phosphor-isolation

[James Feist]

On 9/19/19 8:47 PM, Andrew Jeffery wrote:
> 
> 
> On Fri, 20 Sep 2019, at 03:03, James Feist wrote:
>> I enabled phosphor-isolation on my system and noticed that kcs no longer
>> worked afterwards. Commenting out this section:
>>
>> https://github.com/openbmc/meta-phosphor/blob/a1cee09419cb1467c3d2b7bf996b40089f0d06f4/aspeed-layer/recipes-bsp/u-boot/files/0001-aspeed-Disable-unnecessary-features.patch#L230
>>
>> +	/* iLPC2AHB */
>> +	val = readl(AST_SCU_BASE + AST_SCU_HW_STRAP1);
>> +	val |= SCU_HW_STRAP_LPC_DEC_SUPER_IO;
>> +	writel(val, AST_SCU_BASE + AST_SCU_HW_STRAP1);
>>
>>
>> Seems to make KCS work again.
> 
> That is an unexpected result. Have you asked ASPEED about it? I've added
> Ryan to Cc. I must admit I didn't test the patch with systems that use KCS
> because OpenPOWER exclusively uses BT for IPMI (though we're starting
> to exploit the KCS interfaces for an LPC MCTP binding).
> 
> Having said that, the systems that we're testing our LPC MCTP binding on
> would have this patch applied, so presumably we're not seeing the same
> effect there. They're 2500-based systems, is that what you're testing with?

Yes I am.


> 
>> Do we need this part set? If so, should we
>> create a phosphor-isolation-kcs and phosphor-isolation-bt?
> 
> I hope not, given that leaving the SuperIO decoding enable allows the
> host to (slowly) scrape BMC memory (or if iLPC2AHB writes are allowed,
> open faster backdoors). We should root-cause the issue before exploring
> this path.
> 
> Andrew
>