Merge tag 'kvm-x86-misc-6.8' of https://github.com/kvm-x86/linux into HEAD

Merge tag 'kvm-x86-misc-6.8' of https://github.com/kvm-x86/linux into HEAD

KVM x86 misc changes for 6.8:

 - Turn off KVM_WERROR by default for all configs so that it's not
   inadvertantly enabled by non-KVM developers, which can be problematic for
   subsystems that require no regressions for W=1 builds.

 - Advertise all of the host-supported CPUID bits that enumerate IA32_SPEC_CTRL
   "features".

 - Don't force a masterclock update when a vCPU synchronizes to the current TSC
   generation, as updating the masterclock can cause kvmclock's time to "jump"
   unexpectedly, e.g. when userspace hotplugs a pre-created vCPU.

 - Use RIP-relative address to read kvm_rebooting in the VM-Enter fault paths,
   partly as a super minor optimization, but mostly to make KVM play nice with
   position independent executable builds.