1 files changed, 196 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/elf.c b/tools/testing/selftests/kvm/lib/elf.c
new file mode 100644
index 000000000..bc75a91e0
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/elf.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * tools/testing/selftests/kvm/lib/elf.c
+ *
+ * Copyright (C) 2018, Google LLC.
+ */
+
+#include "test_util.h"
+
+#include <bits/endian.h>
+#include <linux/elf.h>
+
+#include "kvm_util.h"
+#include "kvm_util_internal.h"
+
+static void elfhdr_get(const char *filename, Elf64_Ehdr *hdrp)
+{
+	off_t offset_rv;
+
+	/* Open the ELF file. */
+	int fd;
+	fd = open(filename, O_RDONLY);
+	TEST_ASSERT(fd >= 0, "Failed to open ELF file,\n"
+		"  filename: %s\n"
+		"  rv: %i errno: %i", filename, fd, errno);
+
+	/* Read in and validate ELF Identification Record.
+	 * The ELF Identification record is the first 16 (EI_NIDENT) bytes
+	 * of the ELF header, which is at the beginning of the ELF file.
+	 * For now it is only safe to read the first EI_NIDENT bytes.  Once
+	 * read and validated, the value of e_ehsize can be used to determine
+	 * the real size of the ELF header.
+	 */
+	unsigned char ident[EI_NIDENT];
+	test_read(fd, ident, sizeof(ident));
+	TEST_ASSERT((ident[EI_MAG0] == ELFMAG0) && (ident[EI_MAG1] == ELFMAG1)
+		&& (ident[EI_MAG2] == ELFMAG2) && (ident[EI_MAG3] == ELFMAG3),
+		"ELF MAGIC Mismatch,\n"
+		"  filename: %s\n"
+		"  ident[EI_MAG0 - EI_MAG3]: %02x %02x %02x %02x\n"
+		"  Expected: %02x %02x %02x %02x",
+		filename,
+		ident[EI_MAG0], ident[EI_MAG1], ident[EI_MAG2], ident[EI_MAG3],
+		ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3);
+	TEST_ASSERT(ident[EI_CLASS] == ELFCLASS64,
+		"Current implementation only able to handle ELFCLASS64,\n"
+		"  filename: %s\n"
+		"  ident[EI_CLASS]: %02x\n"
+		"  expected: %02x",
+		filename,
+		ident[EI_CLASS], ELFCLASS64);
+	TEST_ASSERT(((BYTE_ORDER == LITTLE_ENDIAN)
+			&& (ident[EI_DATA] == ELFDATA2LSB))
+		|| ((BYTE_ORDER == BIG_ENDIAN)
+			&& (ident[EI_DATA] == ELFDATA2MSB)), "Current "
+		"implementation only able to handle\n"
+		"cases where the host and ELF file endianness\n"
+		"is the same:\n"
+		"  host BYTE_ORDER: %u\n"
+		"  host LITTLE_ENDIAN: %u\n"
+		"  host BIG_ENDIAN: %u\n"
+		"  ident[EI_DATA]: %u\n"
+		"  ELFDATA2LSB: %u\n"
+		"  ELFDATA2MSB: %u",
+		BYTE_ORDER, LITTLE_ENDIAN, BIG_ENDIAN,
+		ident[EI_DATA], ELFDATA2LSB, ELFDATA2MSB);
+	TEST_ASSERT(ident[EI_VERSION] == EV_CURRENT,
+		"Current implementation only able to handle current "
+		"ELF version,\n"
+		"  filename: %s\n"
+		"  ident[EI_VERSION]: %02x\n"
+		"  expected: %02x",
+		filename, ident[EI_VERSION], EV_CURRENT);
+
+	/* Read in the ELF header.
+	 * With the ELF Identification portion of the ELF header
+	 * validated, especially that the value at EI_VERSION is
+	 * as expected, it is now safe to read the entire ELF header.
+	 */
+	offset_rv = lseek(fd, 0, SEEK_SET);
+	TEST_ASSERT(offset_rv == 0, "Seek to ELF header failed,\n"
+		"  rv: %zi expected: %i", offset_rv, 0);
+	test_read(fd, hdrp, sizeof(*hdrp));
+	TEST_ASSERT(hdrp->e_phentsize == sizeof(Elf64_Phdr),
+		"Unexpected physical header size,\n"
+		"  hdrp->e_phentsize: %x\n"
+		"  expected: %zx",
+		hdrp->e_phentsize, sizeof(Elf64_Phdr));
+	TEST_ASSERT(hdrp->e_shentsize == sizeof(Elf64_Shdr),
+		"Unexpected section header size,\n"
+		"  hdrp->e_shentsize: %x\n"
+		"  expected: %zx",
+		hdrp->e_shentsize, sizeof(Elf64_Shdr));
+}
+
+/* VM ELF Load
+ *
+ * Input Args:
+ *   filename - Path to ELF file
+ *
+ * Output Args: None
+ *
+ * Input/Output Args:
+ *   vm - Pointer to opaque type that describes the VM.
