4 ms·

AMD's implementation of DMTF DASH is called SimFire, and Intel's is called AMT. They both implement the same standard. I don't see where else it run if not on t

AMD's implementation of DMTF DASH is called SimFire, and Intel's is called AMT. They both implement the same standard. I don't see where else it run if not on the PSP if it works even when the machine is (supposedly) switched off? And even if it were not to run on the PSP, does that matter? It's still an opaque binary that runs below your OS. There's an older subthread on this at https://news.ycombinator.com/item?id=16081422 https://news.ycombinator.com/item?id=16081422 which also laments the lack of documentation on this.

_kbh_ 6y ago
its actually more interesting imo if it _doesn't_ run on the PSP; because that means that there is another processor that runs at a lower level than the x86 cores that can interact with the host and listens externally. After doing a bit of reading DMTF DASH appears to be implemented in the NIC from Broadcom or Realtek and uses the PCIE interface with the chipset from the NIC.
- lorenzhs 6y ago
  I would love for me to tell you that you were joking, but this sounds just crazy enough to be probably true. A cursory search confirms that the NIC seems to have a rather active role in DASH implementations: "To support out-of-band management, a client system typically requires a Network Controller that supports out-of-band management tasks, such as the Broadcom 5761." https://www.amd.com/system/files/documents/out-of-band-client-management-overview.pdf https://www.amd.com/system/files/documents/out-of-band-clien... (out-of-band management is the "it works while the machine is supposedly off" stuff) But it also needs to talk to the system BIOS / UEFI, so I guess something else needs to be running as well? "DASH functionality requires a communication channel between the hardware platform features, system BIOS, and the Broadcom NetXtreme™ Gigabit Ethernet Controller." (http://h10032.www1.hp.com/ctg/Manual/c01944865 http://h10032.www1.hp.com/ctg/Manual/c01944865). I mean, the PCIe interface is useless if the other end is actually off (and not just supposedly off).
  - _kbh_ 6y ago
    The second page of this document provides some details in diagrams. https://docs.broadcom.com/doc/1211168563383 https://docs.broadcom.com/doc/1211168563383 I presume it wakes up the chipset to do most of its work remotely.

_kbh_ 6y ago

its actually more interesting imo if it _doesn't_ run on the PSP; because that means that there is another processor that runs at a lower level than the x86 cores that can interact with the host and listens externally. After doing a bit of reading DMTF DASH appears to be implemented in the NIC from Broadcom or Realtek and uses the PCIE interface with the chipset from the NIC.

lorenzhs 6y ago
I would love for me to tell you that you were joking, but this sounds just crazy enough to be probably true. A cursory search confirms that the NIC seems to have a rather active role in DASH implementations: "To support out-of-band management, a client system typically requires a Network Controller that supports out-of-band management tasks, such as the Broadcom 5761." https://www.amd.com/system/files/documents/out-of-band-client-management-overview.pdf https://www.amd.com/system/files/documents/out-of-band-clien... (out-of-band management is the "it works while the machine is supposedly off" stuff) But it also needs to talk to the system BIOS / UEFI, so I guess something else needs to be running as well? "DASH functionality requires a communication channel between the hardware platform features, system BIOS, and the Broadcom NetXtreme™ Gigabit Ethernet Controller." (http://h10032.www1.hp.com/ctg/Manual/c01944865 http://h10032.www1.hp.com/ctg/Manual/c01944865). I mean, the PCIe interface is useless if the other end is actually off (and not just supposedly off).
- _kbh_ 6y ago
  The second page of this document provides some details in diagrams. https://docs.broadcom.com/doc/1211168563383 https://docs.broadcom.com/doc/1211168563383 I presume it wakes up the chipset to do most of its work remotely.