Merge remote-tracking branch 'remotes/stsquad/tags/pull-misc-6.0-updates-170321-2' into staging

Final fixes for 6.0

  - plugins physical address changes
  - syscall tracking plugin
  - plugin kernel-doc comments (without integration)
  - libfdt build fix for guest-loader

# gpg: Signature made Wed 17 Mar 2021 07:19:23 GMT
# gpg:                using RSA key 6685AE99E75167BCAFC8DF35FBD0DB095A9E2A44
# gpg: Good signature from "Alex Bennée (Master Work Key) <alex.bennee@linaro.org>" [full]
# Primary key fingerprint: 6685 AE99 E751 67BC AFC8  DF35 FBD0 DB09 5A9E 2A44

* remotes/stsquad/tags/pull-misc-6.0-updates-170321-2:
  hw/core: Only build guest-loader if libfdt is available
  plugins: Fixes typo in qemu-plugin.h
  plugins: getting qemu_plugin_get_hwaddr only expose one function prototype
  plugins: expand kernel-doc for memory query and instrumentation
  plugins: expand kernel-doc for instruction query and instrumentation
  plugins: expand inline exec kernel-doc documentation.
  plugins: add qemu_plugin_id_t to kernel-doc
  plugins: add qemu_plugin_cb_flags to kernel-doc
  plugins: expand the typedef kernel-docs for translation
  plugins: expand the callback typedef kernel-docs
  plugins: cleanup kernel-doc for qemu_plugin_install
  plugins: expand kernel-doc for qemu_info_t
  plugins: Expose physical addresses instead of device offsets
  plugins: new syscalls plugin
  utils: Use fixed-point arithmetic in qemu_strtosz

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

8 files changed, 261 insertions, 59 deletions

diff --git a/contrib/plugins/hotpages.c b/contrib/plugins/hotpages.c
index eacc678eac..bf53267532 100644
--- a/contrib/plugins/hotpages.c
+++ b/contrib/plugins/hotpages.c
@@ -122,7 +122,7 @@ static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
         }
     } else {
         if (hwaddr && !qemu_plugin_hwaddr_is_io(hwaddr)) {
-            page = (uint64_t) qemu_plugin_hwaddr_device_offset(hwaddr);
+            page = (uint64_t) qemu_plugin_hwaddr_phys_addr(hwaddr);
         } else {
             page = vaddr;
         }
diff --git a/contrib/plugins/hwprofile.c b/contrib/plugins/hwprofile.c
index 6dac1d5f85..faf216ac00 100644
--- a/contrib/plugins/hwprofile.c
+++ b/contrib/plugins/hwprofile.c
@@ -201,7 +201,7 @@ static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
         return;
     } else {
         const char *name = qemu_plugin_hwaddr_device_name(hwaddr);
-        uint64_t off = qemu_plugin_hwaddr_device_offset(hwaddr);
+        uint64_t off = qemu_plugin_hwaddr_phys_addr(hwaddr);
         bool is_write = qemu_plugin_mem_is_store(meminfo);
         DeviceCounts *counts;
 
diff --git a/hw/core/Kconfig b/hw/core/Kconfig
index fdf03514d7..9397503656 100644
--- a/hw/core/Kconfig
+++ b/hw/core/Kconfig
@@ -11,6 +11,11 @@ config GENERIC_LOADER
     bool
     default y
 
+config GUEST_LOADER
+    bool
+    default y
+    depends on TCG
+
 config OR_IRQ
     bool
 
diff --git a/hw/core/meson.build b/hw/core/meson.build
index 9cd72edf51..59f1605bb0 100644
--- a/hw/core/meson.build
+++ b/hw/core/meson.build
@@ -16,6 +16,7 @@ hwcore_files = files(
 common_ss.add(files('cpu.c'))
 common_ss.add(when: 'CONFIG_FITLOADER', if_true: files('loader-fit.c'))
 common_ss.add(when: 'CONFIG_GENERIC_LOADER', if_true: files('generic-loader.c'))
+common_ss.add(when: ['CONFIG_GUEST_LOADER', fdt], if_true: files('guest-loader.c'))
 common_ss.add(when: 'CONFIG_OR_IRQ', if_true: files('or-irq.c'))
 common_ss.add(when: 'CONFIG_PLATFORM_BUS', if_true: files('platform-bus.c'))
 common_ss.add(when: 'CONFIG_PTIMER', if_true: files('ptimer.c'))
@@ -37,8 +38,6 @@ softmmu_ss.add(files(
   'clock-vmstate.c',
 ))
 
