When IA32_ARCH_CAPABILITIES (0x10a) can't be read from userspace (no msr
module, or kernel lockdown under Secure Boot), the FBSDP_NO/PSDP_NO/SBDR_SSDP_NO
bits were left at 0 ("explicitly not immune") instead of -1 ("unknown"). For a
recent CPU not in any kernel model list (e.g. Arrow Lake), this wrongly flipped
the MMIO Stale Data verdict into the "out of servicing period, Intel never
assessed this CPU" bucket.
Downfall:
- added `--kernel-config` support for all three Kconfig variants seen over all kernel versions up to now
- added `--kernel-map` support for `gds_select_mitigation` in `System.map`
- fixed the `--sysfs-only` mode
- added verbose information about remediation when `--explain` is used
- implemented `--paranoid mode`, requiring `GDS_MITIGATION_LOCKED` so that mitigation can't be disabled at runtime
- fixed offline mode (was wrongly looking at the system `dmesg`)
- better microcode status reporting (enabled, disabled, unsupported, unknown)
- fixed unknown (EOL) AVX-capable Intel family 6 CPUs now defaulting to affected
- fixed 2 missing known affected CPU models: INTEL_FAM6_SKYLAKE_L and INTEL_FAM6_SKYLAKE
- fixed case when we're running in a VM and the hypervisor doesn't let us read the MSR
Spectre V2:
- fix: affected_cpu: added Centaur family 7 (CentaurHauls) and Zhaoxin family 7 (Shanghai) as immune
- fix: added Centaur family 5 (CentaurHauls) and NSC family 5 (Geode by NSC) to is_cpu_specex_free()
- enh: offline mode: added detection logic by probing System.map and Kconfig
Stéphane Lesimple