RE: [PATCH v5 25/34] x86/fred: disallow the swapgs instruction when FRED is enabled

Li, Xin3
2023-03-20T18:08:13Z

> > The FRED architecture establishes the full supervisor/user through:
> > 1) FRED event delivery swaps the value of the GS base address and
> > that of the IA32_KERNEL_GS_BASE MSR.
> > 2) ERETU swaps the value of the GS base address and that of the
> > IA32_KERNEL_GS_BASE MSR.
> > Thus, the swapgs instruction is disallowed when FRED is enabled,
> > otherwise it cauess #UD.
> ^^^ --- new word :-)

My stupid fingers...