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([2604:3d08:9384:1d00::27bd]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-205155415a7sm30220295ad.183.2024.08.30.12.33.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 30 Aug 2024 12:33:39 -0700 (PDT) Message-ID: <31d95985-206a-4e67-8d61-3671b21f9fad@linaro.org> Date: Fri, 30 Aug 2024 12:33:38 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/1] plugins: add API to read guest CPU memory from hwaddr Content-Language: en-US From: Pierrick Bouvier To: Rowan Hart , qemu-devel@nongnu.org Cc: Alexandre Iooss , =?UTF-8?Q?Alex_Benn=C3=A9e?= , Mahmoud Mandour References: <20240828063224.291503-1-rowanbhart@gmail.com> <20240828063224.291503-2-rowanbhart@gmail.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::636; envelope-from=pierrick.bouvier@linaro.org; helo=mail-pl1-x636.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=ham 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org And by the way, feel free to integrate this with your other series (as it's a very similar topic) in a v3, so we can review both at the same time. Thanks, Pierrick On 8/30/24 12:30, Pierrick Bouvier wrote: > Hi Rowan, > > thanks for this good complement on the virt address read function. > > However, to be able to merge a new plugins API function, we must have a > concrete usage of it, through one of the existing plugin. > What could be a good demonstration of value brought by being able to > read a physical address? > > Thanks, > Pierrick > > On 8/27/24 23:32, Rowan Hart wrote: >> Signed-off-by: Rowan Hart >> --- >> include/qemu/qemu-plugin.h | 22 ++++++++++++++++++++++ >> plugins/api.c | 17 +++++++++++++++++ >> plugins/qemu-plugins.symbols | 2 ++ >> 3 files changed, 41 insertions(+) >> >> diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h >> index c71c705b69..25f39c0960 100644 >> --- a/include/qemu/qemu-plugin.h >> +++ b/include/qemu/qemu-plugin.h >> @@ -868,6 +868,28 @@ QEMU_PLUGIN_API >> int qemu_plugin_read_register(struct qemu_plugin_register *handle, >> GByteArray *buf); >> >> +/** >> + * qemu_plugin_read_cpu_memory_hwaddr() - read CPU memory from hwaddr >> + * >> + * @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_cpu_memory_hwaddr(uint64_t addr, >> + GByteArray *data, size_t len); >> + >> /** >> * qemu_plugin_scoreboard_new() - alloc a new scoreboard >> * >> diff --git a/plugins/api.c b/plugins/api.c >> index 2ff13d09de..c87bed6641 100644 >> --- a/plugins/api.c >> +++ b/plugins/api.c >> @@ -527,6 +527,22 @@ GArray *qemu_plugin_get_registers(void) >> return create_register_handles(regs); >> } >> >> +bool qemu_plugin_read_cpu_memory_hwaddr(uint64_t addr, >> + GByteArray *data, uint64_t len) >> +{ >> +#ifndef CONFIG_USER_ONLY >> + if (len == 0) { >> + return false; >> + } >> + >> + g_byte_array_set_size(data, len); >> + cpu_physical_memory_rw(addr, (void *)data->data, len, 0); >> + return true; >> +#else >> + return false; >> +#endif >> +} >> + >> int qemu_plugin_read_register(struct qemu_plugin_register *reg, GByteArray *buf) >> { >> g_assert(current_cpu); >> @@ -534,6 +550,7 @@ int qemu_plugin_read_register(struct qemu_plugin_register *reg, GByteArray *buf) >> return gdb_read_register(current_cpu, buf, GPOINTER_TO_INT(reg) - 1); >> } >> >> + >> struct qemu_plugin_scoreboard *qemu_plugin_scoreboard_new(size_t element_size) >> { >> return plugin_scoreboard_new(element_size); >> diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols >> index ca773d8d9f..5d9cfd71bb 100644 >> --- a/plugins/qemu-plugins.symbols >> +++ b/plugins/qemu-plugins.symbols >> @@ -20,6 +20,8 @@ >> qemu_plugin_num_vcpus; >> qemu_plugin_outs; >> qemu_plugin_path_to_binary; >> + qemu_plugin_read_cpu_memory_hwaddr; >> + qemu_plugin_read_io_memory_hwaddr; > > As you mentioned, you can remove the second one for v2. > >> qemu_plugin_read_register; >> qemu_plugin_register_atexit_cb; >> qemu_plugin_register_flush_cb;