[v3] plugins: access values during a memory read/write

[PATCH v3 1/7] plugins: fix mem callback array size

Posted by Pierrick Bouvier 2 months, 2 weeks ago

data was correctly copied, but size of array was not set
(g_array_sized_new only reserves memory, but does not set size).

As a result, callbacks were not called for code path relying on
plugin_register_vcpu_mem_cb().

Found when trying to trigger mem access callbacks for atomic
instructions.

Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
---
 accel/tcg/plugin-gen.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/accel/tcg/plugin-gen.c b/accel/tcg/plugin-gen.c
index b6bae32b997..ec89a085b43 100644
--- a/accel/tcg/plugin-gen.c
+++ b/accel/tcg/plugin-gen.c
@@ -85,8 +85,7 @@ static void gen_enable_mem_helper(struct qemu_plugin_tb *ptb,
     len = insn->mem_cbs->len;
     arr = g_array_sized_new(false, false,
                             sizeof(struct qemu_plugin_dyn_cb), len);
-    memcpy(arr->data, insn->mem_cbs->data,
-           len * sizeof(struct qemu_plugin_dyn_cb));
+    g_array_append_vals(arr, insn->mem_cbs->data, len);
     qemu_plugin_add_dyn_cb_arr(arr);
 
     tcg_gen_st_ptr(tcg_constant_ptr((intptr_t)arr), tcg_env,
-- 
2.39.2

RE: [PATCH v3 1/7] plugins: fix mem callback array size

Posted by Xingtao Yao (Fujitsu) via 2 months, 2 weeks ago


> -----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: Tuesday, July 2, 2024 9:10 AM
> To: qemu-devel@nongnu.org
> Cc: Eduardo Habkost <eduardo@habkost.net>; Alex Bennée
> <alex.bennee@linaro.org>; Pierrick Bouvier <pierrick.bouvier@linaro.org>; Paolo
> Bonzini <pbonzini@redhat.com>; Philippe Mathieu-Daudé <philmd@linaro.org>;
> Alexandre Iooss <erdnaxe@crans.org>; Richard Henderson
> <richard.henderson@linaro.org>; Mahmoud Mandour <ma.mandourr@gmail.com>
> Subject: [PATCH v3 1/7] plugins: fix mem callback array size
> 
> data was correctly copied, but size of array was not set
> (g_array_sized_new only reserves memory, but does not set size).
> 
> As a result, callbacks were not called for code path relying on
> plugin_register_vcpu_mem_cb().
> 
> Found when trying to trigger mem access callbacks for atomic
> instructions.
> 
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> ---
>  accel/tcg/plugin-gen.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/accel/tcg/plugin-gen.c b/accel/tcg/plugin-gen.c
> index b6bae32b997..ec89a085b43 100644
> --- a/accel/tcg/plugin-gen.c
> +++ b/accel/tcg/plugin-gen.c
> @@ -85,8 +85,7 @@ static void gen_enable_mem_helper(struct qemu_plugin_tb
> *ptb,
>      len = insn->mem_cbs->len;
>      arr = g_array_sized_new(false, false,
>                              sizeof(struct qemu_plugin_dyn_cb), len);
> -    memcpy(arr->data, insn->mem_cbs->data,
> -           len * sizeof(struct qemu_plugin_dyn_cb));
> +    g_array_append_vals(arr, insn->mem_cbs->data, len);
>      qemu_plugin_add_dyn_cb_arr(arr);
> 
>      tcg_gen_st_ptr(tcg_constant_ptr((intptr_t)arr), tcg_env,
> --
> 2.39.2
> 

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