1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * tools/testing/selftests/kvm/lib/elf.c 4 * 5 * Copyright (C) 2018, Google LLC. 6 */ 7 8 #include "test_util.h" 9 10 #include <bits/endian.h> 11 #include <linux/elf.h> 12 13 #include "kvm_util.h" 14 #include "kvm_util_internal.h" 15 16 static void elfhdr_get(const char *filename, Elf64_Ehdr *hdrp) 17 { 18 off_t offset_rv; 19 20 /* Open the ELF file. */ 21 int fd; 22 fd = open(filename, O_RDONLY); 23 TEST_ASSERT(fd >= 0, "Failed to open ELF file,\n" 24 " filename: %s\n" 25 " rv: %i errno: %i", filename, fd, errno); 26 27 /* Read in and validate ELF Identification Record. 28 * The ELF Identification record is the first 16 (EI_NIDENT) bytes 29 * of the ELF header, which is at the beginning of the ELF file. 30 * For now it is only safe to read the first EI_NIDENT bytes. Once 31 * read and validated, the value of e_ehsize can be used to determine 32 * the real size of the ELF header. 33 */ 34 unsigned char ident[EI_NIDENT]; 35 test_read(fd, ident, sizeof(ident)); 36 TEST_ASSERT((ident[EI_MAG0] == ELFMAG0) && (ident[EI_MAG1] == ELFMAG1) 37 && (ident[EI_MAG2] == ELFMAG2) && (ident[EI_MAG3] == ELFMAG3), 38 "ELF MAGIC Mismatch,\n" 39 " filename: %s\n" 40 " ident[EI_MAG0 - EI_MAG3]: %02x %02x %02x %02x\n" 41 " Expected: %02x %02x %02x %02x", 42 filename, 43 ident[EI_MAG0], ident[EI_MAG1], ident[EI_MAG2], ident[EI_MAG3], 44 ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3); 45 TEST_ASSERT(ident[EI_CLASS] == ELFCLASS64, 46 "Current implementation only able to handle ELFCLASS64,\n" 47 " filename: %s\n" 48 " ident[EI_CLASS]: %02x\n" 49 " expected: %02x", 50 filename, 51 ident[EI_CLASS], ELFCLASS64); 52 TEST_ASSERT(((BYTE_ORDER == LITTLE_ENDIAN) 53 && (ident[EI_DATA] == ELFDATA2LSB)) 54 || ((BYTE_ORDER == BIG_ENDIAN) 55 && (ident[EI_DATA] == ELFDATA2MSB)), "Current " 56 "implementation only able to handle\n" 57 "cases where the host and ELF file endianness\n" 58 "is the same:\n" 59 " host BYTE_ORDER: %u\n" 60 " host LITTLE_ENDIAN: %u\n" 61 " host BIG_ENDIAN: %u\n" 62 " ident[EI_DATA]: %u\n" 63 " ELFDATA2LSB: %u\n" 64 " ELFDATA2MSB: %u", 65 BYTE_ORDER, LITTLE_ENDIAN, BIG_ENDIAN, 66 ident[EI_DATA], ELFDATA2LSB, ELFDATA2MSB); 67 TEST_ASSERT(ident[EI_VERSION] == EV_CURRENT, 68 "Current implementation only able to handle current " 69 "ELF version,\n" 70 " filename: %s\n" 71 " ident[EI_VERSION]: %02x\n" 72 " expected: %02x", 73 filename, ident[EI_VERSION], EV_CURRENT); 74 75 /* Read in the ELF header. 76 * With the ELF Identification portion of the ELF header 77 * validated, especially that the value at EI_VERSION is 78 * as expected, it is now safe to read the entire ELF header. 79 */ 80 offset_rv = lseek(fd, 0, SEEK_SET); 81 TEST_ASSERT(offset_rv == 0, "Seek to ELF header failed,\n" 82 " rv: %zi expected: %i", offset_rv, 0); 83 test_read(fd, hdrp, sizeof(*hdrp)); 84 TEST_ASSERT(hdrp->e_phentsize == sizeof(Elf64_Phdr), 85 "Unexpected physical header size,\n" 86 " hdrp->e_phentsize: %x\n" 87 " expected: %zx", 88 hdrp->e_phentsize, sizeof(Elf64_Phdr)); 89 TEST_ASSERT(hdrp->e_shentsize == sizeof(Elf64_Shdr), 90 "Unexpected section header size,\n" 91 " hdrp->e_shentsize: %x\n" 92 " expected: %zx", 93 hdrp->e_shentsize, sizeof(Elf64_Shdr)); 94 } 95 96 /* VM ELF Load 97 * 98 * Input Args: 99 * filename - Path to ELF file 100 * 101 * Output Args: None 102 * 