diff options
Diffstat (limited to 'tests/tcg/plugins/patch.c')
| -rw-r--r-- | tests/tcg/plugins/patch.c | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/tests/tcg/plugins/patch.c b/tests/tcg/plugins/patch.c new file mode 100644 index 0000000..111c5c1 --- /dev/null +++ b/tests/tcg/plugins/patch.c @@ -0,0 +1,251 @@ +/* + * SPDX-License-Identifier: GPL-2.0-or-later + * + * This plugin patches instructions matching a pattern to a different + * instruction as they execute + * + */ + +#include "glib.h" +#include "glibconfig.h" + +#include <qemu-plugin.h> +#include <string.h> +#include <stdio.h> + +QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION; + +static bool use_hwaddr; +static GByteArray *target_data; +static GByteArray *patch_data; + +/** + * Parse a string of hexadecimal digits into a GByteArray. The string must be + * even length + */ +static GByteArray *str_to_bytes(const char *str) +{ + size_t len = strlen(str); + + if (len == 0 || len % 2 != 0) { + return NULL; + } + + GByteArray *bytes = g_byte_array_new(); + char byte[3] = {0}; + guint8 value = 0; + + for (size_t i = 0; i < len; i += 2) { + byte[0] = str[i]; + byte[1] = str[i + 1]; + value = (guint8)g_ascii_strtoull(byte, NULL, 16); + g_byte_array_append(bytes, &value, 1); + } + + return bytes; +} + +static void patch_hwaddr(unsigned int vcpu_index, void *userdata) +{ + uintptr_t addr = (uintptr_t) userdata; + g_autoptr(GString) str = g_string_new(NULL); + g_string_printf(str, "patching: @0x%" + PRIxPTR "\n", + addr); + qemu_plugin_outs(str->str); + + enum qemu_plugin_hwaddr_operation_result result = + qemu_plugin_write_memory_hwaddr(addr, patch_data); + + + if (result != QEMU_PLUGIN_HWADDR_OPERATION_OK) { + g_autoptr(GString) errmsg = g_string_new(NULL); + g_string_printf(errmsg, "Failed to write memory: %d\n", result); + qemu_plugin_outs(errmsg->str); + return; + } + + GByteArray *read_data = g_byte_array_new(); + + result = qemu_plugin_read_memory_hwaddr(addr, read_data, + patch_data->len); + + qemu_plugin_outs("Reading memory...\n"); + + if (result != QEMU_PLUGIN_HWADDR_OPERATION_OK) { + g_autoptr(GString) errmsg = g_string_new(NULL); + g_string_printf(errmsg, "Failed to read memory: %d\n", result); + qemu_plugin_outs(errmsg->str); + return; + } + + if (memcmp(patch_data->data, read_data->data, patch_data->len) != 0) { + qemu_plugin_outs("Failed to read back written data\n"); + } + + qemu_plugin_outs("Success!\n"); + + return; +} + +static void patch_vaddr(unsigned int vcpu_index, void *userdata) +{ + uintptr_t addr = (uintptr_t) userdata; + uint64_t hwaddr = 0; + if (!qemu_plugin_translate_vaddr(addr, &hwaddr)) { + qemu_plugin_outs("Failed to translate vaddr\n"); + return; + } + g_autoptr(GString) str = g_string_new(NULL); + g_string_printf(str, "patching: @0x%" + PRIxPTR " hw: @0x%" PRIx64 "\n", + addr, hwaddr); + qemu_plugin_outs(str->str); + + qemu_plugin_outs("Writing memory (vaddr)...\n"); + + if (!qemu_plugin_write_memory_vaddr(addr, patch_data)) { + qemu_plugin_outs("Failed to write memory\n"); + return; + } + + qemu_plugin_outs("Reading memory (vaddr)...