Re: [PATCH v2 12/12] accel/tcg: Avoid unnecessary call overhead from qemu_plugin_vcpu_mem_cb

[Alwalid Salama <quic_asalama@xxxxxxxxxxx>]

Reviewed-by: Alwalid Salama <quic_asalama@xxxxxxxxxxxx>

On 6/20/2024 5:22 PM, Alex Bennée wrote:
> From: Max Chou <max.chou@xxxxxxxxxx>
>
> If there are not any QEMU plugin memory callback functions, checking
> before calling the qemu_plugin_vcpu_mem_cb function can reduce the
> function call overhead.
>
> Signed-off-by: Max Chou <max.chou@xxxxxxxxxx>
> Reviewed-by: Richard Henderson <richard.henderson@xxxxxxxxxx>
> Reviewed-by: Frank Chang <frank.chang@xxxxxxxxxx>
> Message-Id: <20240613175122.1299212-2-max.chou@xxxxxxxxxx>
> ---
>   accel/tcg/ldst_common.c.inc | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/accel/tcg/ldst_common.c.inc b/accel/tcg/ldst_common.c.inc
> index c82048e377..87ceb95487 100644
> --- a/accel/tcg/ldst_common.c.inc
> +++ b/accel/tcg/ldst_common.c.inc
> @@ -125,7 +125,9 @@ void helper_st_i128(CPUArchState *env, uint64_t addr, Int128 val, MemOpIdx oi)
>   
>   static void plugin_load_cb(CPUArchState *env, abi_ptr addr, MemOpIdx oi)
>   {
> -    qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
> +    if (cpu_plugin_mem_cbs_enabled(env_cpu(env))) {
> +        qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_R);
> +    }
>   }
>   
>   uint8_t cpu_ldb_mmu(CPUArchState *env, abi_ptr addr, MemOpIdx oi, uintptr_t ra)
> @@ -188,7 +190,9 @@ Int128 cpu_ld16_mmu(CPUArchState *env, abi_ptr addr,
>   
>   static void plugin_store_cb(CPUArchState *env, abi_ptr addr, MemOpIdx oi)
>   {
> -    qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
> +    if (cpu_plugin_mem_cbs_enabled(env_cpu(env))) {
> +        qemu_plugin_vcpu_mem_cb(env_cpu(env), addr, oi, QEMU_PLUGIN_MEM_W);
> +    }
>   }
>   
>   void cpu_stb_mmu(CPUArchState *env, abi_ptr addr, uint8_t val,