Re: [PATCH v4 05/10] samples/devsec: Introduce a PCI device-security bus + endpoint sample

[dan.j.williams]

Bjorn Helgaas wrote:
> On Thu, Jul 17, 2025 at 11:33:53AM -0700, Dan Williams wrote:
> > Establish just enough emulated PCI infrastructure to register a sample
> > TSM (platform security manager) driver and have it discover an IDE + TEE
> > (link encryption + device-interface security protocol (TDISP)) capable
> > device.
> > 
> > Use the existing a CONFIG_PCI_BRIDGE_EMUL to emulate an IDE capable root
> > port, and open code the emulation of an endpoint device via simulated
> > configuration cycle responses.
> 
> s/existing a/existing/

Fixed.

> 
> > The devsec_tsm driver responds to the PCI core TSM operations as if it
> > successfully exercised the given interface security protocol message.
> > 
> > The devsec_bus and devsec_tsm drivers can be loaded in either order to
> > reflect cases like SEV-TIO where the TSM is PCI-device firmware, and
> > cases like TDX Connect where the TSM is a software agent running on the
> > host CPU.
> > 
> > Follow-on patches add common code for TSM managed IDE establishment. For
> > now, just successfully complete setup and teardown of the DSM (device
> > security manager) context as a building block for management of TDI
> > (trusted device interface) instances.
> > 
> >  # modprobe devsec_bus
> >     devsec_bus devsec_bus: PCI host bridge to bus 10000:00
> >     pci_bus 10000:00: root bus resource [bus 00-01]
> >     pci_bus 10000:00: root bus resource [mem 0xf000000000-0xffffffffff 64bit]
> >     pci 10000:00:00.0: [8086:7075] type 01 class 0x060400 PCIe Root Port
> >     pci 10000:00:00.0: PCI bridge to [bus 00]
> >     pci 10000:00:00.0:   bridge window [io  0x0000-0x0fff]
> >     pci 10000:00:00.0:   bridge window [mem 0x00000000-0x000fffff]
> >     pci 10000:00:00.0:   bridge window [mem 0x00000000-0x000fffff 64bit pref]
> >     pci 10000:00:00.0: bridge configuration invalid ([bus 00-00]), reconfiguring
> >     pci 10000:01:00.0: [8086:ffff] type 00 class 0x000000 PCIe Endpoint
> >     pci 10000:01:00.0: BAR 0 [mem 0xf000000000-0xf0001fffff 64bit pref]
> >     pci_doe_abort: pci 10000:01:00.0: DOE: [100] Issuing Abort
> >     pci_doe_cache_protocols: pci 10000:01:00.0: DOE: [100] Found protocol 0 vid: 1 prot: 1
> >     pci 10000:01:00.0: disabling ASPM on pre-1.1 PCIe device.  You can enable it with 'pcie_aspm=force'
> >     pci 10000:00:00.0: PCI bridge to [bus 01]
> >     pci_bus 10000:01: busn_res: [bus 01] end is updated to 01
> 
> Most of these messages don't seem relevant to DSM/TDISP/etc.  It
> *would* be useful to have a hint about what specifically makes this an
> IDE + TEE device.  Capability visible via lspci?  Are devices at both
> ends required, e.g., a Root Port and an Endpoint?
> 
> Oooh, I see (finally).  This hierarchy is all totally fabricated, no
> actual hardware involved at all.  You did say that above; it just took
> a while to sink in.

Yeah, there are so many moving parts to this that I do not feel
comfortable leaving 100% of the testing to hardware. This is faster to
prototype than teaching QEMU to emulate all the pieces here.

> 
> >  # modprobe devsec_tsm
> >     devsec_tsm_pci_probe: pci 10000:01:00.0: devsec: tsm enabled
> >     __pci_tsm_init: pci 10000:01:00.0: TSM: Device security capabilities detected ( ide tee ), TSM attach
> 
> s/tsm/TSM/ in the message
> s/ide/IDE/
> s/tee/TEE/

Fixed.

> 
> Looks like spurious spaces inside parens?

Yeah just to avoid extra code to elide the separator, but easy enough to
fixup.

> > + * The expectation is the helpers referenceed are convenience "library"
> 
> s/referenceed/referenced/

Got it, checkpatch misses this one.