\n"); + + g_autoptr(GByteArray) read_data = g_byte_array_new(); + + if (!qemu_plugin_read_memory_vaddr(addr, read_data, patch_data->len)) { + qemu_plugin_outs("Failed to read memory\n"); + return; + } + + if (memcmp(patch_data->data, read_data->data, patch_data->len) != 0) { + qemu_plugin_outs("Failed to read back written data\n"); + } + + qemu_plugin_outs("Success!\n"); + + return; +} + +/* + * Callback on translation of a translation block. + */ +static void vcpu_tb_trans_cb(qemu_plugin_id_t id, struct qemu_plugin_tb *tb) +{ + g_autoptr(GByteArray) insn_data = g_byte_array_new(); + uintptr_t addr = 0; + + for (size_t i = 0; i < qemu_plugin_tb_n_insns(tb); i++) { + struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i); + uint64_t vaddr = qemu_plugin_insn_vaddr(insn); + + if (use_hwaddr) { + uint64_t hwaddr = 0; + if (!qemu_plugin_translate_vaddr(vaddr, &hwaddr)) { + qemu_plugin_outs("Failed to translate vaddr\n"); + continue; + } + /* + * As we cannot emulate 64 bit systems on 32 bit hosts we + * should never see the top bits set, hence we can safely + * cast to uintptr_t. + */ + g_assert(hwaddr <= UINTPTR_MAX); + addr = (uintptr_t) hwaddr; + } else { + g_assert(vaddr <= UINTPTR_MAX); + addr = (uintptr_t) vaddr; + } + + g_byte_array_set_size(insn_data, qemu_plugin_insn_size(insn)); + qemu_plugin_insn_data(insn, insn_data->data, insn_data->len); + + if (insn_data->len >= target_data->len && + !memcmp(insn_data->data, target_data->data, + MIN(target_data->len, insn_data->len))) { + if (use_hwaddr) { + qemu_plugin_register_vcpu_tb_exec_cb(tb, patch_hwaddr, + QEMU_PLUGIN_CB_NO_REGS, + (void *) addr); + } else { + qemu_plugin_register_vcpu_tb_exec_cb(tb, patch_vaddr, + QEMU_PLUGIN_CB_NO_REGS, + (void *) addr); + } + } + } +} + +static void usage(void) +{ + fprintf(stderr, "Usage: <lib>,target=<bytes>,patch=<new_bytes>" + "[,use_hwaddr=true|false]"); +} + +/* + * Called when the plugin is installed + */ +QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id, + const qemu_info_t *info, int argc, + char **argv) +{ + + use_hwaddr = true; + target_data = NULL; + patch_data = NULL; + + if (argc > 4) { + usage(); + return -1; + } + + for (size_t i = 0; i < argc; i++) { + char *opt = argv[i]; + g_auto(GStrv) tokens = g_strsplit(opt, "=", 2); + if (g_strcmp0(tokens[0], "use_hwaddr") == 0) { + if (!qemu_plugin_bool_parse(tokens[0], tokens[1], &use_hwaddr)) { + fprintf(stderr, + "Failed to parse boolean argument use_hwaddr\n"); + return -1; + } + } else if (g_strcmp0(tokens[0], "target") == 0) { + target_data = str_to_bytes(tokens[1]); + if (!target_data) { + fprintf(stderr, + "Failed to parse target bytes.\n"); + return -1; + } + } else if (g_strcmp0(tokens[0], "patch") == 0) { + patch_data = str_to_bytes(tokens[1]); + if (!patch_data) { + fprintf(stderr, "Failed to parse patch bytes.\n"); + return -1; + } + } else { + fprintf(stderr, "Unknown argument: %s\n", tokens[0]); + usage(); + return -1; + } + } + + if (!target_data) { + fprintf(stderr, "target argument is required\n"); + usage(); + return -1; + } + + if (!patch_data) { + fprintf(stderr, "patch argument is required\n"); + usage(); + return -1; + } + + if (target_data->len != patch_data->len) { + fprintf(stderr, "Target and patch data must be the same length\n"); + return -1; + } + + qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans_cb); + + return 0; +} |