-softmmu_ss.add(when: 'CONFIG_TCG', if_true: files('guest-loader.c'))
-
 specific_ss.add(when: 'CONFIG_SOFTMMU', if_true: files(
   'machine-qmp-cmds.c',
   'numa.c',
diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index c66507fe8f..97cdfd7761 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -32,6 +32,9 @@
   #define QEMU_PLUGIN_LOCAL  __attribute__((visibility("hidden")))
 #endif
 
+/**
+ * typedef qemu_plugin_id_t - Unique plugin ID
+ */
 typedef uint64_t qemu_plugin_id_t;
 
 /*
@@ -47,24 +50,32 @@ typedef uint64_t qemu_plugin_id_t;
 
 extern QEMU_PLUGIN_EXPORT int qemu_plugin_version;
 
-#define QEMU_PLUGIN_VERSION 0
+#define QEMU_PLUGIN_VERSION 1
 
-typedef struct {
-    /* string describing architecture */
+/**
+ * struct qemu_info_t - system information for plugins
+ *
+ * This structure provides for some limited information about the
+ * system to allow the plugin to make decisions on how to proceed. For
+ * example it might only be suitable for running on some guest
+ * architectures or when under full system emulation.
+ */
+typedef struct qemu_info_t {
+    /** @target_name: string describing architecture */
     const char *target_name;
+    /** @version: minimum and current plugin API level */
     struct {
         int min;
         int cur;
     } version;
-    /* is this a full system emulation? */
+    /** @system_emulation: is this a full system emulation? */
     bool system_emulation;
     union {
-        /*
-         * smp_vcpus may change if vCPUs can be hot-plugged, max_vcpus
-         * is the system-wide limit.
-         */
+        /** @system: information relevant to system emulation */
         struct {
+            /** @system.smp_vcpus: initial number of vCPUs */
             int smp_vcpus;
+            /** @system.max_vcpus: maximum possible number of vCPUs */
             int max_vcpus;
         } system;
     };
@@ -77,31 +88,50 @@ typedef struct {
  * @argc: number of arguments
  * @argv: array of arguments (@argc elements)
  *
- * All plugins must export this symbol.
- *
- * Note: Calling qemu_plugin_uninstall() from this function is a bug. To raise
- * an error during install, return !0.
+ * All plugins must export this symbol which is called when the plugin
+ * is first loaded. Calling qemu_plugin_uninstall() from this function
+ * is a bug.
  *
  * Note: @info is only live during the call. Copy any information we
- * want to keep.
+ * want to keep. @argv remains valid throughout the lifetime of the
+ * loaded plugin.
  *
- * Note: @argv remains valid throughout the lifetime of the loaded plugin.
+ * Return: 0 on successful loading, !0 for an error.
  */
 QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
                                            const qemu_info_t *info,
                                            int argc, char **argv);
 
-/*
- * Prototypes for the various callback styles we will be registering
- * in the following functions.
+/**
+ * typedef qemu_plugin_simple_cb_t - simple callback
+ * @id: the unique qemu_plugin_id_t
+ *
+ * This callback passes no information aside from the unique @id.
  */
 typedef void (*qemu_plugin_simple_cb_t)(qemu_plugin_id_t id);
 
+/**
+ * typedef qemu_plugin_udata_cb_t - callback with user data
+ * @id: the unique qemu_plugin_id_t
+ * @userdata: a pointer to some user data supplied when the callback
+ * was registered.
+ */
 typedef void (*qemu_plugin_udata_cb_t)(qemu_plugin_id_t id, void *userdata);
 
+/**
+ * typedef qemu_plugin_vcpu_simple_cb_t - vcpu callback
+ * @id: the unique qemu_plugin_id_t
+ * @vcpu_index: the current vcpu context
+ */
 typedef void (*qemu_plugin_vcpu_simple_cb_t)(qemu_plugin_id_t id,
                                              unsigned int vcpu_index);
 
