Read CPU memory from BMC.

[Joseph Reynolds]

On 8/26/22 11:42 AM, AKASH G J wrote:
> Hello Team, Is it possible to read CPU memory space from the BMC? If 
> PCIe connection is available from BMC to the chipset, can we do DMA 
> from BMC ? Thanks and Regards, Akash ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ ‍ 
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> Hello Team,
>
> Is it possible to read CPU memory space from the BMC?
> If PCIe connection is available from BMC to the chipset, can we do DMA 
> from BMC ?

Akash,

I hope not.  I assume you are asking about how to read the host's memory 
from the BMC.  I believe the ability for the BMC to read host memory is 
not a non-goal.

I understand a fundamental BMC design point is to have a security 
boundary between the BMC and host elements (like the host processor and 
host memory), so that:
- The BMC has strictly limited access to the host elements is need to 
interact with, and
- The host has strictly limited access to BMC resources it needs to 
interact with.

This separation is a goal for POWER Systems, and I think also for Intel, 
AMD, etc.  But I don't see this in any OpenBMC documentation.

-Joseph

>
>
> Thanks and Regards,
>
> Akash