lib/efi.c

/*
 * EFI-related functions to set up and run test cases in EFI
 *
 * Copyright (c) 2021, SUSE, Varad Gautam <varad.gautam@suse.com>
 * Copyright (c) 2021, Google Inc, Zixuan Wang <zixuanwang@google.com>
 *
 * SPDX-License-Identifier: LGPL-2.0-or-later
 */

#include "efi.h"
#include <libcflat.h>
#include <asm/setup.h>

/* From lib/argv.c */
extern int __argc, __envc;
extern char *__argv[100];
extern char *__environ[200];

extern int main(int argc, char **argv, char **envp);

efi_system_table_t *efi_system_table = NULL;

static void efi_free_pool(void *ptr)
{
	efi_bs_call(free_pool, ptr);
}

efi_status_t efi_get_memory_map(struct efi_boot_memmap *map)
{
	efi_memory_desc_t *m = NULL;
	efi_status_t status;
	unsigned long key = 0, map_size = 0, desc_size = 0;
	u32 desc_ver;

	status = efi_bs_call(get_memory_map, &map_size,
			     NULL, &key, &desc_size, &desc_ver);
	if (status != EFI_BUFFER_TOO_SMALL || map_size == 0)
		goto out;

	/*
	 * Pad map_size with additional descriptors so we don't need to
	 * retry.
	 */
	map_size += 4 * desc_size;
	*map->buff_size = map_size;
	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
			     map_size, (void **)&m);
	if (status != EFI_SUCCESS)
		goto out;

	/* Get the map. */
	status = efi_bs_call(get_memory_map, &map_size,
			     m, &key, &desc_size, &desc_ver);
	if (status != EFI_SUCCESS) {
		efi_free_pool(m);
		goto out;
	}

	*map->desc_ver = desc_ver;
	*map->desc_size = desc_size;
	*map->map_size = map_size;
	*map->key_ptr = key;
out:
	*map->map = m;
	return status;
}

efi_status_t efi_exit_boot_services(void *handle, struct efi_boot_memmap *map)
{
	return efi_bs_call(exit_boot_services, handle, *map->key_ptr);
}

efi_status_t efi_get_system_config_table(efi_guid_t table_guid, void **table)
{
	size_t i;
	efi_config_table_t *tables;

	tables = (efi_config_table_t *)efi_system_table->tables;
	for (i = 0; i < efi_system_table->nr_tables; i++) {
		if (!memcmp(&table_guid, &tables[i].guid, sizeof(efi_guid_t))) {
			*table = tables[i].table;
			return EFI_SUCCESS;
		}
	}
	return EFI_NOT_FOUND;
}

static void efi_exit(efi_status_t code)
{
	exit(code);

	/*
	 * Fallback to UEFI reset_system() service, in case testdev is
	 * missing and exit() does not properly exit.
	 */
	efi_rs_call(reset_system, EFI_RESET_SHUTDOWN, code, 0, NULL);
}

efi_status_t efi_main(efi_handle_t handle, efi_system_table_t *sys_tab)
{
	int ret;
	efi_status_t status;
	efi_bootinfo_t efi_bootinfo;

	efi_system_table = sys_tab;

	/* Memory map struct values */
	efi_memory_desc_t *map = NULL;
	unsigned long map_size = 0, desc_size = 0, key = 0, buff_size = 0;
	u32 desc_ver;

	/* Set up efi_bootinfo */
	efi_bootinfo.mem_map.map = &map;
	efi_bootinfo.mem_map.map_size = &map_size;
	efi_bootinfo.mem_map.desc_size = &desc_size;
	efi_bootinfo.mem_map.desc_ver = &desc_ver;
	efi_bootinfo.mem_map.key_ptr = &key;
	efi_bootinfo.mem_map.buff_size = &buff_size;

	/* Get EFI memory map */
	status = efi_get_memory_map(&efi_bootinfo.mem_map);
	if (status != EFI_SUCCESS) {
		printf("Failed to get memory map\n");
		goto efi_main_error;
	}

	/* 
	 * Exit EFI boot services, let kvm-unit-tests take full control of the
	 * guest
	 */
	status = efi_exit_boot_services(handle, &efi_bootinfo.mem_map);
	if (status != EFI_SUCCESS) {
		printf("Failed to exit boot services\n");
		goto efi_main_error;
	}

	/* Set up arch-specific resources */
	status = setup_efi(&efi_bootinfo);
	if (status != EFI_SUCCESS) {
		printf("Failed to set up arch-specific resources\n");
		goto efi_main_error;
	}

	/* Run the test case */
	ret = main(__argc, __argv, __environ);

	/* Shutdown the guest VM */
	efi_exit(ret);

	/* Unreachable */
	return EFI_UNSUPPORTED;

efi_main_error:
	/* Shutdown the guest with error EFI status */
	efi_exit(status);

	/* Unreachable */
	return EFI_UNSUPPORTED;
}