[v5] plugins: access values during a memory read/write

[PATCH v5 3/7] plugins: extend API to get latest memory value accessed

Posted by Pierrick Bouvier 4 months, 3 weeks ago

This value can be accessed only during a memory callback, using
new qemu_plugin_mem_get_value function.

Returned value can be extended when QEMU will support accesses wider
than 128 bits.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1719
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2152
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
---
 include/qemu/qemu-plugin.h   | 32 ++++++++++++++++++++++++++++++++
 plugins/api.c                | 33 +++++++++++++++++++++++++++++++++
 plugins/qemu-plugins.symbols |  1 +
 3 files changed, 66 insertions(+)

diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
index c71c705b699..649ce89815f 100644
--- a/include/qemu/qemu-plugin.h
+++ b/include/qemu/qemu-plugin.h
@@ -262,6 +262,29 @@ enum qemu_plugin_mem_rw {
     QEMU_PLUGIN_MEM_RW,
 };
 
+enum qemu_plugin_mem_value_type {
+    QEMU_PLUGIN_MEM_VALUE_U8,
+    QEMU_PLUGIN_MEM_VALUE_U16,
+    QEMU_PLUGIN_MEM_VALUE_U32,
+    QEMU_PLUGIN_MEM_VALUE_U64,
+    QEMU_PLUGIN_MEM_VALUE_U128,
+};
+
+/* typedef qemu_plugin_mem_value - value accessed during a load/store */
+typedef struct {
+    enum qemu_plugin_mem_value_type type;
+    union {
+        uint8_t u8;
+        uint16_t u16;
+        uint32_t u32;
+        uint64_t u64;
+        struct {
+            uint64_t low;
+            uint64_t high;
+        } u128;
+    } data;
+} qemu_plugin_mem_value;
+
 /**
  * enum qemu_plugin_cond - condition to enable callback
  *
@@ -551,6 +574,15 @@ bool qemu_plugin_mem_is_big_endian(qemu_plugin_meminfo_t info);
 QEMU_PLUGIN_API
 bool qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info);
 
+/**
+ * qemu_plugin_mem_get_mem_value() - return last value loaded/stored
+ * @info: opaque memory transaction handle
+ *
+ * Returns: memory value
+ */
+QEMU_PLUGIN_API
+qemu_plugin_mem_value qemu_plugin_mem_get_value(qemu_plugin_meminfo_t info);
+
 /**
  * qemu_plugin_get_hwaddr() - return handle for memory operation
  * @info: opaque memory info structure
diff --git a/plugins/api.c b/plugins/api.c
index 2ff13d09de6..3316d4a04d4 100644
--- a/plugins/api.c
+++ b/plugins/api.c
@@ -351,6 +351,39 @@ bool qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info)
     return get_plugin_meminfo_rw(info) & QEMU_PLUGIN_MEM_W;
 }
 
+qemu_plugin_mem_value qemu_plugin_mem_get_value(qemu_plugin_meminfo_t info)
+{
+    uint64_t low = current_cpu->neg.plugin_mem_value_low;
+    qemu_plugin_mem_value value;
+
+    switch (qemu_plugin_mem_size_shift(info)) {
+    case 0:
+        value.type = QEMU_PLUGIN_MEM_VALUE_U8;
+        value.data.u8 = (uint8_t)low;
+        break;
+    case 1:
+        value.type = QEMU_PLUGIN_MEM_VALUE_U16;
+        value.data.u16 = (uint16_t)low;
+        break;
+    case 2:
+        value.type = QEMU_PLUGIN_MEM_VALUE_U32;
+        value.data.u32 = (uint32_t)low;
+        break;
+    case 3:
+        value.type = QEMU_PLUGIN_MEM_VALUE_U64;
+        value.data.u64 = low;
+        break;
+    case 4:
+        value.type = QEMU_PLUGIN_MEM_VALUE_U128;
+        value.data.u128.low = low;
+        value.data.u128.high = current_cpu->neg.plugin_mem_value_high;
+        break;
+    default:
+        g_assert_not_reached();
+    }
+    return value;
+}
+
 /*
  * Virtual Memory queries
  */
diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
index ca773d8d9fe..eed9d8abd90 100644
--- a/plugins/qemu-plugins.symbols
+++ b/plugins/qemu-plugins.symbols
@@ -13,6 +13,7 @@
   qemu_plugin_insn_size;
   qemu_plugin_insn_symbol;
   qemu_plugin_insn_vaddr;
+  qemu_plugin_mem_get_value;
   qemu_plugin_mem_is_big_endian;
   qemu_plugin_mem_is_sign_extended;
   qemu_plugin_mem_is_store;
-- 
2.39.2

