Re: [PATCH v1 1/3] x86/cpu/AMD: Make LFENCE a serializing instruction

[Brian Gerst]

On Fri, Jan 5, 2018 at 11:07 AM, Tom Lendacky <thomas.lendacky@xxxxxxx> wrote:
> To aid in speculation control, make LFENCE a serializing instruction.
> This is done by setting bit 1 of MSR 0xc0011029 (DE_CFG).  Some families
> that support LFENCE do not have this MSR.  For these families, the LFENCE
> instruction is already serializing.

Does this require a microcode update?

--
Brian Gerst