The 4.18 features for x86 aren‘t that boring either:
- x86: On all Intel systems, MSR_ARCH_CAPS is now visible in guests, and controllable from the VM’s config file. For CPUs from ~2019 onwards, this allows guest kernels to see details about hardware fixes for speculative mitigations.
- x86: Support for features new in AMD Genoa CPUs:
- x86: CPUID_USER_DIS (CPUID Faulting) used by Xen to control PV guest’s view of CPUID data.
- x86: Support for features new in Intel Sapphire Rapids CPUs:
- PKS (Protection Key Supervisor) available to HVM/PVH guests
- VM-Notify used by Xen to mitigate certain micro-architectural pipeline livelocks, instead of crashing the entire server
- Bus-lock detection, used by Xen to mitigate (by rate-limiting) the systemwide impact of a guest misusing atomic instructions
- x86: Support for features new in Intel Granite Rapids CPUs: AVX512-FP16
- x86: Add Intel Hardware P-States (HWP) cpufreq driver
- x86: Support for enforcing system-wide operation in Data Operand Independent Timing Mode