RE: [PATCH v5 3/7] plugins: extend API to get latest memory value accessed

Posted by Xingtao Yao (Fujitsu) via 4 months, 3 weeks ago

Reviewed-by: Xingtao Yao <yaoxt.fnst@fujitsu.com>

> -----Original Message-----
> From: qemu-devel-bounces+yaoxt.fnst=fujitsu.com@nongnu.org
> <qemu-devel-bounces+yaoxt.fnst=fujitsu.com@nongnu.org> On Behalf Of
> Pierrick Bouvier
> Sent: Friday, July 5, 2024 8:34 AM
> To: qemu-devel@nongnu.org
> Cc: Alexandre Iooss <erdnaxe@crans.org>; Richard Henderson
> <richard.henderson@linaro.org>; Marcel Apfelbaum
> <marcel.apfelbaum@gmail.com>; Pierrick Bouvier <pierrick.bouvier@linaro.org>;
> Alex Bennée <alex.bennee@linaro.org>; Paolo Bonzini <pbonzini@redhat.com>;
> Yanan Wang <wangyanan55@huawei.com>; Mahmoud Mandour
> <ma.mandourr@gmail.com>; Eduardo Habkost <eduardo@habkost.net>; Philippe
> Mathieu-Daudé <philmd@linaro.org>
> Subject: [PATCH v5 3/7] plugins: extend API to get latest memory value accessed
> 
> This value can be accessed only during a memory callback, using
> new qemu_plugin_mem_get_value function.
> 
> Returned value can be extended when QEMU will support accesses wider
> than 128 bits.
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1719
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2152
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> ---
>  include/qemu/qemu-plugin.h   | 32
> ++++++++++++++++++++++++++++++++
>  plugins/api.c                | 33
> +++++++++++++++++++++++++++++++++
>  plugins/qemu-plugins.symbols |  1 +
>  3 files changed, 66 insertions(+)
> 
> diff --git a/include/qemu/qemu-plugin.h b/include/qemu/qemu-plugin.h
> index c71c705b699..649ce89815f 100644
> --- a/include/qemu/qemu-plugin.h
> +++ b/include/qemu/qemu-plugin.h
> @@ -262,6 +262,29 @@ enum qemu_plugin_mem_rw {
>      QEMU_PLUGIN_MEM_RW,
>  };
> 
> +enum qemu_plugin_mem_value_type {
> +    QEMU_PLUGIN_MEM_VALUE_U8,
> +    QEMU_PLUGIN_MEM_VALUE_U16,
> +    QEMU_PLUGIN_MEM_VALUE_U32,
> +    QEMU_PLUGIN_MEM_VALUE_U64,
> +    QEMU_PLUGIN_MEM_VALUE_U128,
> +};
> +
> +/* typedef qemu_plugin_mem_value - value accessed during a load/store */
> +typedef struct {
> +    enum qemu_plugin_mem_value_type type;
> +    union {
> +        uint8_t u8;
> +        uint16_t u16;
> +        uint32_t u32;
> +        uint64_t u64;
> +        struct {
> +            uint64_t low;
> +            uint64_t high;
> +        } u128;
> +    } data;
> +} qemu_plugin_mem_value;
> +
>  /**
>   * enum qemu_plugin_cond - condition to enable callback
>   *
> @@ -551,6 +574,15 @@ bool
> qemu_plugin_mem_is_big_endian(qemu_plugin_meminfo_t info);
>  QEMU_PLUGIN_API
>  bool qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info);
> 
> +/**
> + * qemu_plugin_mem_get_mem_value() - return last value loaded/stored
> + * @info: opaque memory transaction handle
> + *
> + * Returns: memory value
> + */
> +QEMU_PLUGIN_API
> +qemu_plugin_mem_value
> qemu_plugin_mem_get_value(qemu_plugin_meminfo_t info);
> +
>  /**
>   * qemu_plugin_get_hwaddr() - return handle for memory operation
>   * @info: opaque memory info structure
> diff --git a/plugins/api.c b/plugins/api.c
> index 2ff13d09de6..3316d4a04d4 100644
> --- a/plugins/api.c
> +++ b/plugins/api.c
> @@ -351,6 +351,39 @@ bool
> qemu_plugin_mem_is_store(qemu_plugin_meminfo_t info)
>      return get_plugin_meminfo_rw(info) & QEMU_PLUGIN_MEM_W;
>  }
> 
> +qemu_plugin_mem_value
> qemu_plugin_mem_get_value(qemu_plugin_meminfo_t info)
> +{
> +    uint64_t low = current_cpu->neg.plugin_mem_value_low;
> +    qemu_plugin_mem_value value;
> +
> +    switch (qemu_plugin_mem_size_shift(info)) {
> +    case 0:
> +        value.type = QEMU_PLUGIN_MEM_VALUE_U8;
> +        value.data.u8 = (uint8_t)low;
> +        break;
> +    case 1:
> +        value.type = QEMU_PLUGIN_MEM_VALUE_U16;
> +        value.data.u16 = (uint16_t)low;
> +        break;
> +    case 2:
> +        value.type = QEMU_PLUGIN_MEM_VALUE_U32;
> +        value.data.u32 = (uint32_t)low;
> +        break;
> +    case 3:
> +        value.type = QEMU_PLUGIN_MEM_VALUE_U64;
> +        value.data.u64 = low;
> +        break;
> +    case 4:
> +        value.type = QEMU_PLUGIN_MEM_VALUE_U128;
> +        value.data.u128.low = low;
> +        value.data.u128.high = current_cpu->neg.plugin_mem_value_high;
> +        break;
> +    default:
> +        g_assert_not_reached();
> +    }
> +    return value;
> +}
> +
>  /*
>   * Virtual Memory queries
>   */
> diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
> index ca773d8d9fe..eed9d8abd90 100644
> --- a/plugins/qemu-plugins.symbols
> +++ b/plugins/qemu-plugins.symbols
> @@ -13,6 +13,7 @@
>    qemu_plugin_insn_size;
>    qemu_plugin_insn_symbol;
>    qemu_plugin_insn_vaddr;
> +  qemu_plugin_mem_get_value;
>    qemu_plugin_mem_is_big_endian;
>    qemu_plugin_mem_is_sign_extended;
>    qemu_plugin_mem_is_store;
> --
> 2.39.2
>

[PATCH v5 1/7] plugins: fix mem callback array size
[PATCH v5 2/7] plugins: save value during memory accesses
[PATCH v5 3/7] plugins: extend API to get latest memory value accessed
[PATCH v5 4/7] tests/tcg: add mechanism to run specific tests with plugins
[PATCH v5 5/7] tests/tcg: allow to check output of plugins
[PATCH v5 6/7] tests/plugin/mem: add option to print memory accesses
[PATCH v5 7/7] tests/tcg/x86_64: add test for plugin memory access