+/**
+ * typedef qemu_plugin_vcpu_udata_cb_t - vcpu callback
+ * @vcpu_index: the current vcpu context
+ * @userdata: a pointer to some user data supplied when the callback
+ * was registered.
+ */
 typedef void (*qemu_plugin_vcpu_udata_cb_t)(unsigned int vcpu_index,
                                             void *userdata);
 
@@ -175,17 +205,25 @@ void qemu_plugin_register_vcpu_idle_cb(qemu_plugin_id_t id,
 void qemu_plugin_register_vcpu_resume_cb(qemu_plugin_id_t id,
                                          qemu_plugin_vcpu_simple_cb_t cb);
 
-/*
- * Opaque types that the plugin is given during the translation and
- * instrumentation phase.
- */
+/** struct qemu_plugin_tb - Opaque handle for a translation block */
 struct qemu_plugin_tb;
+/** struct qemu_plugin_insn - Opaque handle for a translated instruction */
 struct qemu_plugin_insn;
 
+/**
+ * enum qemu_plugin_cb_flags - type of callback
+ *
+ * @QEMU_PLUGIN_CB_NO_REGS: callback does not access the CPU's regs
+ * @QEMU_PLUGIN_CB_R_REGS: callback reads the CPU's regs
+ * @QEMU_PLUGIN_CB_RW_REGS: callback reads and writes the CPU's regs
+ *
+ * Note: currently unused, plugins cannot read or change system
+ * register state.
+ */
 enum qemu_plugin_cb_flags {
-    QEMU_PLUGIN_CB_NO_REGS, /* callback does not access the CPU's regs */
-    QEMU_PLUGIN_CB_R_REGS,  /* callback reads the CPU's regs */
-    QEMU_PLUGIN_CB_RW_REGS, /* callback reads and writes the CPU's regs */
+    QEMU_PLUGIN_CB_NO_REGS,
+    QEMU_PLUGIN_CB_R_REGS,
+    QEMU_PLUGIN_CB_RW_REGS,
 };
 
 enum qemu_plugin_mem_rw {
@@ -195,6 +233,14 @@ enum qemu_plugin_mem_rw {
 };
 
 /**
+ * typedef qemu_plugin_vcpu_tb_trans_cb_t - translation callback
+ * @id: unique plugin id
+ * @tb: opaque handle used for querying and instrumenting a block.
+ */
+typedef void (*qemu_plugin_vcpu_tb_trans_cb_t)(qemu_plugin_id_t id,
+                                               struct qemu_plugin_tb *tb);
+
+/**
  * qemu_plugin_register_vcpu_tb_trans_cb() - register a translate cb
  * @id: plugin ID
  * @cb: callback function
@@ -206,14 +252,11 @@ enum qemu_plugin_mem_rw {
  * callbacks to be triggered when the block or individual instruction
  * executes.
  */
-typedef void (*qemu_plugin_vcpu_tb_trans_cb_t)(qemu_plugin_id_t id,
-                                               struct qemu_plugin_tb *tb);
-
 void qemu_plugin_register_vcpu_tb_trans_cb(qemu_plugin_id_t id,
                                            qemu_plugin_vcpu_tb_trans_cb_t cb);
 
 /**
- * qemu_plugin_register_vcpu_tb_trans_exec_cb() - register execution callback
+ * qemu_plugin_register_vcpu_tb_exec_cb() - register execution callback
  * @tb: the opaque qemu_plugin_tb handle for the translation
  * @cb: callback function
  * @flags: does the plugin read or write the CPU's registers?
@@ -226,12 +269,20 @@ void qemu_plugin_register_vcpu_tb_exec_cb(struct qemu_plugin_tb *tb,
                                           enum qemu_plugin_cb_flags flags,
                                           void *userdata);
 
+/**
+ * enum qemu_plugin_op - describes an inline op
+ *
+ * @QEMU_PLUGIN_INLINE_ADD_U64: add an immediate value uint64_t
+ *
+ * Note: currently only a single inline op is supported.
+ */
+
 enum qemu_plugin_op {
     QEMU_PLUGIN_INLINE_ADD_U64,
 };
 
