acrn-hypervisor/hypervisor/arch/x86/page.c

76 lines
1.9 KiB
C

/*
* Copyright (C) 2018-2024 Intel Corporation.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <types.h>
#include <asm/lib/bits.h>
#include <asm/page.h>
#include <logmsg.h>
/**
* @addtogroup hwmgmt_page
*
* @{
*/
/**
* @file
* @brief Implementation of page management.
*
* This file provides the core functionality required for allocating and freeing memory pages. It's a fundamental
* support to manage memory resources.
*/
struct page *alloc_page(struct page_pool *pool)
{
struct page *page = NULL;
uint64_t loop_idx, idx, bit;
spinlock_obtain(&pool->lock);
for (loop_idx = pool->last_hint_id;
loop_idx < (pool->last_hint_id + pool->bitmap_size); loop_idx++) {
idx = loop_idx % pool->bitmap_size;
if (*(pool->bitmap + idx) != ~0UL) {
bit = ffz64(*(pool->bitmap + idx));
bitmap_set_nolock(bit, pool->bitmap + idx);
page = pool->start_page + ((idx << 6U) + bit);
pool->last_hint_id = idx;
break;
}
}
spinlock_release(&pool->lock);
ASSERT(page != NULL, "no page aviable!");
page = (page != NULL) ? page : pool->dummy_page;
if (page == NULL) {
/* For HV MMU page-table mapping, we didn't use dummy page when there's no page
* available in the page pool. This because we only do MMU page-table mapping on
* the early boot time and we reserve enough pages for it. After that, we would
* not do any MMU page-table mapping. We would let the system boot fail when page
* allocation failed.
*/
panic("no dummy aviable!");
}
(void)memset(page, 0U, PAGE_SIZE);
return page;
}
/*
*@pre: ((page - pool->start_page) >> 6U) < pool->bitmap_size
*/
void free_page(struct page_pool *pool, struct page *page)
{
uint64_t idx, bit;
spinlock_obtain(&pool->lock);
idx = (page - pool->start_page) >> 6U;
bit = (page - pool->start_page) & 0x3fUL;
bitmap_clear_nolock(bit, pool->bitmap + idx);
spinlock_release(&pool->lock);
}
/**
* @}
*/