/*
 * Copyright (C) 2018 Intel Corporation. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <vm.h>
#include <e820.h>
#include <zeropage.h>
#include <boot_context.h>
#include <ept.h>
#include <mmu.h>
#include <multiboot.h>
#include <errno.h>
#include <sprintf.h>
#include <logmsg.h>

#define NUM_REMAIN_1G_PAGES	3UL

static void prepare_bsp_gdt(struct acrn_vm *vm)
{
	size_t gdt_len;
	uint64_t gdt_base_hpa;

	gdt_base_hpa = gpa2hpa(vm, boot_context.gdt.base);
	if (boot_context.gdt.base != gdt_base_hpa) {
		gdt_len = ((size_t)boot_context.gdt.limit + 1U) / sizeof(uint8_t);
		(void)copy_to_gpa(vm, hpa2hva(boot_context.gdt.base), boot_context.gdt.base, gdt_len);
	}

	return;
}

/**
 * @pre zp != NULL && vm != NULL
 */
static uint32_t create_zeropage_e820(struct zero_page *zp, const struct acrn_vm *vm)
{
	uint32_t entry_num = vm->e820_entry_num;
	struct e820_entry *zp_e820 = zp->entries;
	struct e820_entry *vm_e820 = vm->e820_entries;

	if ((zp_e820 == NULL) || (vm_e820 == NULL) || (entry_num == 0U) || (entry_num > E820_MAX_ENTRIES)) {
		pr_err("e820 create error");
		entry_num = 0U;
	} else {
		(void)memcpy_s((void *)zp_e820, entry_num * sizeof(struct e820_entry),
			(void *)vm_e820, entry_num * sizeof(struct e820_entry));
	}
	return entry_num;
}

static uint64_t create_zero_page(struct acrn_vm *vm)
{
	struct zero_page *zeropage;
	struct sw_linux *linux_info = &(vm->sw.linux_info);
	struct sw_kernel_info *sw_kernel = &(vm->sw.kernel_info);
	struct zero_page *hva;
	uint64_t gpa, addr;

	/* Set zeropage in Linux Guest RAM region just past boot args */
	gpa = (uint64_t)linux_info->bootargs_load_addr + MEM_4K;
	hva = (struct zero_page *)gpa2hva(vm, gpa);
	zeropage = hva;

	stac();
	/* clear the zeropage */
	(void)memset(zeropage, 0U, MEM_2K);

	/* copy part of the header into the zero page */
	hva = (struct zero_page *)gpa2hva(vm, (uint64_t)sw_kernel->kernel_load_addr);
	(void)memcpy_s(&(zeropage->hdr), sizeof(zeropage->hdr),
				&(hva->hdr), sizeof(hva->hdr));

	/* See if kernel has a RAM disk */
	if (linux_info->ramdisk_src_addr != NULL) {
		/* Copy ramdisk load_addr and size in zeropage header structure
		 */
		addr = (uint64_t)linux_info->ramdisk_load_addr;
		zeropage->hdr.ramdisk_addr = (uint32_t)addr;
		zeropage->hdr.ramdisk_size = (uint32_t)linux_info->ramdisk_size;
	}

	/* Copy bootargs load_addr in zeropage header structure */
	addr = (uint64_t)linux_info->bootargs_load_addr;
	zeropage->hdr.bootargs_addr = (uint32_t)addr;

	/* set constant arguments in zero page */
	zeropage->hdr.loader_type = 0xffU;
	zeropage->hdr.load_flags |= (1U << 5U);	/* quiet */

	/* Create/add e820 table entries in zeropage */
	zeropage->e820_nentries = (uint8_t)create_zeropage_e820(zeropage, vm);
	clac();