 /**
- * qemu_plugin_register_vcpu_tb_trans_exec_inline() - execution inline op
+ * qemu_plugin_register_vcpu_tb_exec_inline() - execution inline op
  * @tb: the opaque qemu_plugin_tb handle for the translation
  * @op: the type of qemu_plugin_op (e.g. ADD_U64)
  * @ptr: the target memory location for the op
@@ -240,6 +291,9 @@ enum qemu_plugin_op {
  * Insert an inline op to every time a translated unit executes.
  * Useful if you just want to increment a single counter somewhere in
  * memory.
+ *
+ * Note: ops are not atomic so in multi-threaded/multi-smp situations
+ * you will get inexact results.
  */
 void qemu_plugin_register_vcpu_tb_exec_inline(struct qemu_plugin_tb *tb,
                                               enum qemu_plugin_op op,
@@ -262,7 +316,6 @@ void qemu_plugin_register_vcpu_insn_exec_cb(struct qemu_plugin_insn *insn,
 /**
  * qemu_plugin_register_vcpu_insn_exec_inline() - insn execution inline op
  * @insn: the opaque qemu_plugin_insn handle for an instruction
- * @cb: callback function
  * @op: the type of qemu_plugin_op (e.g. ADD_U64)
  * @ptr: the target memory location for the op
  * @imm: the op data (e.g. 1)
@@ -274,41 +327,114 @@ void qemu_plugin_register_vcpu_insn_exec_inline(struct qemu_plugin_insn *insn,
                                                 enum qemu_plugin_op op,
                                                 void *ptr, uint64_t imm);
 
-/*
- * Helpers to query information about the instructions in a block
+/**
+ * qemu_plugin_tb_n_insns() - query helper for number of insns in TB
+ * @tb: opaque handle to TB passed to callback
+ *
+ * Returns: number of instructions in this block
  */
 size_t qemu_plugin_tb_n_insns(const struct qemu_plugin_tb *tb);
 
+/**
+ * qemu_plugin_tb_vaddr() - query helper for vaddr of TB start
+ * @tb: opaque handle to TB passed to callback
+ *
+ * Returns: virtual address of block start
+ */
 uint64_t qemu_plugin_tb_vaddr(const struct qemu_plugin_tb *tb);
 
+/**
+ * qemu_plugin_tb_get_insn() - retrieve handle for instruction
+ * @tb: opaque handle to TB passed to callback
+ * @idx: instruction number, 0 indexed
+ *
+ * The returned handle can be used in follow up helper queries as well
+ * as when instrumenting an instruction. It is only valid for the
+ * lifetime of the callback.
+ *
+ * Returns: opaque handle to instruction
+ */
 struct qemu_plugin_insn *
 qemu_plugin_tb_get_insn(const struct qemu_plugin_tb *tb, size_t idx);
 
+/**
+ * qemu_plugin_insn_data() - return ptr to instruction data
+ * @insn: opaque instruction handle from qemu_plugin_tb_get_insn()
+ *
+ * Note: data is only valid for duration of callback. See
+ * qemu_plugin_insn_size() to calculate size of stream.
+ *
+ * Returns: pointer to a stream of bytes containing the value of this
+ * instructions opcode.
+ */
 const void *qemu_plugin_insn_data(const struct qemu_plugin_insn *insn);
 
+/**
+ * qemu_plugin_insn_size() - return size of instruction
+ * @insn: opaque instruction handle from qemu_plugin_tb_get_insn()
+ *
+ * Returns: size of instruction in bytes
+ */
 size_t qemu_plugin_insn_size(const struct qemu_plugin_insn *insn);
 
+/**
+ * qemu_plugin_insn_vaddr() - return vaddr of instruction
+ * @insn: opaque instruction handle from qemu_plugin_tb_get_insn()
+ *
+ * Returns: virtual address of instruction
+ */
 uint64_t qemu_plugin_insn_vaddr(const struct qemu_plugin_insn *insn);
+
+/**
+ * qemu_plugin_insn_haddr() - return hardware addr of instruction
+ * @insn: opaque instruction handle from qemu_plugin_tb_get_insn()
+ *
+ * Returns: hardware (physical) target address of instruction
+ */
 void *qemu_plugin_insn_haddr(const struct qemu_plugin_insn *insn);
 
