Re: [Qemu-devel] [PATCHv3 01/12] pseries: Split device tree construction from device tree load

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Quoting David Gibson (2016-10-24 00:04:32)
> spapr_finalize_fdt() both finishes building the device tree for the guest
> and loads it into guest memory.  For future cleanups, it's going to be
> more convenient to do these two things separately.  The loading portion is
> pretty trivial, so we move it inline into the caller, ppc_spapr_reset().
> 
> We also rename spapr_finalize_fdt(), because the current name is going to
> become inaccurate.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>

> ---
>  hw/ppc/spapr.c | 42 +++++++++++++++++++++++-------------------
>  1 file changed, 23 insertions(+), 19 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index ddb7438..0864411 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -900,10 +900,9 @@ int spapr_h_cas_compose_response(sPAPRMachineState *spapr,
>      return 0;
>  }
> 
> -static void spapr_finalize_fdt(sPAPRMachineState *spapr,
> -                               hwaddr fdt_addr,
> -                               hwaddr rtas_addr,
> -                               hwaddr rtas_size)
> +static void *spapr_build_fdt(sPAPRMachineState *spapr,
> +                             hwaddr rtas_addr,
> +                             hwaddr rtas_size)
>  {
>      MachineState *machine = MACHINE(qdev_get_machine());
>      MachineClass *mc = MACHINE_GET_CLASS(machine);
> @@ -999,19 +998,8 @@ static void spapr_finalize_fdt(sPAPRMachineState *spapr,
>          }
>      }
> 
> -    _FDT((fdt_pack(fdt)));
> -
> -    if (fdt_totalsize(fdt) > FDT_MAX_SIZE) {
> -        error_report("FDT too big ! 0x%x bytes (max is 0x%x)",
> -                     fdt_totalsize(fdt), FDT_MAX_SIZE);
> -        exit(1);
> -    }
> -
> -    qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt));
> -    cpu_physical_memory_write(fdt_addr, fdt, fdt_totalsize(fdt));
> -
>      g_free(bootlist);
> -    g_free(fdt);
> +    return fdt;
>  }
> 
>  static uint64_t translate_kernel_address(void *opaque, uint64_t addr)
> @@ -1147,6 +1135,8 @@ static void ppc_spapr_reset(void)
>      sPAPRMachineState *spapr = SPAPR_MACHINE(machine);
>      PowerPCCPU *first_ppc_cpu;
>      uint32_t rtas_limit;
> +    void *fdt;
> +    int rc;
> 
>      /* Check for unknown sysbus devices */
>      foreach_dynamic_sysbus_device(find_unknown_sysbus_device, NULL);
> @@ -1173,14 +1163,28 @@ static void ppc_spapr_reset(void)
>      spapr->rtas_addr = rtas_limit - RTAS_MAX_SIZE;
>      spapr->fdt_addr = spapr->rtas_addr - FDT_MAX_SIZE;
> 
> -    /* Load the fdt */
> -    spapr_finalize_fdt(spapr, spapr->fdt_addr, spapr->rtas_addr,
> -                       spapr->rtas_size);
> +    fdt = spapr_build_fdt(spapr, spapr->rtas_addr, spapr->rtas_size);
> 
>      /* Copy RTAS over */
>      cpu_physical_memory_write(spapr->rtas_addr, spapr->rtas_blob,
>                                spapr->rtas_size);
> 
> +    rc = fdt_pack(fdt);
> +
> +    /* Should only fail if we've built a corrupted tree */
> +    assert(rc == 0);
> +
> +    if (fdt_totalsize(fdt) > FDT_MAX_SIZE) {
> +        error_report("FDT too big ! 0x%x bytes (max is 0x%x)",
> +                     fdt_totalsize(fdt), FDT_MAX_SIZE);
> +        exit(1);
> +    }
> +
> +    /* Load the fdt */
> +    qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt));
> +    cpu_physical_memory_write(spapr->fdt_addr, fdt, fdt_totalsize(fdt));
> +    g_free(fdt);
> +
>      /* Set up the entry state */
>      first_ppc_cpu = POWERPC_CPU(first_cpu);
>      first_ppc_cpu->env.gpr[3] = spapr->fdt_addr;
> -- 
> 2.7.4
>