arch-x86: Consider CPL in the decoder logic.

For instructions which simply require CPL0 (vs. requiring CPL is < IOPL,
or something else more complicated), this change either switches their
format so that they check that value before being returned, or adds a
comment marking them as privileged if they aren't yet implemented.

This change also makes the mov to/from CR and DR instructions more
particular, and returns an undefined instruction if the CR or DR index
is invalid.

Change-Id: I367d87a380a47428d458bda2ceecc1b983644704
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55891
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
3 files changed