-/*
- * Memory Instrumentation
+/**
+ * typedef qemu_plugin_meminfo_t - opaque memory transaction handle
  *
- * The anonymous qemu_plugin_meminfo_t and qemu_plugin_hwaddr types
- * can be used in queries to QEMU to get more information about a
- * given memory access.
+ * This can be further queried using the qemu_plugin_mem_* query
+ * functions.
  */
 typedef uint32_t qemu_plugin_meminfo_t;
+/** struct qemu_plugin_hwaddr - opaque hw address handle */
 struct qemu_plugin_hwaddr;
 
-/* meminfo queries */
+/**
+ * qemu_plugin_mem_size_shift() - get size of access
+ * @info: opaque memory transaction handle
+ *
+ * Returns: size of access in ^2 (0=byte, 1=16bit, 2=32bit etc...)
+ */
 unsigned int qemu_plugin_mem_size_shift(qemu_plugin_meminfo_t info);
+/**
+ * qemu_plugin_mem_is_sign_extended() - was the access sign extended
+ * @info: opaque memory transaction handle
+ *
+ * Returns: true if it was, otherwise false
+ */
 bool qemu_plugin_mem_is_sign_extended(qemu_plugin_meminfo_t info);
+/**
+ * qemu_plugin_mem_is_big_endian() - was the access big endian
+ * @info: opaque memory transaction handle
+ *
+ * Returns: true if it was, otherwise false
+ */
 bool qemu_plugin_mem_is_big_endian(qemu_plugin_meminfo_t info);
+/**
+ * qemu_plugin_mem_is_store() - was the access a store
+ * @info: opaque memory transaction handle
+ *
+ * Returns: true if it was, otherwise false
+ */
 bool qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info);
 
-/*
- * qemu_plugin_get_hwaddr():
+/**
+ * qemu_plugin_get_hwaddr() - return handle for memory operation
+ * @info: opaque memory info structure
  * @vaddr: the virtual address of the memory operation
  *
  * For system emulation returns a qemu_plugin_hwaddr handle to query
@@ -323,12 +449,30 @@ struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
                                                   uint64_t vaddr);
 
 /*
- * The following additional queries can be run on the hwaddr structure
- * to return information about it. For non-IO accesses the device
- * offset will be into the appropriate block of RAM.
+ * The following additional queries can be run on the hwaddr structure to
+ * return information about it - namely whether it is for an IO access and the
+ * physical address associated with the access.
+ */
+
+/**
+ * qemu_plugin_hwaddr_is_io() - query whether memory operation is IO
+ * @haddr: address handle from qemu_plugin_get_hwaddr()
+ *
+ * Returns true if the handle's memory operation is to memory-mapped IO, or
+ * false if it is to RAM
  */
 bool qemu_plugin_hwaddr_is_io(const struct qemu_plugin_hwaddr *haddr);
-uint64_t qemu_plugin_hwaddr_device_offset(const struct qemu_plugin_hwaddr *haddr);
+
+/**
+ * qemu_plugin_hwaddr_phys_addr() - query physical address for memory operation
+ * @haddr: address handle from qemu_plugin_get_hwaddr()
+ *
+ * Returns the physical address associated with the memory operation
+ *
+ * Note that the returned physical address may not be unique if you are dealing
+ * with multiple address spaces.
+ */
+uint64_t qemu_plugin_hwaddr_phys_addr(const struct qemu_plugin_hwaddr *haddr);
 
 /*
  * Returns a string representing the device. The string is valid for
diff --git a/plugins/api.c b/plugins/api.c
index 0b04380d57..b22998cd7c 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -40,6 +40,7 @@
 #include "sysemu/sysemu.h"
 #include "tcg/tcg.h"
 #include "exec/exec-all.h"
+#include "exec/ram_addr.h"
 #include "disas/disas.h"
 #include "plugin.h"
 #ifndef CONFIG_USER_ONLY
@@ -265,10 +266,12 @@ bool qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info)
 
