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Iglesias" , John Snow , Aurelien Jarno , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Yanan Wang , Eduardo Habkost , Brian Cain , Laurent Vivier , Palmer Dabbelt , Cleber Rosa , David Hildenbrand , Beraldo Leal , Pierrick Bouvier , Weiwei Li , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Paul Durrant , qemu-s390x@nongnu.org, David Woodhouse , Liu Zhiwei , Ilya Leoshkevich , Wainer dos Santos Moschetta , Michael Rolnik , Alistair Francis , Daniel Henrique Barboza , Laurent Vivier , kvm@vger.kernel.org, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Alexandre Iooss , Thomas Huth , Peter Maydell , qemu-ppc@nongnu.org, Paolo Bonzini , Marcel Apfelbaum , Nicholas Piggin , qemu-riscv@nongnu.org, qemu-arm@nongnu.org, Song Gao , Yoshinori Sato , Richard Henderson , Daniel Henrique Barboza , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Mahmoud Mandour , Bin Meng , Akihiko Odaki Subject: [PATCH 39/40] contrib/plugins: extend execlog to track register changes Date: Thu, 21 Dec 2023 10:38:17 +0000 Message-Id: <20231221103818.1633766-40-alex.bennee@linaro.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231221103818.1633766-1-alex.bennee@linaro.org> References: <20231221103818.1633766-1-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::429; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x429.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @linaro.org) X-ZM-MESSAGEID: 1703155503634100007 With the new plugin register API we can now track changes to register values. Currently the implementation is fairly dumb which will slow down if a large number of register values are being tracked. This could be improved by only instrumenting instructions which mention registers we are interested in tracking. Example usage: ./qemu-aarch64 -D plugin.log -d plugin \ -cpu max,sve256=3Don \ -plugin contrib/plugins/libexeclog.so,reg=3Dsp,reg=3Dz\* \ ./tests/tcg/aarch64-linux-user/sha512-sve will display in the execlog any changes to the stack pointer (sp) and the SVE Z registers. Signed-off-by: Alex Benn=C3=A9e Cc: Akihiko Odaki Based-On: <20231025093128.33116-19-akihiko.odaki@daynix.com> --- v2 - we now do the glob-like search in the plugin itself. - fix some erroneous cpus->cpu vAJB: Changes for the new API with a simpler glob based "reg" specifier which can be specified multiple times. --- docs/devel/tcg-plugins.rst | 9 +- contrib/plugins/execlog.c | 189 ++++++++++++++++++++++++++++--------- 2 files changed, 153 insertions(+), 45 deletions(-) diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst index 81dcd43a612..3a0962723d7 100644 --- a/docs/devel/tcg-plugins.rst +++ b/docs/devel/tcg-plugins.rst @@ -497,6 +497,14 @@ arguments if required:: $ qemu-system-arm $(QEMU_ARGS) \ -plugin ./contrib/plugins/libexeclog.so,ifilter=3Dst1w,afilter=3D0x400= 01808 -d plugin =20 +This plugin can also dump registers when they change value. Specify the na= me of the +registers with multiple ``reg`` options. You can also use glob style match= ing if you wish:: + + $ qemu-system-arm $(QEMU_ARGS) \ + -plugin ./contrib/plugins/libexeclog.so,reg=3D\*_el2,reg=3Dsp -d plugin + +Be aware that each additional register to check will slow down execution q= uite considerably. + - contrib/plugins/cache.c =20 Cache modelling plugin that measures the performance of a given L1 cache @@ -583,4 +591,3 @@ The following API is generated from the inline document= ation in include the full kernel-doc annotations. =20 .. kernel-doc:: include/qemu/qemu-plugin.h - diff --git a/contrib/plugins/execlog.c b/contrib/plugins/execlog.c index f262e5555eb..74fbf7c0e60 100644 --- a/contrib/plugins/execlog.c +++ b/contrib/plugins/execlog.c @@ -1,7 +1,7 @@ /* * Copyright (C) 2021, Alexandre Iooss * - * Log instruction execution with memory access. + * Log instruction execution with