On Thu, Jul 14, 2022 at 04:15:35PM -0700, Pawan Gupta wrote: > IBRS mitigation for spectre_v2 forces write to MSR_IA32_SPEC_CTRL at > every kernel entry/exit. On Enhanced IBRS parts setting > MSR_IA32_SPEC_CTRL[IBRS] only once at boot is sufficient. MSR writes at > every kernel entry/exit incur unnecessary performance loss. > > When Enhanced IBRS feature is present, print a warning about this > unnecessary performance loss. > > Signed-off-by: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx> > --- > v1->v2: Instead of changing the mitigation, print a warning about the > perf loss. > > v1: https://lore.kernel.org/lkml/0456b35fb9ef957d9a9138e0913fb1a3fd445dff.1657747493.git.pawan.kumar.gupta@xxxxxxxxxxxxxxx/ > > arch/x86/kernel/cpu/bugs.c | 3 +++ > 1 file changed, 3 insertions(+) <formletter> This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly. </formletter>
