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

["Cédric Le Goater" <clg@kaod.org>]

On 1/28/21 1:45 AM, Joel Stanley wrote:
> 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;

Ah yes. I missed that.

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

There is a warning if the machine has less than 1GB but we should
also change the default RAM size to 1G to be on the safe side.

Thanks,

C. 

> 
>> ---
>>
>>  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
>>
>>