This only checks that it was available from the CPU.
To be complete an additional check should be made to show that it
was actually enabled from the firmware.
This will require a kernel modification though because MSR access
will be forbidden from userland while in kernel lockdown.
The HSI specification is currently incomplete and in active development.
Sample output for my Lenovo P50 Laptop:
Host Security ID: HSI:2+UA!
HSI-1
✔ UEFI dbx: OK
✔ TPM: v2.0
✔ SPI: Write disabled
✔ SPI: Lock enabled
✔ SPI: SMM required
✔ UEFI Secure Boot: Enabled
HSI-2
✔ TPM Reconstruction: Matched PCR0 reading
HSI-3
✘ Linux Kernel S3 Sleep: Deep sleep available
HSI-4
✘ Intel CET: Unavailable
Runtime Suffix -U
✔ Firmware Updates: Newest release is 8 months old
Runtime Suffix -A
✔ Firmware Attestation: OK
Runtime Suffix -!
✔ fwupd plugins: OK
✔ Linux Kernel: OK
✔ Linux Kernel: Locked down
✘ Linux Swap: Not encrypted
