acrn-hypervisor/hypervisor/arch/riscv/mmu.c

/*
 * Copyright (C) 2023-2025 Intel Corporation.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
#include <types.h>
#include <rtl.h>
#include <mmu.h>
#include <asm/qemu.h>
#include <logmsg.h>

void set_paging_supervisor(__unused uint64_t base, __unused uint64_t size)
{
}

static struct page_pool ppt_page_pool;
static void *ppt_mmu_top_addr;
uint64_t init_satp;

extern uint8_t _code_start;
extern uint8_t _code_end;

/**
 * Riscv mmio memory layout is continuous and it support 1G huge
 * page by default, base on this, we assume it only consume one VPN3/2 page,
 * and preserve 4 VPN1 page to deal with memory map without 1G alignment.
 * for VPN0 page, we only preserve uart mmio related 2 pages.
 *
 * FIXME: The number need to be calculated according to the actual platform
 * memory layout, which is to be generated by config tool.
 */
#define PPT_VPN3_PAGE_NUM      1UL
#define PPT_VPN2_PAGE_NUM      1UL
#define PPT_VPN1_PAGE_NUM      4UL
#define PPT_VPN0_PAGE_NUM      2UL

#define PPT_PAGE_NUM_SUM   (PPT_VPN3_PAGE_NUM + PPT_VPN2_PAGE_NUM + PPT_VPN1_PAGE_NUM + PPT_VPN0_PAGE_NUM)
#define PPT_PAGE_NUM     roundup(PPT_PAGE_NUM_SUM, 64U)

DEFINE_PAGE_TABLES(ppt_pages, PPT_PAGE_NUM);
DEFINE_PAGE_TABLE(ppt_pages_bitmap);

static bool large_page_support(enum _page_table_level level, uint64_t __unused prot)
{
	if (level == PGT_LVL1|| level == PGT_LVL2)
		return true;
	else
		return false;
}

static void ppt_flush_cache_pagewalk(const void* entry __attribute__((unused)))
{
}

static uint64_t ppt_pgentry_present(uint64_t pte)
{
	return pte & PAGE_V;
}

static inline void ppt_set_pgentry(uint64_t *pte, uint64_t page, uint64_t prot, enum _page_table_level __unused level,
		bool is_leaf, const struct pgtable *table)
{
	uint64_t prot_tmp;
	if (!is_leaf) {
		prot_tmp = PAGE_V;
	} else {
		prot_tmp = prot;
	}
	make_pgentry(pte, page, prot_tmp, table);
}

static const struct pgtable ppt_pgtable = {
	.pool = &ppt_page_pool,
	.large_page_support = large_page_support,
	.pgentry_present = ppt_pgentry_present,
	.flush_cache_pagewalk = ppt_flush_cache_pagewalk,
	.set_pgentry = ppt_set_pgentry,
};

/* TODO: need to formally get the value either from
 * config tool or from DTS runtime parsing.
 */
static uint64_t get_board_hv_device_start(void)
{
	return 0UL;
}

/* TODO: need to formally get the value either from
 * config tool or from DTS runtime parsing.
 */
static uint64_t get_board_hv_device_size(void)
{
	return 0x80000000UL;
}

static bool switch_satp(uint64_t satp_value)
{
	/**
	 * Here is to detect whether SV48 is supported
	 * by the platform by writing the MODE in satp
	 * register, which is a WARL field. According to
	 * The RISC-V Instruction Set Manual volume II,
	 * if satp is written with an unsupported MODE,
	 * the entire write has no effect; no fields in
	 * satp are modified.
	 */
	set_satp(satp_value);
	return (cpu_csr_read(satp) == satp_value);
}

/**
 * TODO: need to detect existence of svpbmt extension to support PAGE_ATTR_IO
 * and PAGE_ATTR_PMA for mapping.
 */
static void init_hv_mapping(void)
{
	ppt_mmu_top_addr = (uint64_t *)alloc_page(&ppt_page_pool);

	/*TODO: The SUM bit in sstatus is 0, meaning SMAP is enabled
	 * however, SMAP is provided by smepmp extension, we need to detect
	 * its existence from DTS.
	 */
	pgtable_add_map((uint64_t *)ppt_mmu_top_addr, get_board_hv_device_start(),
		get_board_hv_device_start(), get_board_hv_device_size(),
		PAGE_V | PAGE_R | PAGE_W,
		&ppt_pgtable);

	/*TODO: Only map PAGE_X for text section*/
	pgtable_add_map((uint64_t *)ppt_mmu_top_addr, CONFIG_HV_RAM_START,
		CONFIG_HV_RAM_START, (&_code_end - &_code_start),
		PAGE_V | PAGE_X | PAGE_R | PAGE_W,
		&ppt_pgtable);

	init_satp = ((uint64_t)ppt_mmu_top_addr >> PAGE_SHIFT) | SATP_MODE_SV48;
	if (!switch_satp(init_satp)) {
		panic("Only support SV48 mode !");
	}
}

void init_paging(void)
{
	init_page_pool(&ppt_page_pool, (uint64_t *)ppt_pages,
			(uint64_t *)ppt_pages_bitmap, PPT_PAGE_NUM);

	init_hv_mapping();
}

void enable_paging(void)
{
	set_satp(init_satp);
}