Re: [PATCH qemu v4] spapr: Kill SLOF

[Alexey Kardashevskiy]

On 08/01/2020 17:18, Alexey Kardashevskiy wrote:
> The Petitboot bootloader is way more advanced than SLOF is ever going to
> be as Petitboot comes with the full-featured Linux kernel with all
> the drivers, and initramdisk with quite user friendly interface.
> The problem with ditching SLOF is that an unmodified pseries kernel can
> either start via:
> 1. kexec, this requires presence of RTAS and skips
> ibm,client-architecture-support entirely;
> 2. normal boot, this heavily relies on the OF1275 client interface to
> fetch the device tree and do early setup (claim memory).
> 
> This adds a new bios-less mode to the pseries machine: "bios=on|off".
> When enabled, QEMU does not load SLOF and jumps to the kernel from
> "-kernel".


btw it occured to me that "of" (or "of-cli", or "of1275") is probably a
better name for the new option as there is still "bios" (those new 20
bytes with H_CLIENT) but this time QEMU implements the OF client interface.


>      fdt = spapr_build_fdt(spapr, true, FDT_MAX_SIZE);
>  
> -    rc = fdt_pack(fdt);
> -
> -    /* Should only fail if we've built a corrupted tree */
> -    assert(rc == 0);
> -
> -    /* Load the fdt */
> -    qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt));
> -    cpu_physical_memory_write(fdt_addr, fdt, fdt_totalsize(fdt));
>      g_free(spapr->fdt_blob);
>      spapr->fdt_size = fdt_totalsize(fdt);
>      spapr->fdt_initial_size = spapr->fdt_size;
>      spapr->fdt_blob = fdt;
>  
> -    /* Set up the entry state */
> -    spapr_cpu_set_entry_state(first_ppc_cpu, SPAPR_ENTRY_POINT, fdt_addr);
> -    first_ppc_cpu->env.gpr[5] = 0;
> +    if (spapr->bios_enabled) {
> +        /* Load the fdt */
> +        rc = fdt_pack(fdt);
> +        /* Should only fail if we've built a corrupted tree */
> +        assert(rc == 0);
> +
> +        spapr->fdt_size = fdt_totalsize(fdt);
> +        spapr->fdt_initial_size = spapr->fdt_size;
> +        qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt));
> +        cpu_physical_memory_write(fdt_addr, fdt, fdt_totalsize(fdt));



Inconsistency here, should have used here spapr->fdt_blob.




-- 
Alexey