[PATCH 16/17] plugins: add plugin API to read guest memory

From: Rowan Hart <rowanbhart(a)gmail.com&gt; Signed-off-by: Rowan Hart <rowanbhart(a)gmail.com&gt; Reviewed-by: Pierrick Bouvier <pierrick.bouvier(a)linaro.org&gt; Message-Id: <20240827215329.248434-2-rowanbhart(a)gmail.com&gt; [AJB: tweaked cpu_memory_rw_debug call] Signed-off-by: Alex Bennée <alex.bennee(a)linaro.org&gt; --- vAJB: - explicit bool for cpu_memory_rw_debug --- include/qemu/qemu-plugin.h | 32 +++++++++++++++++++++++++++++++- plugins/api.c | 20 ++++++++++++++++++++ plugins/qemu-plugins.symbols | 1 + 3 files changed, 52 insertions(+), 1 deletion(-) diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h index 649ce89815..2015d6b409 100644 --- a/include/qemu/qemu-plugin.h +++ b/include/qemu/qemu-plugin.h @@ -57,11 +57,19 @@ typedef uint64_t qemu_plugin_id_t; * - Remove qemu_plugin_register_vcpu_{tb, insn, mem}_exec_inline. * Those functions are replaced by *_per_vcpu variants, which guarantee * thread-safety for operations. + * + * version 3: + * - modified arguments and return value of qemu_plugin_insn_data to copy + * the data into a user-provided buffer instead of returning a pointer + * to the data. + * + * version 4: + * - added qemu_plugin_read_memory_vaddr */ extern QEMU_PLUGIN_EXPORT int qemu_plugin_version; -#define QEMU_PLUGIN_VERSION 3 +#define QEMU_PLUGIN_VERSION 4 /** * struct qemu_info_t - system information for plugins @@ -884,6 +892,28 @@ typedef struct { QEMU_PLUGIN_API GArray *qemu_plugin_get_registers(void); +/** + * qemu_plugin_read_memory_vaddr() - read from memory using a virtual address + * + * @addr: A virtual address to read from + * @data: A byte array to store data into + * @len: The number of bytes to read, starting from @addr + * + * @len bytes of data is read starting at @addr and stored into @data. If @data + * is not large enough to hold @len bytes, it will be expanded to the necessary + * size, reallocating if necessary. @len must be greater than 0. + * + * This function does not ensure writes are flushed prior to reading, so + * callers should take care when calling this function in plugin callbacks to + * avoid attempting to read data which may not yet be written and should use + * the memory callback API instead. + * + * Returns true on success and false on failure. + */ +QEMU_PLUGIN_API +bool qemu_plugin_read_memory_vaddr(uint64_t addr, + GByteArray *data, size_t len); + /** * qemu_plugin_read_register() - read register for current vCPU * diff --git a/plugins/api.c b/plugins/api.c index 3316d4a04d..24ea64e2de 100644 --- a/plugins/api.c +++ b/plugins/api.c @@ -560,6 +560,26 @@ GArray *qemu_plugin_get_registers(void) return create_register_handles(regs); } +bool qemu_plugin_read_memory_vaddr(vaddr addr, GByteArray *data, size_t len) +{ + g_assert(current_cpu); + + if (len == 0) { + return false; + } + + g_byte_array_set_size(data, len); + + int result = cpu_memory_rw_debug(current_cpu, addr, data->data, + data->len, false); + + if (result < 0) { + return false; + } + + return true; +} + int qemu_plugin_read_register(struct qemu_plugin_register *reg, GByteArray *buf) { g_assert(current_cpu); diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols index eed9d8abd9..032661f9ea 100644 --- a/plugins/qemu-plugins.symbols +++ b/plugins/qemu-plugins.symbols @@ -21,6 +21,7 @@ qemu_plugin_num_vcpus; qemu_plugin_outs; qemu_plugin_path_to_binary; + qemu_plugin_read_memory_vaddr; qemu_plugin_read_register; qemu_plugin_register_atexit_cb; qemu_plugin_register_flush_cb; -- 2.39.2