Re: [PATCH 3/7] ppc/pnv: Use skiboot addresses to load kernel and ramfs

[Joel Stanley]

On Tue, 26 Jan 2021 at 17:11, Cédric Le Goater <clg@kaod.org> wrote:
>
> The current settings are useful to load large kernels (with debug) but
> it moves the initrd image in a memory region not protected by
> skiboot. If skiboot is compiled with DEBUG=1, memory poisoning will
> corrupt the initrd.
>
> Cc: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>

Reviewed-by: Joel Stanley <joel@jms.id.au>

Note that the machine's default ram size will change with this patch:

 mc->default_ram_size = INITRD_LOAD_ADDR + INITRD_MAX_SIZE;

So we will go from 1.75GB to 768MB. Does anything break when the
machine has less than 1GB of ram?

> ---
>
>  If we want to increase the kernel size limit as commit b45b56baeecd
>  ("ppc/pnv: increase kernel size limit to 256MiB") intented to do, I
>  think we should add a machine option.
>
>  hw/ppc/pnv.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> index 14fc9758a973..e500c2e2437e 100644
> --- a/hw/ppc/pnv.c
> +++ b/hw/ppc/pnv.c
> @@ -65,9 +65,9 @@
>  #define FW_MAX_SIZE             (16 * MiB)
>
>  #define KERNEL_LOAD_ADDR        0x20000000
> -#define KERNEL_MAX_SIZE         (256 * MiB)
> -#define INITRD_LOAD_ADDR        0x60000000
> -#define INITRD_MAX_SIZE         (256 * MiB)
> +#define KERNEL_MAX_SIZE         (128 * MiB)
> +#define INITRD_LOAD_ADDR        0x28000000
> +#define INITRD_MAX_SIZE         (128 * MiB)
>
>  static const char *pnv_chip_core_typename(const PnvChip *o)
>  {
> --
> 2.26.2
>
>