Re: [PATCH 6/6] target/i386: Use env_archcpu() in simulate_[rdmsr/wrmsr]()

[Zhao Liu]

On Mon, Oct 09, 2023 at 01:02:39PM +0200, Philippe Mathieu-Daudé wrote:
> Date: Mon,  9 Oct 2023 13:02:39 +0200
> From: Philippe Mathieu-Daudé <philmd@linaro.org>
> Subject: [PATCH 6/6] target/i386: Use env_archcpu() in
>  simulate_[rdmsr/wrmsr]()
> X-Mailer: git-send-email 2.41.0
> 
> When CPUArchState* is available (here CPUX86State*), we can
> use the fast env_archcpu() macro to get ArchCPU* (here X86CPU*).
> The QOM cast X86_CPU() macro will be slower when building with
> --enable-qom-cast-debug.
> 
> Pass CPUX86State* as argument to simulate_rdmsr / simulate_wrmsr
> instead of a CPUState* to avoid an extra cast.
> 
> simulate_rdmsr/simulate_rdmsr(CPUX86State
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> RFC: Not even build-tested.
> ---
>  target/i386/hvf/x86_emu.h |  4 ++--
>  target/i386/hvf/hvf.c     |  4 ++--
>  target/i386/hvf/x86_emu.c | 21 ++++++++++-----------
>  3 files changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/target/i386/hvf/x86_emu.h b/target/i386/hvf/x86_emu.h
> index 640da90b30..4b846ba80e 100644
> --- a/target/i386/hvf/x86_emu.h
> +++ b/target/i386/hvf/x86_emu.h
> @@ -29,8 +29,8 @@ bool exec_instruction(CPUX86State *env, struct x86_decode 
> *ins);
>  void load_regs(struct CPUState *cpu);
>  void store_regs(struct CPUState *cpu);
>  
> -void simulate_rdmsr(struct CPUState *cpu);
> -void simulate_wrmsr(struct CPUState *cpu);
> +void simulate_rdmsr(CPUX86State *env);
> +void simulate_wrmsr(CPUX86State *env);
>  
>  target_ulong read_reg(CPUX86State *env, int reg, int size);
>  void write_reg(CPUX86State *env, int reg, target_ulong val, int size);
> diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c
> index cb2cd0b02f..20b9ca3ef5 100644
> --- a/target/i386/hvf/hvf.c
> +++ b/target/i386/hvf/hvf.c
> @@ -591,9 +591,9 @@ int hvf_vcpu_exec(CPUState *cpu)
>          {
>              load_regs(cpu);
>              if (exit_reason == EXIT_REASON_RDMSR) {
> -                simulate_rdmsr(cpu);
> +                simulate_rdmsr(env);
>              } else {
> -                simulate_wrmsr(cpu);
> +                simulate_wrmsr(env);
>              }
>              env->eip += ins_len;
>              store_regs(cpu);
> diff --git a/target/i386/hvf/x86_emu.c b/target/i386/hvf/x86_emu.c
> index af1f205ecf..b1f8a685d1 100644
> --- a/target/i386/hvf/x86_emu.c
> +++ b/target/i386/hvf/x86_emu.c
> @@ -663,11 +663,10 @@ static void exec_lods(CPUX86State *env, struct 
> x86_decode *decode)
>      env->eip += decode->len;
>  }
>  
> -void simulate_rdmsr(struct CPUState *cpu)
> +void simulate_rdmsr(CPUX86State *env)
>  {
> -    X86CPU *x86_cpu = X86_CPU(cpu);
> -    CPUX86State *env = &x86_cpu->env;
> -    CPUState *cs = env_cpu(env);
> +    X86CPU *x86_cpu = env_archcpu(env);
> +    CPUState *cpu = env_cpu(env);

I find these names are confusing since in other i386 file
(target/i386/cpu.c), the "X86CPU" is called "cpu", and the "CPUState" is
called "cs".

Regarding this naming, it may be worthy of cleanup to unify the naming
for i386. ;-)

>      uint32_t msr = ECX(env);
>      uint64_t val = 0;
>  
> @@ -746,8 +745,8 @@ void simulate_rdmsr(struct CPUState *cpu)
>          val = env->mtrr_deftype;
>          break;
>      case MSR_CORE_THREAD_COUNT:
> -        val = cs->nr_threads * cs->nr_cores; /* thread count, bits 15..0 */
> -        val |= ((uint32_t)cs->nr_cores << 16); /* core count, bits 31..16 */
> +        val = cpu->nr_threads * cpu->nr_cores;  /* thread count, bits 15..0 
> */
> +        val |= ((uint32_t)cpu->nr_cores << 16); /* core count, bits 31..16 */
>          break;
>      default:
>          /* fprintf(stderr, "%s: unknown msr 0x%x\n", __func__, msr); */
> @@ -761,14 +760,14 @@ void simulate_rdmsr(struct CPUState *cpu)
>  
>  static void exec_rdmsr(CPUX86State *env, struct x86_decode *decode)
>  {
> -    simulate_rdmsr(env_cpu(env));
> +    simulate_rdmsr(env);
>      env->eip += decode->len;
>  }
>  
> -void simulate_wrmsr(struct CPUState *cpu)
> +void simulate_wrmsr(CPUX86State *env)
>  {
> -    X86CPU *x86_cpu = X86_CPU(cpu);
> -    CPUX86State *env = &x86_cpu->env;
> +    X86CPU *x86_cpu = env_archcpu(env);
> +    CPUState *cpu = env_cpu(env);
>      uint32_t msr = ECX(env);
>      uint64_t data = ((uint64_t)EDX(env) << 32) | EAX(env);
>  
> @@ -856,7 +855,7 @@ void simulate_wrmsr(struct CPUState *cpu)
>  
>  static void exec_wrmsr(CPUX86State *env, struct x86_decode *decode)
>  {
> -    simulate_wrmsr(env_cpu(env));
> +    simulate_wrmsr(env);
>      env->eip += decode->len;
>  }

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>

-Zhao

>  
> -- 
> 2.41.0
> 
> 
>