+ *
+ * Return: None, TEST_ASSERT failures for all error conditions
+ *
+ * Loads the program image of the ELF file specified by filename,
+ * into the virtual address space of the VM pointed to by vm.  On entry
+ * the VM needs to not be using any of the virtual address space used
+ * by the image and it needs to have sufficient available physical pages, to
+ * back the virtual pages used to load the image.
+ */
+void kvm_vm_elf_load(struct kvm_vm *vm, const char *filename,
+	uint32_t data_memslot, uint32_t pgd_memslot)
+{
+	off_t offset, offset_rv;
+	Elf64_Ehdr hdr;
+
+	/* Open the ELF file. */
+	int fd;
+	fd = open(filename, O_RDONLY);
+	TEST_ASSERT(fd >= 0, "Failed to open ELF file,\n"
+		"  filename: %s\n"
+		"  rv: %i errno: %i", filename, fd, errno);
+
+	/* Read in the ELF header. */
+	elfhdr_get(filename, &hdr);
+
+	/* For each program header.
+	 * The following ELF header members specify the location
+	 * and size of the program headers:
+	 *
+	 *   e_phoff - File offset to start of program headers
+	 *   e_phentsize - Size of each program header
+	 *   e_phnum - Number of program header entries
+	 */
+	for (unsigned int n1 = 0; n1 < hdr.e_phnum; n1++) {
+		/* Seek to the beginning of the program header. */
+		offset = hdr.e_phoff + (n1 * hdr.e_phentsize);
+		offset_rv = lseek(fd, offset, SEEK_SET);
+		TEST_ASSERT(offset_rv == offset,
+			"Failed to seek to begining of program header %u,\n"
+			"  filename: %s\n"
+			"  rv: %jd errno: %i",
+			n1, filename, (intmax_t) offset_rv, errno);
+
+		/* Read in the program header. */
+		Elf64_Phdr phdr;
+		test_read(fd, &phdr, sizeof(phdr));
+
+		/* Skip if this header doesn't describe a loadable segment. */
+		if (phdr.p_type != PT_LOAD)
+			continue;
+
+		/* Allocate memory for this segment within the VM. */
+		TEST_ASSERT(phdr.p_memsz > 0, "Unexpected loadable segment "
+			"memsize of 0,\n"
+			"  phdr index: %u p_memsz: 0x%" PRIx64,
+			n1, (uint64_t) phdr.p_memsz);
+		vm_vaddr_t seg_vstart = phdr.p_vaddr;
+		seg_vstart &= ~(vm_vaddr_t)(vm->page_size - 1);
+		vm_vaddr_t seg_vend = phdr.p_vaddr + phdr.p_memsz - 1;
+		seg_vend |= vm->page_size - 1;
+		size_t seg_size = seg_vend - seg_vstart + 1;
+
+		vm_vaddr_t vaddr = vm_vaddr_alloc(vm, seg_size, seg_vstart,
+			data_memslot, pgd_memslot);
+		TEST_ASSERT(vaddr == seg_vstart, "Unable to allocate "
+			"virtual memory for segment at requested min addr,\n"
+			"  segment idx: %u\n"
+			"  seg_vstart: 0x%lx\n"
+			"  vaddr: 0x%lx",
+			n1, seg_vstart, vaddr);
+		memset(addr_gva2hva(vm, vaddr), 0, seg_size);
+		/* TODO(lhuemill): Set permissions of each memory segment
+		 * based on the least-significant 3 bits of phdr.p_flags.
+		 */
+
+		/* Load portion of initial state that is contained within
+		 * the ELF file.
+		 */
+		if (phdr.p_filesz) {
+			offset_rv = lseek(fd, phdr.p_offset, SEEK_SET);
+			TEST_ASSERT(offset_rv == phdr.p_offset,
+				"Seek to program segment offset failed,\n"
+				"  program header idx: %u errno: %i\n"
+				"  offset_rv: 0x%jx\n"
+				"  expected: 0x%jx\n",
+				n1, errno, (intmax_t) offset_rv,
+				(intmax_t) phdr.p_offset);
+			test_read(fd, addr_gva2hva(vm, phdr.p_vaddr),
+				phdr.p_filesz);
+		}
+	}
+}