Re: [PATCH 00/77] target/microblaze improvements

[Richard Henderson]

On 8/27/20 10:09 AM, Edgar E. Iglesias wrote:
> It seems to be getting out of sync when getting a slave-error and the core
> is not setup to take exceptions for slave errors. Looks like a pre-existing
> bug where we're restoring CPU state without taking the exception.
> The following fixes that particular case in my runs.
> 
> 
> I'm on a backported QEMU 5.1 so thing may look different in master.
> 
> diff --git a/target/microblaze/op_helper.c b/target/microblaze/op_helper.c
> index 831ff2cac1..0cae51c2df 100644
> --- a/target/microblaze/op_helper.c
> +++ b/target/microblaze/op_helper.c
> @@ -432,22 +432,19 @@ void mb_cpu_transaction_failed(CPUState *cs, hwaddr 
> physaddr, vaddr addr,
>      cpu = MICROBLAZE_CPU(cs);
>      env = &cpu->env;
>  
> -    cpu_restore_state(cs, retaddr, true);
> -    if (!(env->msr & MSR_EE)) {
> +    if (!cpu->cfg.iopb_bus_exception || !(env->msr & MSR_EE)) {
>          return;
>      }
>  
> +    cpu_restore_state(cs, retaddr, true);
> +
>      env->ear = addr;
>      if (access_type == MMU_INST_FETCH) {
> -        if ((env->pvr.regs[2] & PVR2_IOPB_BUS_EXC_MASK)) {
> -            env->esr = ESR_EC_INSN_BUS;
> -            helper_raise_exception(env, EXCP_HW_EXCP);
> -        }
> +        env->esr = ESR_EC_INSN_BUS;
> +        helper_raise_exception(env, EXCP_HW_EXCP);
>      } else {
> -        if ((env->pvr.regs[2] & PVR2_DOPB_BUS_EXC_MASK)) {
> -            env->esr = ESR_EC_DATA_BUS;
> -            helper_raise_exception(env, EXCP_HW_EXCP);
> -        }
> +        env->esr = ESR_EC_DATA_BUS;
> +        helper_raise_exception(env, EXCP_HW_EXCP);
>      }
>  }

Thanks for the pointer.  I've re-written this section to use
cpu_loop_exit_restore(), so that the restore is at the end.  The new patch will
appear in v2, just before iflags is added to the restore state.


r~