 #ifdef CONFIG_SOFTMMU
 static __thread struct qemu_plugin_hwaddr hwaddr_info;
+#endif
 
 struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
                                                   uint64_t vaddr)
 {
+#ifdef CONFIG_SOFTMMU
     CPUState *cpu = current_cpu;
     unsigned int mmu_idx = info >> TRACE_MEM_MMU_SHIFT;
     hwaddr_info.is_store = info & TRACE_MEM_ST;
@@ -280,14 +283,10 @@ struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
     }
 
     return &hwaddr_info;
-}
 #else
-struct qemu_plugin_hwaddr *qemu_plugin_get_hwaddr(qemu_plugin_meminfo_t info,
-                                                  uint64_t vaddr)
-{
     return NULL;
-}
 #endif
+}
 
 bool qemu_plugin_hwaddr_is_io(const struct qemu_plugin_hwaddr *haddr)
 {
@@ -298,19 +297,25 @@ bool qemu_plugin_hwaddr_is_io(const struct qemu_plugin_hwaddr *haddr)
 #endif
 }
 
-uint64_t qemu_plugin_hwaddr_device_offset(const struct qemu_plugin_hwaddr *haddr)
+uint64_t qemu_plugin_hwaddr_phys_addr(const struct qemu_plugin_hwaddr *haddr)
 {
 #ifdef CONFIG_SOFTMMU
     if (haddr) {
         if (!haddr->is_io) {
-            ram_addr_t ram_addr = qemu_ram_addr_from_host((void *) haddr->v.ram.hostaddr);
-            if (ram_addr == RAM_ADDR_INVALID) {
+            RAMBlock *block;
+            ram_addr_t offset;
+            void *hostaddr = (void *) haddr->v.ram.hostaddr;
+
+            block = qemu_ram_block_from_host(hostaddr, false, &offset);
+            if (!block) {
                 error_report("Bad ram pointer %"PRIx64"", haddr->v.ram.hostaddr);
                 abort();
             }
-            return ram_addr;
+
+            return block->offset + offset + block->mr->addr;
         } else {
-            return haddr->v.io.offset;
+            MemoryRegionSection *mrs = haddr->v.io.section;
+            return haddr->v.io.offset + mrs->mr->addr;
         }
     }
 #endif
diff --git a/tests/plugin/meson.build b/tests/plugin/meson.build
index 1eacfa6e35..2bbfc4b19e 100644
--- a/tests/plugin/meson.build
+++ b/tests/plugin/meson.build
@@ -1,5 +1,5 @@
 t = []
-foreach i : ['bb', 'empty', 'insn', 'mem']
+foreach i : ['bb', 'empty', 'insn', 'mem', 'syscall']
   t += shared_module(i, files(i + '.c'),
                      include_directories: '../../include/qemu',
                      dependencies: glib)
diff --git a/tests/plugin/syscall.c b/tests/plugin/syscall.c
new file mode 100644
index 0000000000..53ee2ab6c4
--- /dev/null
+++ b/tests/plugin/syscall.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2020, Matthias Weckbecker <matthias@weckbecker.name>
+ *
+ * License: GNU GPL, version 2 or later.
+ *   See the COPYING file in the top-level directory.
+ */
+#include <inttypes.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <glib.h>
+
+#include <qemu-plugin.h>
+
+QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
+
+static void vcpu_syscall(qemu_plugin_id_t id, unsigned int vcpu_index,
+                         int64_t num, uint64_t a1, uint64_t a2,
+                         uint64_t a3, uint64_t a4, uint64_t a5,
+                         uint64_t a6, uint64_t a7, uint64_t a8)
+{
+    g_autofree gchar *out = g_strdup_printf("syscall #%" PRIi64 "\n", num);
+    qemu_plugin_outs(out);
+}
+
+static void vcpu_syscall_ret(qemu_plugin_id_t id, unsigned int vcpu_idx,
+                             int64_t num, int64_t ret)
+{
+    g_autofree gchar *out;
+    out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64 "\n",
+            num, ret);
+    qemu_plugin_outs(out);
+}
+
+/* ************************************************************************* */
+
+static void plugin_exit(qemu_plugin_id_t id, void *p) {}
+
+QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
+                                           const qemu_info_t *info,
+                                           int argc, char **argv)
+{
+    qemu_plugin_register_vcpu_syscall_cb(id, vcpu_syscall);
+    qemu_plugin_register_vcpu_syscall_ret_cb(id, vcpu_syscall_ret);
+    qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
+    return 0;
+}