Override kvm_emulate_insn formatting to use a disassembler to format
the emulated instruction. If a disassembler (udis86) is not available,
fall back to showing the instruction bytes in hex.
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
---
Note 1: on top of 'master' with 'trace-cmd-kvm' cherry-picked on top.
Note 2: I get output of the form
... kvm_emulate_insn: 0:fffff800010527b5: mov $0x0, 0xfffe00b0CAN'T FIND FIELD "guest_rip"
which leads me to believe there is a bug in trace_seq_printf when the input
to %s is "".
Makefile | 11 +++++-
plugin_kvm.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 121 insertions(+), 1 deletions(-)
diff --git a/Makefile b/Makefile
index 5282f94..fe34d1c 100644
--- a/Makefile
+++ b/Makefile
@@ -74,6 +74,14 @@ ifeq ($(shell sh -c "python-config --includes > /dev/null 2>&1 && echo y"), y)
PYTHON_PY_INSTALL := event-viewer.install tracecmd.install tracecmdgui.install
endif
+# $(call test-build, snippet, ret) -> ret if snippet compiles
+# -> empty otherwise
+test-build = $(if $(shell $(CC) -o /dev/null -c -x c - > /dev/null 2>&1 \
+ <<<'$1' && echo y), $2)
+
+# have udis86 disassembler library?
+udis86-flags := $(call test-build,\#include <udis86.h>,-DHAVE_UDIS86 -ludis86)
+
ifeq ("$(origin O)", "command line")
BUILD_OUTPUT := $(O)
endif
@@ -188,6 +196,7 @@ CFLAGS ?= -g -Wall
# Append required CFLAGS
override CFLAGS += $(CONFIG_FLAGS) $(INCLUDES) $(PLUGIN_DIR_SQ)
+override CFLAGS += $(udis86-flags)
ifeq ($(VERBOSE),1)
Q =
@@ -228,7 +237,7 @@ do_compile_plugin_obj = \
do_plugin_build = \
($(print_plugin_build) \
- $(CC) -shared -nostartfiles -o $@ $<)
+ $(CC) $(CFLAGS) -shared -nostartfiles -o $@ $<)
do_build_static_lib = \
($(print_static_lib_build) \
diff --git a/plugin_kvm.c b/plugin_kvm.c
index 7217e85..00cac5a 100644
--- a/plugin_kvm.c
+++ b/plugin_kvm.c
@@ -21,9 +21,68 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <stdint.h>
#include "parse-events.h"
+#ifdef HAVE_UDIS86
+
+#include <udis86.h>
+
+static ud_t ud;
+
+static void init_disassembler(void)
+{
+ ud_init(&ud);
+ ud_set_syntax(&ud, UD_SYN_ATT);
+}
+
+static const char *disassemble(unsigned char *insn, int len, uint64_t rip,
+ int cr0_pe, int eflags_vm,
+ int cs_d, int cs_l)
+{
+ int mode;
+
+ if (!cr0_pe)
+ mode = 16;
+ else if (eflags_vm)
+ mode = 16;
+ else if (cs_l)
+ mode = 64;
+ else if (cs_d)
+ mode = 32;
+ else
+ mode = 16;
+
+ ud_set_pc(&ud, rip);
+ ud_set_mode(&ud, mode);
+ ud_set_input_buffer(&ud, insn, len);
+ ud_disassemble(&ud);
+ return ud_insn_asm(&ud);
+}
+
+#else
+
+static void init_disassembler(void)
+{
+}
+
+static const char *disassemble(unsigned char *insn, int len, uint64_t rip,
+ int cr0_pe, int eflags_vm,
+ int cs_d, int cs_l)
+{
+ static char out[15*3+1];
+ int i;
+
+ for (i = 0; i < len; ++i)
+ sprintf(out + i * 3, "%02x ", insn[i]);
+ out[len*3-1] = '\0';
+ return out;
+}
+
+#endif
+
+
#define VMX_EXIT_REASONS \
_ER(EXCEPTION_NMI, 0) \
_ER(EXTERNAL_INTERRUPT, 1) \
@@ -99,6 +158,53 @@ static int kvm_exit_handler(struct trace_seq *s, struct record *record,
return 0;
}
+#define KVM_EMUL_INSN_F_CR0_PE (1 << 0)
+#define KVM_EMUL_INSN_F_EFL_VM (1 << 1)
+#define KVM_EMUL_INSN_F_CS_D (1 << 2)
+#define KVM_EMUL_INSN_F_CS_L (1 << 3)
+
+static int kvm_emulate_insn_handler(struct trace_seq *s, struct record *record,
+ struct event_format *event, void *context)
+{
+ unsigned long long rip, csbase, len, flags, failed;
+ int llen;
+ uint8_t *insn;
+ const char *disasm;
+
+ if (pevent_get_field_val(s, event, "rip", record, &rip, 1) < 0)
+ return -1;
+
+ if (pevent_get_field_val(s, event, "csbase", record, &csbase, 1) < 0)
+ return -1;
+
+ if (pevent_get_field_val(s, event, "len", record, &len, 1) < 0)
+ return -1;
+
+ if (pevent_get_field_val(s, event, "flags", record, &flags, 1) < 0)
+ return -1;
+
+ if (pevent_get_field_val(s, event, "failed", record, &failed, 1) < 0)
+ return -1;
+
+ insn = pevent_get_field_raw(s, event, "insn", record, &llen, 1);
+ if (!insn)
+ return -1;
+
+ disasm = disassemble(insn, len, rip,
+ flags & KVM_EMUL_INSN_F_CR0_PE,
+ flags & KVM_EMUL_INSN_F_EFL_VM,
+ flags & KVM_EMUL_INSN_F_CS_D,
+ flags & KVM_EMUL_INSN_F_CS_L);
+
+ trace_seq_printf(s, "%llx:%llx: %s%s", csbase, rip, disasm,
+ failed ? " FAIL" : "");
+
+ pevent_print_num_field(s, " rip %0xlx", event, "guest_rip", record, 1);
+
+ return 0;
+}
+
+
static int kvm_nested_vmexit_inject_handler(struct trace_seq *s, struct record *record,
struct event_format *event, void *context)
{
@@ -199,9 +305,14 @@ static int kvm_mmu_get_page_handler(struct trace_seq *s, struct record *record,
int PEVENT_PLUGIN_LOADER(struct pevent *pevent)
{
+ init_disassembler();
+
pevent_register_event_handler(pevent, -1, "kvm", "kvm_exit",
kvm_exit_handler, NULL);
+ pevent_register_event_handler(pevent, -1, "kvm", "kvm_emulate_insn",
+ kvm_emulate_insn_handler, NULL);
+
pevent_register_event_handler(pevent, -1, "kvm", "kvm_nested_vmexit",
kvm_nested_vmexit_handler, NULL);
--
1.7.2.3
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