Re: [PATCH 2/6] contrib/plugins/cache: fix warning when compiling on 32bits host

[Thomas Huth]

On 15/08/2024 01.36, Pierrick Bouvier wrote:
> Found on debian stable (i386).
>
> ../contrib/plugins/cache.c: In function 'vcpu_tb_trans':
> ../contrib/plugins/cache.c:477:30: error: cast from pointer to integer of 
> different size [-Werror=pointer-to-int-cast]
>    477 |             effective_addr = (uint64_t) qemu_plugin_insn_haddr(insn);
>        |
>
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> ---
>   contrib/plugins/cache.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/contrib/plugins/cache.c b/contrib/plugins/cache.c
> index 512ef6776b7..82ed734d6d4 100644
> --- a/contrib/plugins/cache.c
> +++ b/contrib/plugins/cache.c
> @@ -471,12 +471,12 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct 
> qemu_plugin_tb *tb)
>       n_insns = qemu_plugin_tb_n_insns(tb);
>       for (i = 0; i < n_insns; i++) {
>           struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
> -        uint64_t effective_addr;
> +        uintptr_t effective_addr;
>   
>           if (sys) {
> -            effective_addr = (uint64_t) qemu_plugin_insn_haddr(insn);
> +            effective_addr = (uintptr_t) qemu_plugin_insn_haddr(insn);
>           } else {
> -            effective_addr = (uint64_t) qemu_plugin_insn_vaddr(insn);
> +            effective_addr = (uintptr_t) qemu_plugin_insn_vaddr(insn);
>           }

Is this the right fix? I assume effective_addr stores an address of the 
guest, so if the guest is 64-bit and the host is 32-bit, you now lose the 
upper bits of the address...?

The casting for qemu_plugin_insn_vaddr is not required at all since it 
already returns an uint64_t, so you can remoe that one. For the haddr part, 
maybe do a double-cast:

  effective_addr = (uint64_t)(uintptr_t)qemu_plugin_insn_haddr(insn)

?

 Thomas