On Wed, Jul 11, 2018 at 4:29 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote: > From: Joerg Roedel <jroedel@xxxxxxx> > > Warn the user in case the performance can be significantly > improved by switching to a 64-bit kernel. ... > +#ifdef CONFIG_X86_32 > + if (boot_cpu_has(X86_FEATURE_PCID)) { I'm a bit confused. Wouldn't the setup_clear_cpu_cap() call in early_identify_cpu() prevent this from working? Boris, do we have a straightforward way to ask "does the CPU advertise this feature in CPUID regardless of whether we have it enabled right now"? --Andy