	/* Return Physical Base Address of zeropage */
	return gpa;
}

int32_t general_sw_loader(struct acrn_vm *vm)
{
	int32_t ret = 0;
	char  dyn_bootargs[100] = {0};
	uint32_t kernel_entry_offset;
	struct zero_page *zeropage;
	struct sw_linux *linux_info = &(vm->sw.linux_info);
	struct sw_kernel_info *sw_kernel = &(vm->sw.kernel_info);
	/* get primary vcpu */
	struct acrn_vcpu *vcpu = vcpu_from_vid(vm, BOOT_CPU_ID);
	const struct acrn_vm_config *vm_config = get_vm_config(vm->vm_id);

	pr_dbg("Loading guest to run-time location");

	prepare_bsp_gdt(vm);
	set_vcpu_regs(vcpu, &boot_context);

	/* calculate the kernel entry point */
	zeropage = (struct zero_page *)sw_kernel->kernel_src_addr;
	stac();
	kernel_entry_offset = (uint32_t)(zeropage->hdr.setup_sects + 1U) * 512U;
	clac();
	if (vcpu->arch.cpu_mode == CPU_MODE_64BIT) {
		/* 64bit entry is the 512bytes after the start */
		kernel_entry_offset += 512U;
	}

	sw_kernel->kernel_entry_addr = (void *)((uint64_t)sw_kernel->kernel_load_addr + kernel_entry_offset);

	/* Set VCPU entry point to kernel entry */
	vcpu_set_rip(vcpu, (uint64_t)sw_kernel->kernel_entry_addr);
	pr_info("%s, VM %hu VCPU %hu Entry: 0x%016llx ", __func__, vm->vm_id, vcpu->vcpu_id,
		sw_kernel->kernel_entry_addr);

	/* Copy the guest kernel image to its run-time location */
	(void)copy_to_gpa(vm, sw_kernel->kernel_src_addr,
		(uint64_t)sw_kernel->kernel_load_addr, sw_kernel->kernel_size);

	/* See if guest is a Linux guest */
	if (vm->sw.kernel_type == VM_LINUX_GUEST) {
		uint32_t i;

		/* Documentation states: ebx=0, edi=0, ebp=0, esi=ptr to
		 * zeropage
		 */
		for (i = 0U; i < NUM_GPRS; i++) {
			vcpu_set_gpreg(vcpu, i, 0UL);
		}

		/* Copy Guest OS bootargs to its load location */
		(void)copy_to_gpa(vm, linux_info->bootargs_src_addr,
			(uint64_t)linux_info->bootargs_load_addr,
			(strnlen_s((char *)linux_info->bootargs_src_addr, MAX_BOOTARGS_SIZE) + 1U));

		/* add "hugepagesz=1G hugepages=x" to cmdline for 1G hugepage
		 * reserving. Current strategy is "total_mem_size in Giga -
		 * remained 1G pages" for reserving.
		 */
		if (is_sos_vm(vm)) {
			int64_t reserving_1g_pages;

			reserving_1g_pages = (vm_config->memory.size >> 30U) - NUM_REMAIN_1G_PAGES;
			if (reserving_1g_pages > 0) {
				snprintf(dyn_bootargs, 100U, " hugepagesz=1G hugepages=%lld", reserving_1g_pages);
				(void)copy_to_gpa(vm, dyn_bootargs, ((uint64_t)linux_info->bootargs_load_addr
					+ linux_info->bootargs_size),
					(strnlen_s(dyn_bootargs, 99U) + 1U));
			}
		}

		/* Check if a RAM disk is present with Linux guest */
		if (linux_info->ramdisk_src_addr != NULL) {
			/* Copy RAM disk to its load location */
			(void)copy_to_gpa(vm, linux_info->ramdisk_src_addr,
				(uint64_t)linux_info->ramdisk_load_addr,
				linux_info->ramdisk_size);
		}

		/* Create Zeropage and copy Physical Base Address of Zeropage
		 * in RSI
		 */
		vcpu_set_gpreg(vcpu, CPU_REG_RSI, create_zero_page(vm));

		pr_info("%s, RSI pointing to zero page for VM %d at GPA %X",
				__func__, vm->vm_id, vcpu_get_gpreg(vcpu, CPU_REG_RSI));

	} else {
		pr_err("%s, Loading VM SW failed", __func__);
		ret = -EINVAL;
	}

	return ret;
}