[2/4] hw/ppc/spapr: Implement h_set_dabr

According to LoPAPR, h_set_dabr should simply set DABRX to 3
(if the register is available), and load the parameter into DABR.
If DABRX is not available, the hypervisor has to check the
"Breakpoint Translation" bit of the DABR register first.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 hw/ppc/spapr_hcall.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

On Wed, Feb 10, 2016 at 07:09:10PM +0100, Thomas Huth wrote:
> According to LoPAPR, h_set_dabr should simply set DABRX to 3
> (if the register is available), and load the parameter into DABR.
> If DABRX is not available, the hypervisor has to check the
> "Breakpoint Translation" bit of the DABR register first.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  hw/ppc/spapr_hcall.c | 26 +++++++++++++++++++++-----
>  1 file changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 58103ef..6b9d512 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -38,6 +38,12 @@ static void set_spr(CPUState *cs, int spr, target_ulong value,
>      run_on_cpu(cs, do_spr_sync, &s);
>  }
>  
> +static bool has_spr(PowerPCCPU *cpu, int spr)
> +{
> +    /* We can test whether the SPR is defined by checking for a valid name */
> +    return cpu->env.spr_cb[spr].name != NULL;
> +}
> +
>  static inline bool valid_pte_index(CPUPPCState *env, target_ulong pte_index)
>  {
>      /*
> @@ -344,8 +350,20 @@ static target_ulong h_set_sprg0(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>  static target_ulong h_set_dabr(PowerPCCPU *cpu, sPAPRMachineState *spapr,
>                                 target_ulong opcode, target_ulong *args)
>  {
> -    /* FIXME: actually implement this */
> -    return H_HARDWARE;
> +    CPUState *cs = CPU(cpu);
> +
> +    if (!has_spr(cpu, SPR_DABR)) {
> +        return H_HARDWARE;          /* DABR register not available */
> +    }
> +
> +    if (has_spr(cpu, SPR_DABRX)) {
> +        set_spr(cs, SPR_DABRX, 0x3, -1L);

As in the previous patch, we shouldn't need the fancy run_on_cpu stuff
that set_spr() uses, since this is just a cpu local register update.

> +    } else if (!(args[0] & 0x4)) {  /* Breakpoint Translation set? */
> +        return H_RESERVED_DABR;
> +    }
> +
> +    set_spr(cs, SPR_DABR, args[0], -1L);
> +    return H_SUCCESS;
>  }
>  
>  #define FLAGS_REGISTER_VPA         0x0000200000000000ULL
> @@ -999,15 +1017,13 @@ static void hypercall_register_types(void)
>      /* hcall-bulk */
>      spapr_register_hypercall(H_BULK_REMOVE, h_bulk_remove);
>  
> -    /* hcall-dabr */
> -    spapr_register_hypercall(H_SET_DABR, h_set_dabr);
> -
>      /* hcall-splpar */
>      spapr_register_hypercall(H_REGISTER_VPA, h_register_vpa);
>      spapr_register_hypercall(H_CEDE, h_cede);
>  
>      /* processor register resource access h-calls */
>      spapr_register_hypercall(H_SET_SPRG0, h_set_sprg0);
> +    spapr_register_hypercall(H_SET_DABR, h_set_dabr);
>      spapr_register_hypercall(H_SET_MODE, h_set_mode);
>  
>      /* "debugger" hcalls (also used by SLOF). Note: We do -not- differenciate