Re: [PATCH v5 5/9] target/ppc: Simplify syscall exception handlers

[Harsh Prateek Bora <harshpb@linux.ibm.com>]

On 1/19/24 03:31, BALATON Zoltan wrote:
> After previous changes the hypercall handling in 7xx and 74xx
> exception handlers can be folded into one if statement to simpilfy
> this code. Also add "unlikely" to mark the less freqiently used branch
> for the compiler.
> 
> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>

Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>

> ---
>   target/ppc/excp_helper.c | 24 ++++++++----------------
>   1 file changed, 8 insertions(+), 16 deletions(-)
> 
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index 411d67376c..035a9fd968 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -762,26 +762,22 @@ static void powerpc_excp_7xx(PowerPCCPU *cpu, int excp)
>       case POWERPC_EXCP_SYSCALL:   /* System call exception                    */
>       {
>           int lev = env->error_code;
> -
> -        if (lev == 1 && cpu->vhyp) {
> -            dump_hcall(env);
> -        } else {
> -            dump_syscall(env);
> -        }
>           /*
>            * The Virtual Open Firmware (VOF) relies on the 'sc 1'
>            * instruction to communicate with QEMU. The pegasos2 machine
>            * uses VOF and the 7xx CPUs, so although the 7xx don't have
>            * HV mode, we need to keep hypercall support.
>            */
> -        if (lev == 1 && cpu->vhyp) {
> +        if (unlikely(lev == 1 && cpu->vhyp)) {
>               PPCVirtualHypervisorClass *vhc =
>                   PPC_VIRTUAL_HYPERVISOR_GET_CLASS(cpu->vhyp);
> +            dump_hcall(env);
>               vhc->hypercall(cpu->vhyp, cpu);
>               powerpc_reset_excp_state(cpu);
>               return;
> +        } else {
> +            dump_syscall(env);
>           }
> -
>           break;
>       }
>       case POWERPC_EXCP_FPU:       /* Floating-point unavailable exception     */
> @@ -907,26 +903,22 @@ static void powerpc_excp_74xx(PowerPCCPU *cpu, int excp)
>       case POWERPC_EXCP_SYSCALL:   /* System call exception                    */
>       {
>           int lev = env->error_code;
> -
> -        if (lev == 1 && cpu->vhyp) {
> -            dump_hcall(env);
> -        } else {
> -            dump_syscall(env);
> -        }
>           /*
>            * The Virtual Open Firmware (VOF) relies on the 'sc 1'
>            * instruction to communicate with QEMU. The pegasos2 machine
>            * uses VOF and the 74xx CPUs, so although the 74xx don't have
>            * HV mode, we need to keep hypercall support.
>            */
> -        if (lev == 1 && cpu->vhyp) {
> +        if (unlikely(lev == 1 && cpu->vhyp)) {
>               PPCVirtualHypervisorClass *vhc =
>                   PPC_VIRTUAL_HYPERVISOR_GET_CLASS(cpu->vhyp);
> +            dump_hcall(env);
>               vhc->hypercall(cpu->vhyp, cpu);
>               powerpc_reset_excp_state(cpu);
>               return;
> +        } else {
> +            dump_syscall(env);
>           }
> -
>           break;
>       }
>       case POWERPC_EXCP_FPU:       /* Floating-point unavailable exception     */