From b7855bf65f5bed868b06d6492a6d8a174f6cb71b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Thu, 29 Sep 2022 12:42:15 +0100 Subject: [PATCH] plugins: extend execlog to filter matches MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sometimes the whole execlog is just two much so add the ability to filter by instruction opcode or address. [AJB: this shows for example qemu-system-aarch64 -display none -serial mon:stdio \ -M virt -cpu max \ -semihosting-config enable=on \ -kernel ./tests/tcg/aarch64-softmmu/memory-sve \ -plugin ./contrib/plugins/libexeclog.so,ifilter=st1w,afilter=0x40001808 -d plugin -D plugin.out the st1w SVE instruction is not instrumenting its stores.] Signed-off-by: Alex Bennée Reviewed-by: Alexandre Iooss Cc: Robert Henry Cc: Aaron Lindsay Message-Id: <20220929114231.583801-36-alex.bennee@linaro.org> --- contrib/plugins/execlog.c | 96 ++++++++++++++++++++++++++++++++------ docs/devel/tcg-plugins.rst | 9 +++- 2 files changed, 90 insertions(+), 15 deletions(-) diff --git a/contrib/plugins/execlog.c b/contrib/plugins/execlog.c index a5275dcc15..e659ac9cbb 100644 --- a/contrib/plugins/execlog.c +++ b/contrib/plugins/execlog.c @@ -20,6 +20,9 @@ QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION; /* Store last executed instruction on each vCPU as a GString */ GArray *last_exec; +static GPtrArray *imatches; +static GArray *amatches; + /** * Add memory read or write information to current instruction log */ @@ -85,12 +88,13 @@ static void vcpu_insn_exec(unsigned int cpu_index, void *udata) static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb) { struct qemu_plugin_insn *insn; - uint64_t insn_vaddr; - uint32_t insn_opcode; - char *insn_disas; + bool skip = (imatches || amatches) ? true : false; size_t n = qemu_plugin_tb_n_insns(tb); for (size_t i = 0; i < n; i++) { + char *insn_disas; + uint64_t insn_vaddr; + /* * `insn` is shared between translations in QEMU, copy needed data here. * `output` is never freed as it might be used multiple times during @@ -99,20 +103,52 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb) * a limitation for CISC architectures. */ insn = qemu_plugin_tb_get_insn(tb, i); - insn_vaddr = qemu_plugin_insn_vaddr(insn); - insn_opcode = *((uint32_t *)qemu_plugin_insn_data(insn)); insn_disas = qemu_plugin_insn_disas(insn); - char *output = g_strdup_printf("0x%"PRIx64", 0x%"PRIx32", \"%s\"", - insn_vaddr, insn_opcode, insn_disas); + insn_vaddr = qemu_plugin_insn_vaddr(insn); - /* Register callback on memory read or write */ - qemu_plugin_register_vcpu_mem_cb(insn, vcpu_mem, - QEMU_PLUGIN_CB_NO_REGS, - QEMU_PLUGIN_MEM_RW, NULL); + /* + * If we are filtering we better check out if we have any + * hits. The skip "latches" so we can track memory accesses + * after the instruction we care about. + */ + if (skip && imatches) { + int j; + for (j = 0; j < imatches->len && skip; j++) { + char *m = g_ptr_array_index(imatches, j); + if (g_str_has_prefix(insn_disas, m)) { + skip = false; + } + } + } + + if (skip && amatches) { + int j; + for (j = 0; j < amatches->len && skip; j++) { + uint64_t v = g_array_index(amatches, uint64_t, j); + if (v == insn_vaddr) { + skip = false; + } + } + } + + if (skip) { + g_free(insn_disas); + } else { + uint32_t insn_opcode; + insn_opcode = *((uint32_t *)qemu_plugin_insn_data(insn)); + char *output = g_strdup_printf("0x%"PRIx64", 0x%"PRIx32", \"%s\"", + insn_vaddr, insn_opcode, insn_disas); + + /* Register callback on memory read or write */ + qemu_plugin_register_vcpu_mem_cb(insn, vcpu_mem, + QEMU_PLUGIN_CB_NO_REGS, + QEMU_PLUGIN_MEM_RW, NULL); + + /* Register callback on instruction */ + qemu_plugin_register_vcpu_insn_exec_cb(insn, vcpu_insn_exec, + QEMU_PLUGIN_CB_NO_REGS, output); + } - /* Register callback on instruction */ - qemu_plugin_register_vcpu_insn_exec_cb(insn, vcpu_insn_exec, - QEMU_PLUGIN_CB_NO_REGS, output); } } @@ -132,6 +168,25 @@ static void plugin_exit(qemu_plugin_id_t id, void *p) } } +/* Add a match to the array of matches */ +static void parse_insn_match(char *match) +{ + if (!imatches) { + imatches = g_ptr_array_new(); + } + g_ptr_array_add(imatches, match); +} + +static void parse_vaddr_match(char *match) +{ + uint64_t v = g_ascii_strtoull(match, NULL, 16); + + if (!amatches) { + amatches = g_array_new(false, true, sizeof(uint64_t)); + } + g_array_append_val(amatches, v); +} + /** * Install the plugin */ @@ -145,6 +200,19 @@ QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id, */ last_exec = g_array_new(FALSE, FALSE, sizeof(GString *)); + for (int i = 0; i < argc; i++) { + char *opt = argv[i]; + g_autofree char **tokens = g_strsplit(opt, "=", 2); + if (g_strcmp0(tokens[0], "ifilter") == 0) { + parse_insn_match(tokens[1]); + } else if (g_strcmp0(tokens[0], "afilter") == 0) { + parse_vaddr_match(tokens[1]); + } else { + fprintf(stderr, "option parsing failed: %s\n", opt); + return -1; + } + } + /* Register translation block and exit callbacks */ qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans); qemu_plugin_register_atexit_cb(id, plugin_exit, NULL); diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst index a7cc44aa20..a503d44cee 100644 --- a/docs/devel/tcg-plugins.rst +++ b/docs/devel/tcg-plugins.rst @@ -346,7 +346,7 @@ The execlog tool traces executed instructions with memory access. It can be used for debugging and security analysis purposes. Please be aware that this will generate a lot of output. -The plugin takes no argument:: +The plugin needs default argument:: qemu-system-arm $(QEMU_ARGS) \ -plugin ./contrib/plugins/libexeclog.so -d plugin @@ -364,6 +364,13 @@ which will output an execution trace following this structure:: 0, 0xd34, 0xf9c8f000, "bl #0x10c8" 0, 0x10c8, 0xfff96c43, "ldr r3, [r0, #0x44]", load, 0x200000e4, RAM +the output can be filtered to only track certain instructions or +addresses using the `ifilter` or `afilter` options. You can stack the +arguments if required:: + + qemu-system-arm $(QEMU_ARGS) \ + -plugin ./contrib/plugins/libexeclog.so,ifilter=st1w,afilter=0x40001808 -d plugin + - contrib/plugins/cache.c Cache modelling plugin that measures the performance of a given L1 cache