On 28/08/2025 4:03 pm, Andrew Cooper wrote: > Of note, CR4.FRED is bit 32 and cannot enabled outside of 64bit mode. > > Most supported toolchains don't understand the FRED instructions yet. ERETU > and ERETS are easy to wrap (they encoded as REPZ/REPNE CLAC), while LKGS is > more complicated and deferred for now.
I've realised this is stale now. I'll replace with: Most supported toolchains don't understand the FRED instructions yet. ERETU and ERETS are easy to wrap (they encoded as REPZ/REPNE CLAC), while Xen turns out to have no need for LKGS. > > I have intentionally named the FRED MSRs differently to the spec. In the > spec, the stack pointer names alias the TSS fields of the same name, despite > very different semantics. > > Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com> > Acked-by: Jan Beulich <jbeul...@suse.com> > --- > CC: Jan Beulich <jbeul...@suse.com> > CC: Roger Pau Monné <roger....@citrix.com> > > v2: > * Drop CONFIG_HAS_AS_FRED I should have also noted "Add X86_FEATURE_XEN_FRED" here. ~Andrew
