x86_fake_mem.c (1918B)
1// SPDX-License-Identifier: GPL-2.0 2/* Copyright(c) 2019 Intel Corporation. All rights reserved. */ 3#include <linux/efi.h> 4#include <asm/e820/api.h> 5#include "fake_mem.h" 6 7void __init efi_fake_memmap_early(void) 8{ 9 int i; 10 11 /* 12 * The late efi_fake_mem() call can handle all requests if 13 * EFI_MEMORY_SP support is disabled. 14 */ 15 if (!efi_soft_reserve_enabled()) 16 return; 17 18 if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem) 19 return; 20 21 /* 22 * Given that efi_fake_memmap() needs to perform memblock 23 * allocations it needs to run after e820__memblock_setup(). 24 * However, if efi_fake_mem specifies EFI_MEMORY_SP for a given 25 * address range that potentially needs to mark the memory as 26 * reserved prior to e820__memblock_setup(). Update e820 27 * directly if EFI_MEMORY_SP is specified for an 28 * EFI_CONVENTIONAL_MEMORY descriptor. 29 */ 30 for (i = 0; i < nr_fake_mem; i++) { 31 struct efi_mem_range *mem = &efi_fake_mems[i]; 32 efi_memory_desc_t *md; 33 u64 m_start, m_end; 34 35 if ((mem->attribute & EFI_MEMORY_SP) == 0) 36 continue; 37 38 m_start = mem->range.start; 39 m_end = mem->range.end; 40 for_each_efi_memory_desc(md) { 41 u64 start, end, size; 42 43 if (md->type != EFI_CONVENTIONAL_MEMORY) 44 continue; 45 46 start = md->phys_addr; 47 end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1; 48 49 if (m_start <= end && m_end >= start) 50 /* fake range overlaps descriptor */; 51 else 52 continue; 53 54 /* 55 * Trim the boundary of the e820 update to the 56 * descriptor in case the fake range overlaps 57 * !EFI_CONVENTIONAL_MEMORY 58 */ 59 start = max(start, m_start); 60 end = min(end, m_end); 61 size = end - start + 1; 62 63 if (end <= start) 64 continue; 65 66 /* 67 * Ensure each efi_fake_mem instance results in 68 * a unique e820 resource 69 */ 70 e820__range_remove(start, size, E820_TYPE_RAM, 1); 71 e820__range_add(start, size, E820_TYPE_SOFT_RESERVED); 72 e820__update_table(e820_table); 73 } 74 } 75}