103 * Input/Output Args: 104 * vm - Pointer to opaque type that describes the VM. 105 * 106 * Return: None, TEST_ASSERT failures for all error conditions 107 * 108 * Loads the program image of the ELF file specified by filename, 109 * into the virtual address space of the VM pointed to by vm. On entry 110 * the VM needs to not be using any of the virtual address space used 111 * by the image and it needs to have sufficient available physical pages, to 112 * back the virtual pages used to load the image. 113 */ 114 void kvm_vm_elf_load(struct kvm_vm *vm, const char *filename, 115 uint32_t data_memslot, uint32_t pgd_memslot) 116 { 117 off_t offset, offset_rv; 118 Elf64_Ehdr hdr; 119 120 /* Open the ELF file. */ 121 int fd; 122 fd = open(filename, O_RDONLY); 123 TEST_ASSERT(fd >= 0, "Failed to open ELF file,\n" 124 " filename: %s\n" 125 " rv: %i errno: %i", filename, fd, errno); 126 127 /* Read in the ELF header. */ 128 elfhdr_get(filename, &hdr); 129 130 /* For each program header. 131 * The following ELF header members specify the location 132 * and size of the program headers: 133 * 134 * e_phoff - File offset to start of program headers 135 * e_phentsize - Size of each program header 136 * e_phnum - Number of program header entries 137 */ 138 for (unsigned int n1 = 0; n1 < hdr.e_phnum; n1++) { 139 /* Seek to the beginning of the program header. */ 140 offset = hdr.e_phoff + (n1 * hdr.e_phentsize); 141 offset_rv = lseek(fd, offset, SEEK_SET); 142 TEST_ASSERT(offset_rv == offset, 143 "Failed to seek to begining of program header %u,\n" 144 " filename: %s\n" 145 " rv: %jd errno: %i", 146 n1, filename, (intmax_t) offset_rv, errno); 147 148 /* Read in the program header. */ 149 Elf64_Phdr phdr; 150 test_read(fd, &phdr, sizeof(phdr)); 151 152 /* Skip if this header doesn't describe a loadable segment. */ 153 if (phdr.p_type != PT_LOAD) 154 continue; 155 156 /* Allocate memory for this segment within the VM. */ 157 TEST_ASSERT(phdr.p_memsz > 0, "Unexpected loadable segment " 158 "memsize of 0,\n" 159 " phdr index: %u p_memsz: 0x%" PRIx64, 160 n1, (uint64_t) phdr.p_memsz); 161 vm_vaddr_t seg_vstart = phdr.p_vaddr; 162 seg_vstart &= ~(vm_vaddr_t)(vm->page_size - 1); 163 vm_vaddr_t seg_vend = phdr.p_vaddr + phdr.p_memsz - 1; 164 seg_vend |= vm->page_size - 1; 165 size_t seg_size = seg_vend - seg_vstart + 1; 166 167 vm_vaddr_t vaddr = vm_vaddr_alloc(vm, seg_size, seg_vstart, 168 data_memslot, pgd_memslot); 169 TEST_ASSERT(vaddr == seg_vstart, "Unable to allocate " 170 "virtual memory for segment at requested min addr,\n" 171 " segment idx: %u\n" 172 " seg_vstart: 0x%lx\n" 173 " vaddr: 0x%lx", 174 n1, seg_vstart, vaddr); 175 memset(addr_gva2hva(vm, vaddr), 0, seg_size); 176 /* TODO(lhuemill): Set permissions of each memory segment 177 * based on the least-significant 3 bits of phdr.p_flags. 178 */ 179 180 /* Load portion of initial state that is contained within 181 * the ELF file. 182 */ 183 if (phdr.p_filesz) { 184 offset_rv = lseek(fd, phdr.p_offset, SEEK_SET); 185 TEST_ASSERT(offset_rv == phdr.p_offset, 186 "Seek to program segment offset failed,\n" 187 " program header idx: %u errno: %i\n" 188 " offset_rv: 0x%jx\n" 189 " expected: 0x%jx\n", 190 n1, errno, (intmax_t) offset_rv, 191 (intmax_t) phdr.p_offset); 192 test_read(fd, addr_gva2hva(vm, phdr.p_vaddr), 193 phdr.p_filesz); 194 } 195 } 196 } 197