[PATCH] powerpc: increase MIN RMA size for CAS negotiation

[Madhavan Srinivasan]

On 12/5/24 3:40 PM, Avnish Chouhan wrote:
> Change RMA size from 512 MB to 768 MB which will result 
> in more RMA at boot time for PowerPC. When PowerPC LPAR use/uses vTPM,
> Secure Boot or FADump, the 512 MB RMA memory is not sufficient for 
> booting. With this 512 MB RMA, GRUB2 run out of memory and unable to 
> load the necessary. Sometimes even usage of CDROM which requires more
> memory for installation along with the options mentioned above troubles
> the boot memory and result in boot failures. Increasing the RMA size 
> will resolves multiple out of memory issues observed in PowerPC. 

Can you add more on the failure details here list a stack trace or dump,
also is there a selftest to verify the fix in qemu or lpar?

> 
> 
> Signed-off-by: Avnish Chouhan <avnish at linux.ibm.com>
> ---
>  arch/powerpc/kernel/prom_init.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
> index fbb68fc28ed3..c42fd5a826c0 100644
> --- a/arch/powerpc/kernel/prom_init.c
> +++ b/arch/powerpc/kernel/prom_init.c
> @@ -1061,7 +1061,7 @@ static const struct ibm_arch_vec ibm_architecture_vec_template __initconst = {
>  		.virt_base = cpu_to_be32(0xffffffff),
>  		.virt_size = cpu_to_be32(0xffffffff),
>  		.load_base = cpu_to_be32(0xffffffff),
> -		.min_rma = cpu_to_be32(512),		/* 512MB min RMA */
> +		.min_rma = cpu_to_be32(768),		/* 768MB min RMA */
>  		.min_load = cpu_to_be32(0xffffffff),	/* full client load */
>  		.min_rma_percent = 0,	/* min RMA percentage of total RAM */
>  		.max_pft_size = 48,	/* max log_2(hash table size) */