = __get_free_page(GFP_KERNEL);
		if (!stack_page) {
			err = -ENOMEM;
			goto out_err;
		}

		per_cpu(kvm_arm_hyp_stack_page, cpu) = stack_page;
	}

	/*
	 * Allocate and initialize pages for Hypervisor-mode percpu regions.
	 */
	for_each_possible_cpu(cpu) {
		struct page *page;
		void *page_addr;

		page = alloc_pages(GFP_KERNEL, nvhe_percpu_order());
		if (!page) {
			err = -ENOMEM;
			goto out_err;
		}

		page_addr = page_address(page);
		memcpy(page_addr, CHOOSE_NVHE_SYM(__per_cpu_start), nvhe_percpu_size());
		kvm_arm_hyp_percpu_base[cpu] = (unsigned long)page_addr;
	}

	/*
	 * Map the Hyp-code called directly from the host
	 */
	err = create_hyp_mappings(kvm_ksym_ref(__hyp_text_start),
				  kvm_ksym_ref(__hyp_text_end), PAGE_HYP_EXEC);
	if (err) {
		kvm_err("Cannot map world-switch code\n");
		goto out_err;
	}

	err = create_hyp_mappings(kvm_ksym_ref(__hyp_rodata_start),
				  kvm_ksym_ref(__hyp_rodata_end), PAGE_HYP_RO);
	if (err) {
		kvm_err("Cannot map .hyp.rodata section\n");
		goto out_err;
	}

	err = create_hyp_mappings(kvm_ksym_ref(__start_rodata),
				  kvm_ksym_ref(__end_rodata), PAGE_HYP_RO);
	if (err) {
		kvm_err("Cannot map rodata section\n");
		goto out_err;
	}

	/*
	 * .hyp.bss is guaranteed to be placed at the beginning of the .bss
	 * section thanks to an assertion in the linker script. Map it RW and
	 * the rest of .bss RO.
	 */
	err = create_hyp_mappings(kvm_ksym_ref(__hyp_bss_start),
				  kvm_ksym_ref(__hyp_bss_end), PAGE_HYP);
	if (err) {
		kvm_err("Cannot map hyp bss section: %d\n", err);
		goto out_err;
	}

	err = create_hyp_mappings(kvm_ksym_ref(__hyp_bss_end),
				  kvm_ksym_ref(__bss_stop), PAGE_HYP_RO);
	if (err) {
		kvm_err("Cannot map bss section\n");
		goto out_err;
	}

	/*
	 * Map the Hyp stack pages
	 */
	for_each_possible_cpu(cpu) {
		char *stack_page = (char *)per_cpu(kvm_arm_hyp_stack_page, cpu);
		err = create_hyp_mappings(stack_page, stack_page + PAGE_SIZE,
					  PAGE_HYP);

		if (err) {
			kvm_err("Cannot map hyp stack\n");
			goto out_err;
		}
	}

	for_each_possible_cpu(cpu) {
		char *percpu_begin = (char *)kvm_arm_hyp_percpu_base[cpu];
		char *percpu_end = percpu_begin + nvhe_percpu_size();

		/* Map Hyp percpu pages */
		err = create_hyp_mappings(percpu_begin, percpu_end, PAGE_HYP);
		if (err) {
			kvm_err("Cannot map hyp percpu region\n");
			goto out_err;
		}

		/* Prepare the CPU initialization parameters */
		cpu_prepare_hyp_mode(cpu);
	}

	if (is_protected_kvm_enabled()) {
		init_cpu_logical_map();

		if (!init_psci_relay()) {
			err = -ENODEV;
			goto out_err;
		}
	}

	if (is_protected_kvm_enabled()) {
		err = kvm_hyp_init_protection(hyp_va_bits);
		if (err) {
			kvm_err("Failed to init hyp memory protection\n");
			goto out_err;
		}
	}

	return 0;

out_err:
	teardown_hyp_mode();
	kvm_err("error initializing Hyp mode: %d\n", err);
	return err;
}