On 12.01.2023 14:58, Andrew Cooper wrote: > On 12/01/2023 12:58 pm, Jan Beulich wrote: >> Do you have any indications towards a CS prefix being the least risky >> one to use here (or in general)? > > Yes. > > Remember it's the prefix recommended for, and used by, > -mbranches-within-32B-boundaries to work around the Skylake jmp errata. > > And based on this justification, its also the prefix we use for padding > on various jmp/call's for retpoline inlining purposes.
While I'm okay with the reply, I'd like to point out that in those cases address or operand size prefix simply could not have been used, for the insns in question having explicit operands which would be affected. Which is unlike the case here. Jan
