Re: [Qemu-ppc] [PATCH] pseries: Implements h_read hcall

[Alexander Graf]

On 07.02.2013, at 12:28, Erlon Cruz wrote:

> From: Erlon Cruz <address@hidden>
> 
> This h_call is useful for DLPAR in future amongst other things. Given an index
> it fetches the corresponding PTE stored in the htab.
> 
> Signed-off-by: Erlon Cruz <address@hidden>
> ---
> hw/spapr_hcall.c |   58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 58 insertions(+)
> 
> diff --git a/hw/spapr_hcall.c b/hw/spapr_hcall.c
> index 2889742..5ba07e5 100644
> --- a/hw/spapr_hcall.c
> +++ b/hw/spapr_hcall.c
> @@ -323,6 +323,63 @@ static target_ulong h_protect(PowerPCCPU *cpu, 
> sPAPREnvironment *spapr,
>     return H_SUCCESS;
> }
> 
> +static target_ulong h_read(PowerPCCPU *cpu, sPAPREnvironment *spapr,
> +                            target_ulong opcode, target_ulong *args)
> +{
> +    CPUPPCState *env = &cpu->env;
> +    target_ulong flags = args[0];
> +    target_ulong pte_index = args[1];
> +    uint8_t *hpte;
> +
> +    if ((pte_index * HASH_PTE_SIZE_64) & ~env->htab_mask) {
> +        return H_PARAMETER;
> +    }
> +
> +    if (!(flags & H_READ_4)) {
> +        target_ulong v, r;
> +        target_ulong *pteh = &args[0];
> +        target_ulong *ptel = &args[1];
> +
> +        hpte = env->external_htab + (pte_index * HASH_PTE_SIZE_64);

You are not guaranteed that there is an external htab.

In fact, looking at the external_htab users, we should probably introduce a few 
helper read functions for the htab that abstract the glorious 
external_htab/htab_base details away from you.


Alex