memory access and register changes * * License: GNU GPL, version 2 or later. * See the COPYING file in the top-level directory. @@ -15,30 +15,29 @@ =20 #include =20 +typedef struct { + struct qemu_plugin_register *handle; + GByteArray *last; + GByteArray *new; + const char *name; +} Register; + +typedef struct CPU { + /* Store last executed instruction on each vCPU as a GString */ + GString *last_exec; + /* Ptr array of Register */ + GPtrArray *registers; +} CPU; + QEMU_PLUGIN_EXPORT int qemu_plugin_version =3D QEMU_PLUGIN_VERSION; =20 -/* Store last executed instruction on each vCPU as a GString */ -static GPtrArray *last_exec; +static CPU *cpus; +static int num_cpus; static GRWLock expand_array_lock; =20 static GPtrArray *imatches; static GArray *amatches; - -/* - * Expand last_exec array. - * - * As we could have multiple threads trying to do this we need to - * serialise the expansion under a lock. - */ -static void expand_last_exec(int cpu_index) -{ - g_rw_lock_writer_lock(&expand_array_lock); - while (cpu_index >=3D last_exec->len) { - GString *s =3D g_string_new(NULL); - g_ptr_array_add(last_exec, s); - } - g_rw_lock_writer_unlock(&expand_array_lock); -} +static GPtrArray *rmatches; =20 /** * Add memory read or write information to current instruction log @@ -50,8 +49,8 @@ static void vcpu_mem(unsigned int cpu_index, qemu_plugin_= meminfo_t info, =20 /* Find vCPU in array */ g_rw_lock_reader_lock(&expand_array_lock); - g_assert(cpu_index < last_exec->len); - s =3D g_ptr_array_index(last_exec, cpu_index); + g_assert(cpu_index < num_cpus); + s =3D cpus[cpu_index].last_exec; g_rw_lock_reader_unlock(&expand_array_lock); =20 /* Indicate type of memory access */ @@ -77,28 +76,46 @@ static void vcpu_mem(unsigned int cpu_index, qemu_plugi= n_meminfo_t info, */ static void vcpu_insn_exec(unsigned int cpu_index, void *udata) { - GString *s; + CPU *cpu; =20 - /* Find or create vCPU in array */ g_rw_lock_reader_lock(&expand_array_lock); - if (cpu_index >=3D last_exec->len) { - g_rw_lock_reader_unlock(&expand_array_lock); - expand_last_exec(cpu_index); - g_rw_lock_reader_lock(&expand_array_lock); - } - s =3D g_ptr_array_index(last_exec, cpu_index); + g_assert(cpu_index < num_cpus); + cpu =3D &cpus[cpu_index]; g_rw_lock_reader_unlock(&expand_array_lock); =20 /* Print previous instruction in cache */ - if (s->len) { - qemu_plugin_outs(s->str); + if (cpu->last_exec->len) { + if (cpu->registers) { + for (int n =3D 0; n < cpu->registers->len; n++) { + Register *reg =3D cpu->registers->pdata[n]; + int sz; + + g_byte_array_set_size(reg->new, 0); + sz =3D qemu_plugin_read_register(cpu_index, reg->handle, r= eg->new); + g_assert(sz =3D=3D reg->last->len); + + if (memcmp(reg->last->data, reg->new->data, sz)) { + GByteArray *temp =3D reg->last; + g_string_append_printf(cpu->last_exec, ", %s -> ", reg= ->name); + /* TODO: handle BE properly */ + for (int i =3D sz; i >=3D 0; i--) { + g_string_append_printf(cpu->last_exec, "%02x", + reg->new->data[i]); + } + reg->last =3D reg->new; + reg->new =3D temp; + } + } + } + + qemu_plugin_outs(cpu->last_exec->str); qemu_plugin_outs("\n"); } =20 /* Store new instruction in cache */ /* vcpu_mem will add memory access information to last_exec */ - g_string_printf(s, "%u, ", cpu_index); - g_string_append(s, (char *)udata); + g_string_printf(cpus[cpu_index].last_exec, "%u, ", cpu_index); + g_string_append(cpus[cpu_index].last_exec, (char *)udata); } =20 /** @@ -167,8 +184,10 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct = qemu_plugin_tb *tb) QEMU_PLUGIN_MEM_RW, NULL); =20 /* Register callback on instruction */ - qemu_plugin_register_vcpu_insn_exec_cb(insn, vcpu_insn_exec, - QEMU_PLUGIN_CB_NO_REGS,= output); + qemu_plugin_register_vcpu_insn_exec_cb( + insn, vcpu_insn_exec, + rmatches ? QEMU_PLUGIN_CB_R_REGS : QEMU_PLUGIN_CB_NO_REGS, + output); =20 /* reset skip */ skip =3D (imatches || amatches); @@ -177,17 +196,86 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct= qemu_plugin_tb *tb) } } =20 +static Register *init_vcpu_register(int vcpu_index, + qemu_plugin_reg_descriptor *desc) +{ + Register *reg =3D g_new0(Register, 1); + int r; + + reg->handle =3D desc->handle; + reg->name =3D g_strdup(desc->name); + reg->last =3D g_byte_array_new(); + reg->new =3D g_byte_array_new(); + + /* read the initial value */ + r =3D qemu_plugin_read_register(vcpu_index, reg->handle, reg->last); + g_assert(r > 0); + return reg; +} + +static registers_init(int vcpu_index) +{ + GPtrArray *registers =3D g_ptr_array_new(); + g_autoptr(GArray) reg_list =3D qemu_plugin_get_registers(vcpu_index); + + if (reg_list && reg_list->len) { + /* + * Go through each register in the complete list and + * see if we want to track it. + */ + for (int r =3D 0; r < reg_list->len; r++) { + qemu_plugin_reg_descriptor *rd =3D &g_array_index( + reg_list, qemu_plugin_reg_descriptor, r); + for (int p =3D 0; p < rmatches->len; p++) { + g_autoptr(GPatternSpec) pat =3D g_pattern_spec_new(rmatche= s->pdata[p]); + if (g_pattern_match_string(pat, rd->name)) { + Register *reg =3D init_vcpu_register(vcpu_index, rd); + g_ptr_array_add(registers, reg); + } + } + } + } + cpus[num_cpus].registers =3D registers; +} + +/* + * Initialise a new vcpu/thread with: + * - last_exec tracking data + * - list of tracked registers + * - initial value of registers + * + * As we could have multiple threads trying to do this we need to + * serialise the expansion under a lock. + */ +static void vcpu_init(qemu_plugin_id_t id, unsigned int vcpu_index) +{ + g_rw_lock_writer_lock(&expand_array_lock); + + if (vcpu_index >=3D num_cpus) { + cpus =3D g_realloc_n(cpus, vcpu_index + 1, sizeof(*cpus)); + while (vcpu_index >=3D num_cpus) { + cpus[num_cpus].last_exec =3D g_string_new(NULL); + + /* Any registers to track? */ + if (rmatches && rmatches->len) { + registers_init(vcpu_index); + } + num_cpus++; + } + } + + g_rw_lock_writer_unlock(&expand_array_lock); +} + /** * On plugin exit, print last instruction in cache */ static void plugin_exit(qemu_plugin_id_t id, void *p) { guint i; - GString *s; - for (i =3D 0; i < last_exec->len; i++) { - s =3D g_ptr_array_index(last_exec, i); - if (s->str) { - qemu_plugin_outs(s->str); + for (i =3D 0; i < num_cpus; i++) { + if (cpus[i].last_exec->str) { + qemu_plugin_outs(cpus[i].last_exec->str); qemu_plugin_outs("\n"); } } @@ -212,6 +300,18 @@ static void parse_vaddr_match(char *match) g_array_append_val(amatches, v); } =20 +/* + * We have to wait until vCPUs are started before we can check the + * patterns find anything. + */ +static void add_regpat(char *regpat) +{ + if (!rmatches) { + rmatches =3D g_ptr_array_new(); + } + g_ptr_array_add(rmatches, g_strdup(regpat)); +} + /** * Install the plugin */ @@ -224,9 +324,7 @@ QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_= id_t id, * we don't know the size before emulation. */ if (info->system_emulation) { - last_exec =3D g_ptr_array_sized_new(info->system.max_vcpus); - } else { - last_exec =3D g_ptr_array_new(); + cpus =3D g_new(CPU, info->system.max_vcpus); } =20 for (int i =3D 0; i < argc; i++) { @@ -236,13 +334,16 @@ QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugi= n_id_t id, parse_insn_match(tokens[1]); } else if (g_strcmp0(tokens[0], "afilter") =3D=3D 0) { parse_vaddr_match(tokens[1]); + } else if (g_strcmp0(tokens[0], "reg") =3D=3D 0) { + add_regpat(tokens[1]); } else { fprintf(stderr, "option parsing failed: %s\n", opt); return -1; } } =20 - /* Register translation block and exit callbacks */ + /* Register init, translation block and exit callbacks */ + qemu_plugin_register_vcpu_init_cb(id, vcpu_init); qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans); qemu_plugin_register_atexit_cb(id, plugin_exit, NULL); =20 --=20 2.39.2